+publisher:"University of Michigan" +contributor:("Kim, Jinsang")

University of Michigan

1. Doleyres, Yasmine. Temporal and Spatial Nanobiomaterials for Tissue Engineering and Drug Delivery.

Degree: PhD, Macromolecular Science & Engineering, 2020, University of Michigan

URL: http://hdl.handle.net/2027.42/163136

► The intersection of materials science, biology, and nanotechnology has allowed for the development of advanced nanobiomaterials for tissue engineering and drug delivery. With more knowledge… (more)

▼ The intersection of materials science, biology, and nanotechnology has allowed for the development of advanced nanobiomaterials for tissue engineering and drug delivery. With more knowledge of how physical and chemical properties of a biomaterial influence cell function and response, it is important to impart different characteristics to materials with which cells will interact. Characteristics to consider for tissue engineering and/or drug delivery applications include: biocompatibility, mechanical properties, surface area, and ligand presentation. As foreign materials that are placed into the body and are not necessary permanently, these materials should also be biodegradable. Previous biomaterials have fallen short in many ways (i.e. lack of degradability, poor modulus matching, lack of porosity), as it is difficult to design a material with all necessary attributes. The more biomimetic and tailorable a material is, the better suited it is for these applications. New chemistries and approaches must be considered to incorporate all necessary characteristics. This work introduces two new materials that are characterized and evaluated for biomaterials applications and successfully overcome the temporal and spatial shortcomings of previous research. 2-methylene-1,3,6-trioxocane (MTC) is a hydrophobic monomer that is crosslinked with poly(ethylene glycol) diacrylate, a hydrophilic crosslinker, at varying crosslinker concentrations and molecular weights. In this work, with respect to tissue engineering, the materials’ morphological changes, swelling, degradation, and elastic modulus properties are all assessed. Tunability is found in these properties as the crosslinker is adjusted and a hydrophobic-hydrophilic balance dictates many behavioral properties, including an atypical increase in swelling as crosslinker concentration is increased. The biocompatibility is assessed with MTC formulations with 575 Da and 2 kDa crosslinker at 1.0% crosslinker concentrations exhibiting moderate swelling (< 100%) and modulus of ~100 kPa showing good biocompatibility and utility for soft tissue engineering applications. As a drug delivery system (DDS), crosslinked MTC samples were evaluated in terms of tunability and kinetics of drug release behavior. Drug release was tested for three different types of drugs: small molecule hydrophobic, small molecule hydrophilic, and a protein. From the 10-week studies, MTC hydrogels importantly demonstrated suitability for controlled release of the small molecule hydrophobic drug, with constant zero order kinetics displayed across crosslinker variations at physiological pH; the model protein, exhibited first order behavior and increasing drug release as crosslinker concentration increases. Rapid, 1 minute subcutaneous in situ gelling was also demonstrated in a mouse, making MTC advantageous as an injectable DDS. Finally, polymeric nanoparticle functionalization is explored to improve drug targeting/internalization to treat HER2+ breast cancer. This strategy is tested by (1) comparing nanoparticles… Advisors/Committee Members: Kim, Jinsang (committee member), Kuroda, Kenichi (committee member), Lahann, Joerg (committee member), Wang, Suhe (committee member).

Subjects/Keywords: biomaterials; Biomedical Engineering; Engineering (General); Materials Science and Engineering; Chemistry; Science (General); Engineering; Science

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Doleyres, Y. (2020). Temporal and Spatial Nanobiomaterials for Tissue Engineering and Drug Delivery. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/163136

Chicago Manual of Style (16^th Edition):

Doleyres, Yasmine. “Temporal and Spatial Nanobiomaterials for Tissue Engineering and Drug Delivery.” 2020. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/163136.

MLA Handbook (7^th Edition):

Doleyres, Yasmine. “Temporal and Spatial Nanobiomaterials for Tissue Engineering and Drug Delivery.” 2020. Web. 12 Apr 2021.

Vancouver:

Doleyres Y. Temporal and Spatial Nanobiomaterials for Tissue Engineering and Drug Delivery. [Internet] [Doctoral dissertation]. University of Michigan; 2020. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/163136.

Council of Science Editors:

Doleyres Y. Temporal and Spatial Nanobiomaterials for Tissue Engineering and Drug Delivery. [Doctoral Dissertation]. University of Michigan; 2020. Available from: http://hdl.handle.net/2027.42/163136

University of Michigan

2. Dong, Ban. Microstructure and Carrier Transport Processes in Semiconducting Polymers.

Degree: PhD, Materials Science and Engineering, 2017, University of Michigan

URL: http://hdl.handle.net/2027.42/138715

► The molecular design and synthesis of semiconducting conjugated polymers was a major achievement in the field of chemistry, enabling the now viable organic electronics industry.… (more)

▼ The molecular design and synthesis of semiconducting conjugated polymers was a major achievement in the field of chemistry, enabling the now viable organic electronics industry. Unlike their crystalline inorganic counterparts, the weak van der Waals bonding forces between conjugated polymer chains give rise to significant structural and energetic disorder. This reduces charge carrier mobility and adversely impacts device performances. Efforts to understand carrier transport in conjugated polymer systems have been challenged due to the complexity of the structure and a lack of proper understanding of the manner in which the polymer morphology affects electrical properties. This thesis focuses on developing several experimental strategies to turn polymer morphologies and studying the impact of polymer microstructure on carrier transport. The experimental approaches for morphology manipulation in this thesis include (i) fabricating film with different thickness (ii) using the environmentally benign method supercritical carbon dioxide processing and (iii) using a novel vacuum deposition technique to deposit thin polymer films. By studying thickness dependence of morphology and carrier transport in a low bandgap polymer, we show that the out-of-plane carrier mobilities in conjugated polymer films monotonically increase with thickness in the range of 100 nm to 1 μm due to substrate-induced morphological changes as a function of film thickness. Our findings demonstrate that carrier mobility in conjugated polymers is not intrinsic properties of the materials but rather dictated by local morphology; it could vary nearly by an order of magnitude depend on the proximity to the substrate. For the second route, we show how the polymer structure near polymer/substrate interface in organic thin film transistor can be selectively manipulated using supercritical carbon dioxide processing. Subsequently, we observe a significant enhancement in the in-plane carrier mobility that is accompanied by rather a subtle change in polymer morphology. This demonstrates that supercritical carbondioxide processing is an effective way to control polymer structure near the buried interface. Lastly, we introduce a novel vacuum deposition technique Matrix-Assisted Pulse Laser Evaporation (MAPLE) to fabricate conjugated polymer films. Although the structure of MAPLE-deposited samples is highly disordered, transistor devices made from MAPLE-deposited films exhibit superior in-plane transport characteristics. Motivated by this finding, we then employ an advanced X-ray characterization method called complete pole figure construction and characterize the polymer structure at different stage of deposition in order to reveal the structure of MAPLE-deposited films at the buried interface. To our surprise we discover a large population of highly-oriented crystals at the buried interface having structure strongly depending on the substrate chemistry. We also show that this polymer layer dictates transport in thin film transistor, showing the importance of… Advisors/Committee Members: Green, Peter F (committee member), Zhong, Zhaohui (committee member), Kim, Jinsang (committee member), Tuteja, Anish (committee member).

Subjects/Keywords: Semiconducting polymer; structure-transport relationship; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dong, B. (2017). Microstructure and Carrier Transport Processes in Semiconducting Polymers. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/138715

Chicago Manual of Style (16^th Edition):

Dong, Ban. “Microstructure and Carrier Transport Processes in Semiconducting Polymers.” 2017. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/138715.

MLA Handbook (7^th Edition):

Dong, Ban. “Microstructure and Carrier Transport Processes in Semiconducting Polymers.” 2017. Web. 12 Apr 2021.

Vancouver:

Dong B. Microstructure and Carrier Transport Processes in Semiconducting Polymers. [Internet] [Doctoral dissertation]. University of Michigan; 2017. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/138715.

Council of Science Editors:

Dong B. Microstructure and Carrier Transport Processes in Semiconducting Polymers. [Doctoral Dissertation]. University of Michigan; 2017. Available from: http://hdl.handle.net/2027.42/138715

University of Michigan

3. Lee, Kyu-Tae. Ultra-Thin Highly Absorbing Medium-Based Optical Nanocavity for Photonic and Optoelectronic Devices.

Degree: PhD, Electrical Engineering, 2015, University of Michigan

URL: http://hdl.handle.net/2027.42/113617

► Optical cavities, which generally consist of an optically transparent medium with wavelength-scale thickness, have been widely used in various areas ranging from lasers and modulators… (more)

▼ Optical cavities, which generally consist of an optically transparent medium with wavelength-scale thickness, have been widely used in various areas ranging from lasers and modulators to sensors and filters. A trivial optical absorption in the cavity allows incident light to constructively interfere with reflected light many times without serious loss, thus being able to create a resonance at a certain wavelength. However, a traditional optical cavity has faced challenges in achieving an angle-insensitive property, thereby dramatically limiting their applications in a wide variety of fields. In this dissertation, we present several demonstrations, all based on optical nanocavities featuring strong resonance behaviors in highly absorbing media with the ultra-thin cavity thickness (< 30 nm) as compared to the wavelength of incident light, which is distinctly different from the conventional optical cavity systems. We firstly demonstrate angle invariant (up to 70°) transmissive and reflective structural color filters with high-color-purity exploiting a concept described above. We also present a new photovoltaic (PV) scheme incorporating novel optical design (ultra-thin cavity) and electrical design (dopant-free amorphous silicon) to create colored semitransparent PV cells, which could be harmoniously integrated with interiors and exteriors of the buildings, such as facades, windows, ceilings, and walls. This enables large surfaces of architectures to be efficiently utilized to generate the electric power. ~3 (2)% of power conversion efficiency with desired reflective (transmissive) colors that are insensitive to the angle of incidence and the polarization state of incident light is achieved. To improve the power conversion efficiency of the colored PV cells, we propose and experimentally demonstrate a spectrum splitting method and microcavity-integrated PV scheme, both of which show ~4% of power conversion efficiency. Lastly, we describe how our strategy could be applied to other applications, such as perovskite PV cells, broadband visible absorbers, and low reflective wire grid polarizers. The presented approach could open door to numerous applications, such as energy-efficient ultra-thin colored display technologies and decorative building-integrated PV. Advisors/Committee Members: Guo, L. Jay (committee member), Kim, Jinsang (committee member), Phillips, Jamie Dean (committee member), Zhong, Zhaohui (committee member).

Subjects/Keywords: Optics/Photonics; Electrical Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lee, K. (2015). Ultra-Thin Highly Absorbing Medium-Based Optical Nanocavity for Photonic and Optoelectronic Devices. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/113617

Chicago Manual of Style (16^th Edition):

Lee, Kyu-Tae. “Ultra-Thin Highly Absorbing Medium-Based Optical Nanocavity for Photonic and Optoelectronic Devices.” 2015. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/113617.

MLA Handbook (7^th Edition):

Lee, Kyu-Tae. “Ultra-Thin Highly Absorbing Medium-Based Optical Nanocavity for Photonic and Optoelectronic Devices.” 2015. Web. 12 Apr 2021.

Vancouver:

Lee K. Ultra-Thin Highly Absorbing Medium-Based Optical Nanocavity for Photonic and Optoelectronic Devices. [Internet] [Doctoral dissertation]. University of Michigan; 2015. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/113617.

Council of Science Editors:

Lee K. Ultra-Thin Highly Absorbing Medium-Based Optical Nanocavity for Photonic and Optoelectronic Devices. [Doctoral Dissertation]. University of Michigan; 2015. Available from: http://hdl.handle.net/2027.42/113617

University of Michigan

4. Chung, Kyeongwoon. Design of Organic Materials with Unique Supramolecular Assembly for Optical, Electronic, and Biomedical Applications.

Degree: PhD, Macromolecular Science and Engineering, 2016, University of Michigan

URL: http://hdl.handle.net/2027.42/133216

► Rational material design is inevitable to fully realize the properties of organic conjugated materials in applications, by regulating their intermolecular packing as well as intramolecular… (more)

▼ Rational material design is inevitable to fully realize the properties of organic conjugated materials in applications, by regulating their intermolecular packing as well as intramolecular properties. In this dissertation, molecular design strategies to control interactions and assemblies of organic conjugated materials are systematically investigated, which enables unique optoelectronic properties for various optoelectronic applications. In Chapter 2, a molecular design to control intermolecular interactions renders a unique thermally stable supercooled liquid and its shear-triggered lighting-up crystallization with 25-times fluorescence enhancement. The origin of the unique property is systematically scrutinized. Furthermore, possible biosensor application is proposed by demonstrating highly sensitive crystallization of the supercooled liquid by living cell attachment. Insightful design consideration for both intrachain and interchain properties is also critically important for conjugated polymers (CPs). In Chapter 3, molecular design of CPs’ main and side chains is logically investigated to regulate optical properties. Tailored CPs exhibit identical color in solution manifesting the same intramolecular optical properties by conjugated backbone design. Contrastingly, they show distinct color gradation in the solid state due to the coined intermolecular packing propensity difference through side chain design. Latent optical information encoding using CPs as security inks is demonstrated, which reveals and conceals hidden information upon CP aggregation/deaggregation. Furthermore, expansion of the design principles for efficient CP alignment is investigated (Chapter 4). Realization of CP alignment largely affects optoelectronic applications of CPs since it is inevitable to fully utilize CPs’ anisotropic properties in devices. Previously identified molecular design rules to realize directed CP alignment are evaluated, and more detailed design factors are additionally revealed. The properties of organic conjugated materials are also influenced by environmental factors, including characteristics of a substrate and solvent molecules. In Chapter 5, a novel optical sensor is devised based on controlled subtle interaction differences between substrates, fluorescent sensory molecules, and analyte solvents. The highly selective sensor array can clearly distinguish physicochemically similar liquids; ethanol, methanol, ethylene glycol, and water. The thoroughly discussed molecular design principles in this dissertation depict an insightful picture on how unique optoelectronic properties of conjugated organic molecules and polymers can be designed and fully utilized in various applications. Advisors/Committee Members: Kim, Jinsang (committee member), McNeil, Anne Jennifer (committee member), Guo, L Jay (committee member), Kioupakis, Emmanouil (committee member).

Subjects/Keywords: Materials Design; Organic Conjugated Materials; Intermolecular Interaction; Supramolecular Assembly; Optoelectronic Application; Biomedical Application; Materials Science and Engineering; Chemistry; Engineering; Science

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Chung, K. (2016). Design of Organic Materials with Unique Supramolecular Assembly for Optical, Electronic, and Biomedical Applications. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/133216

Chicago Manual of Style (16^th Edition):

Chung, Kyeongwoon. “Design of Organic Materials with Unique Supramolecular Assembly for Optical, Electronic, and Biomedical Applications.” 2016. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/133216.

MLA Handbook (7^th Edition):

Chung, Kyeongwoon. “Design of Organic Materials with Unique Supramolecular Assembly for Optical, Electronic, and Biomedical Applications.” 2016. Web. 12 Apr 2021.

Vancouver:

Chung K. Design of Organic Materials with Unique Supramolecular Assembly for Optical, Electronic, and Biomedical Applications. [Internet] [Doctoral dissertation]. University of Michigan; 2016. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/133216.

Council of Science Editors:

Chung K. Design of Organic Materials with Unique Supramolecular Assembly for Optical, Electronic, and Biomedical Applications. [Doctoral Dissertation]. University of Michigan; 2016. Available from: http://hdl.handle.net/2027.42/133216

University of Michigan

5. Kim, Gun Ho. Thermoelectric Transport in Organic Materials.

Degree: PhD, Mechanical Engineering, 2013, University of Michigan

URL: http://hdl.handle.net/2027.42/102350

► Organic materials are well-suited to certain applications due to their low cost, low weight, and mechanical flexibility, but are less desirable for other applications due… (more)

▼ Organic materials are well-suited to certain applications due to their low cost, low weight, and mechanical flexibility, but are less desirable for other applications due to poor conduction of electricity and heat. The contributions of my work focus on strategies to mitigate these limitations in current and emerging organic materials, developing techniques to improve charge carrier mobility in doped organic semiconductors (OSCs) and improve thermal conductivity in common commercial plastic materials. Understanding of charge carrier transport is a prerequisite to developing a good electrical conductor. In OSCs, charge carriers are historically assumed to be strongly localized, which bears heavily on their assumed mechanism of transport; however, the degree of localization in emerging high-conductivity OSCs has been the subject of intense study. My work develops a model that can be used with thermoelectric measurements to quantitatively determine the degree of carrier localization in an OSC, and applies this technique to high-conductivity polymers and iodine-doped pentacene films. The model also suggests a strategy to improve energy conversion efficiency in OSC-based thermoelectric materials by reducing dopant volume. This strategy was confirmed experimentally to vary all three thermoelectric parameters (Seebeck coefficient, electrical conductivity, and thermal conductivity) in a manner that increases thermoelectric efficiency, in sharp contrast to their trade-offs in common inorganic semiconductor based thermoelectric materials. This method led to 70% increase in the thermoelectric efficiency from the previous record for an OSC. Finally, I propose and study methods to increase inter-chain bonding in polymer mixtures as an efficient engineering route to improve their thermal conductivity. By controlling the mole fractions of components to favor (strong) hydrogen bonds over weaker van der Waals bonds, the thermal conductivities of mixtures of common commercial polymers are increased by an order of magnitude, reaching 1.72 W/mK, the highest value yet reported among non-crystalline polymer materials without the incorporation of fillers. Advisors/Committee Members: Pipe, Kevin Patrick (committee member), Shtein, Max (committee member), Sangi Reddy, Pramod (committee member), Kurabayashi, Katsuo (committee member), Kim, Jinsang (committee member).

Subjects/Keywords: Organic Materials; Thermoelectric Conversion Efficiency; Charge Carrier Transport; Thermal Transport; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kim, G. H. (2013). Thermoelectric Transport in Organic Materials. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/102350

Chicago Manual of Style (16^th Edition):

Kim, Gun Ho. “Thermoelectric Transport in Organic Materials.” 2013. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/102350.

MLA Handbook (7^th Edition):

Kim, Gun Ho. “Thermoelectric Transport in Organic Materials.” 2013. Web. 12 Apr 2021.

Vancouver:

Kim GH. Thermoelectric Transport in Organic Materials. [Internet] [Doctoral dissertation]. University of Michigan; 2013. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/102350.

Council of Science Editors:

Kim GH. Thermoelectric Transport in Organic Materials. [Doctoral Dissertation]. University of Michigan; 2013. Available from: http://hdl.handle.net/2027.42/102350

University of Michigan

6. Leone, Amanda. Using Mechanistic Insight to Develop Living Polymerizations for Conjugated Homopolymers and Conjugated/Olefin Copolymers.

Degree: PhD, Chemistry, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/147712

► Catalyst-transfer polymerization (CTP) is a useful living, chain-growth polymerization method for synthesizing conjugated polymers with targetable molecular weights, narrow dispersities, and controllable copolymer sequences—all properties… (more)

▼ Catalyst-transfer polymerization (CTP) is a useful living, chain-growth polymerization method for synthesizing conjugated polymers with targetable molecular weights, narrow dispersities, and controllable copolymer sequences—all properties that significantly influence their performance in devices. Several phosphine- and N-heterocyclic carbene (NHC)-ligated Ni- and Pd-based precatalysts have been shown to be effective in CTP. One current limitation is that these traditional CTP catalysts lead to nonliving, non-chain-growth behavior when polymerizing complex monomers. Because these monomers are found in high-performing materials, there is a need to identify alternative CTP catalysts. Mechanistic insight has laid the foundation for designing new CTP catalysts. Building off this insight, we have designed and implemented model systems to identify catalysts by understanding their mechanistic behaviors and systematically modifying catalyst structures to improve their chain-growth behavior. In Chapter 1, we describe how each catalyst parameter influences CTP. Ancillary ligands can be used to promote the key intermediate (a metal–arene associative complex) and its reactivity. Reactive ligands can improve catalyst solubility and accelerate initiation. While most CTP catalysts contain nickel, palladium-based catalysts exhibit a higher functional group tolerance and broader substrate scope. Overall, we anticipate that applying the tools and lessons detailed in Chapter 1 to other monomers should facilitate a better “matchmaking” process that will lead to new CTPs. Few studies have elucidated the impact of these identities on the stability and reactivity of the key intermediate, especially under polymerization-relevant conditions. In Chapter 2, we developed a simple experiment to identify catalyst stability and ring-walking ability using in situ-generated polymers. The combined results show that the ancillary ligand, metal, and polymer identity all play a crucial role. While each catalyst studied walks efficiently over large distances in poly(thiophene), the trends observed for poly(phenylene) highlight the differing roles of transition metal and ancillary ligand identities. The insights gained herein should be useful for extending CTP to other monomer and copolymer scaffolds. Recently, diimine-ligated Ni complexes have been employed for CTP; however, in most cases nonliving pathways become dominant at high monomer conversions and/or low catalyst loading. In Chapter 3, we report an alternative Ni diimine catalyst that polymerizes 3- hexylthiophene in a chain-growth manner at low catalyst loading and high monomer conversion. In addition, we elucidate the chain-growth mechanism as well as one chain-transfer pathway. Overall, these studies provide insight into the mechanism of conjugated polymer synthesis mediated by Ni diimine catalysts. There are a limited number of living polymerization methods for generating copolymers from dissimilar monomers. In Chapter 4 we describe a model system to identify potential precatalysts for… Advisors/Committee Members: McNeil, Anne Jennifer (committee member), Kim, Jinsang (committee member), Matzger, Adam J (committee member), Sanford, Melanie S (committee member).

Subjects/Keywords: Catalyst-Transfer Polymerization; Nickel; Palladium; Mechanism; Copolymer; Diimine; Chemistry; Science

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Leone, A. (2018). Using Mechanistic Insight to Develop Living Polymerizations for Conjugated Homopolymers and Conjugated/Olefin Copolymers. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/147712

Chicago Manual of Style (16^th Edition):

Leone, Amanda. “Using Mechanistic Insight to Develop Living Polymerizations for Conjugated Homopolymers and Conjugated/Olefin Copolymers.” 2018. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/147712.

MLA Handbook (7^th Edition):

Leone, Amanda. “Using Mechanistic Insight to Develop Living Polymerizations for Conjugated Homopolymers and Conjugated/Olefin Copolymers.” 2018. Web. 12 Apr 2021.

Vancouver:

Leone A. Using Mechanistic Insight to Develop Living Polymerizations for Conjugated Homopolymers and Conjugated/Olefin Copolymers. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/147712.

Council of Science Editors:

Leone A. Using Mechanistic Insight to Develop Living Polymerizations for Conjugated Homopolymers and Conjugated/Olefin Copolymers. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/147712

University of Michigan

7. Li, Anton W. Morphological Design of Conjugated Polymer Thin Films for Charge Transport and Energy Conversion.

Degree: PhD, Materials Science and Engineering, 2016, University of Michigan

URL: http://hdl.handle.net/2027.42/120716

► Conjugated polymers hold great promise as a versatile class of materials for a wide range of optoelectronic applications, but unlocking their full potential requires deeper… (more)

▼ Conjugated polymers hold great promise as a versatile class of materials for a wide range of optoelectronic applications, but unlocking their full potential requires deeper understanding of relationships between their complex structure and physical properties at multiple length scales. For polymer/fullerene blends used for thin film photovoltaics, controlling the “bulk heterojunction” morphology is of paramount importance to solar cell performance. By incorporating a small amount of an interfacially-active copolymer, the nano-scale phase separation was enhanced, generating more favorable pathways for transport and collection of photo-generated charges. The copolymer also enriched the region near the electrode, shifting the interfacial work function and suppressing surface recombination. Together these effects yielded up to a 20% increase in power conversion efficiencies. Even as pure components, conjugated polymers exhibit very diverse morphologies. By aligning the polymer chains, it is possible to borrow their molecular anisotropy and exploit it at the macroscopic level. Highly-aligned films were fabricated consisting of fibers with uniaxial orientation over centimeter-scale regions, and it was experimentally demonstrated that chain alignment could enable photo-excited charges to migrate distances over 400 µm. The measured anisotropy of optical properties, photocurrent migration, and carrier mobilities are all correlated to the morphology of the aligned films. As a contrasting yet complementary study, the effect of structural disorder on different transport mechanisms/regimes was investigated. To this end, a novel vacuum deposition technique was used to fabricate conjugated polymer films with unique globular morphologies. Despite being more disordered, vacuum-deposited thin film transistors (0.0083 cm²/V*s) exhibited comparable in-plane mobilities to spin-cast analogues (0.0055 cm²/V*s). Their out-of-plane mobilities, on the other hand, were nearly an order of magnitude lower. The seemingly contradictory results were rationalized in terms of the morphologies and carrier densities at interfaces versus within the bulk. Through different approaches to exploring various aspects of structure-property relationships in conjugated polymers, the work presented in this dissertation yields important insights for the future design and application of these materials. Advisors/Committee Members: Green, Peter F (committee member), Zhong, Zhaohui (committee member), Kim, Jinsang (committee member), Tuteja, Anish (committee member).

Subjects/Keywords: conjugated polymer; polymer morphology; photovoltaics; organic electronics; thin films; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Li, A. W. (2016). Morphological Design of Conjugated Polymer Thin Films for Charge Transport and Energy Conversion. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/120716

Chicago Manual of Style (16^th Edition):

Li, Anton W. “Morphological Design of Conjugated Polymer Thin Films for Charge Transport and Energy Conversion.” 2016. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/120716.

MLA Handbook (7^th Edition):

Li, Anton W. “Morphological Design of Conjugated Polymer Thin Films for Charge Transport and Energy Conversion.” 2016. Web. 12 Apr 2021.

Vancouver:

Li AW. Morphological Design of Conjugated Polymer Thin Films for Charge Transport and Energy Conversion. [Internet] [Doctoral dissertation]. University of Michigan; 2016. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/120716.

Council of Science Editors:

Li AW. Morphological Design of Conjugated Polymer Thin Films for Charge Transport and Energy Conversion. [Doctoral Dissertation]. University of Michigan; 2016. Available from: http://hdl.handle.net/2027.42/120716

8. Smith, Mitchell. Expanding the Utility of Catalyst-Transfer Polymerization.

Degree: PhD, Chemistry, 2017, University of Michigan

URL: http://hdl.handle.net/2027.42/137170

► Conjugated polymers are electronically tunable semiconductors that can be solution-processed onto flexible substrates, making them valuable materials for electronic devices including bulk-heterojunction (BHJ) solar cells.… (more)

▼ Conjugated polymers are electronically tunable semiconductors that can be solution-processed onto flexible substrates, making them valuable materials for electronic devices including bulk-heterojunction (BHJ) solar cells. Historical syntheses of π-conjugated polymers have been step-growth; however, the development of catalyst-transfer polymerization (CTP) has led to precise control over molecular weight, dispersity, and copolymer sequence. To date, CTP has not been widely adopted to prepare materials for devices. This thesis describes our efforts to improve the utility of CTP through developing new catalysts for the controlled synthesis of pi-conjugated polymers, investigating the mechanism of non-living behavior in CTP of challenging substrates, and understanding the impact of dispersity on thin-film morphology. Chapter 1 provides an overview of BHJ solar cells and a brief history of catalyst-transfer polymerization. Investigations of the mechanism of CTP are described, with a focus on the purported key intermediate, a catalyst-polymer π-complex formed following reductive elimination. We focus on the monomer scope, illustrating the current limitations, and connect the challenge posed by electron-deficient monomers to the proposed mechanism. The catalyst scope, and efforts to expand CTP catalysis to alternate ancillary ligand scaffolds, is also described. Chapter 2 describes the use of a palladium-N-heterocyclic carbene catalyst for CTP. We observe the controlled polymerization of both phenylene and thiophene monomers, while the polymerization of fluorene is nonliving. Excitingly, block copolymers of thiophene and phenylene can be prepared regardless of addition order, indicating more complicated copolymer sequences could be achieved. We suggest further investigation of this catalyst scaffold as an alternate path for new CTP conditions. Chapter 3 describes mechanistic studies into the CTP of thiazole, an electron-deficient analogue of thiophene. Using reaction-discovery calculations, we identify a facile pathway for chain-transfer to monomer. The chain-transfer pathway is enabled by preferential association of the catalyst following reductive elimination, inhibiting catalyst transfer to the chain-end. We selectively inhibit this chain-transfer pathway and promote chain propagation via ancillary ligand modification. End-group analysis confirms the greatly enhanced living character of the polymerization. We also report the autopolymerization of certain thiazole Grignard monomers. Chapter 4 reports initial investigations into the role of dispersity on thin-film morphology. The existing literature on dispersity’s impact is in poor agreement, and we believe that the control CTP provides over molecular weight is necessary to properly investigate this question. We utilize two methods to vary dispersity, preparing three series of polymer samples with similar Mn or Mw. Using UV-vis spectroscopy and optical microscopy, we find that fullerene aggregation increases with dispersity, and tentatively attribute this to the… Advisors/Committee Members: McNeil, Anne Jennifer (committee member), Kim, Jinsang (committee member), Matzger, Adam J (committee member), Wolfe, John P (committee member).

Subjects/Keywords: catalyst-transfer polymerization; conjugated polymers; organic photovoltaics; Chemistry; Science

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Smith, M. (2017). Expanding the Utility of Catalyst-Transfer Polymerization. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/137170

Chicago Manual of Style (16^th Edition):

Smith, Mitchell. “Expanding the Utility of Catalyst-Transfer Polymerization.” 2017. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/137170.

MLA Handbook (7^th Edition):

Smith, Mitchell. “Expanding the Utility of Catalyst-Transfer Polymerization.” 2017. Web. 12 Apr 2021.

Vancouver:

Smith M. Expanding the Utility of Catalyst-Transfer Polymerization. [Internet] [Doctoral dissertation]. University of Michigan; 2017. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/137170.

Council of Science Editors:

Smith M. Expanding the Utility of Catalyst-Transfer Polymerization. [Doctoral Dissertation]. University of Michigan; 2017. Available from: http://hdl.handle.net/2027.42/137170

University of Michigan

9. Shalev, Olga. Molecular Organic Materials Properties and Controlled Film Growth via Organic Vapor Jet Printing.

Degree: PhD, Materials Science and Engineering, 2016, University of Michigan

URL: http://hdl.handle.net/2027.42/135892

► This dissertation describes advances in printing small molecular organic compounds having important applications, including two with major societal impact: the additive patterning of organic semiconductors… (more)

▼ This dissertation describes advances in printing small molecular organic compounds having important applications, including two with major societal impact: the additive patterning of organic semiconductors and the continuous production of pharmaceutics. Rapid progress in research and development of organic electronics has resulted in many exciting discoveries and applications, including OLEDs and OPVs. Small molecular organic optoelectronic devices are usually multilayer films and patterns comprised of sharp interfaces and highly pure materials. Solvent-based deposition and patterning methods compromise the purity and interface sharpness, calling for solvent-free methods. Vacuum thermal evaporation is a common technique used currently, with inherent limits for scale-up. Instead, organic vapor jet printing (OVJP) is proposed, enabling solvent-free patterning of molecular semiconductors. In OVJP, a carrier gas is used to drive collimated flow, resulting in additive patterning, while preserving advantages of vacuum thermal evaporation. For process and equipment design and scale-up, knowing the evaporation properties of organic semiconductors, and having the ability to predict film morphology formation for a range of process conditions used in devices is crucial. To address these needs, we studied the thermophysical properties of small molecular organic compounds and demonstrated a new predictive relationship between material density and sublimation enthalpy. We then applied this knowledge to enhance patterning resolution and materials utilization, using flow simulations to design new evaporation systems that achieve micrometer-scale patterning resolution. The gas-to-solid phase transition in OVJP was studied, identifying process conditions for unique surface morphologies, with potentially useful properties. A phase diagram was developed that predicts surface morphology as a function of molecular properties and deposition conditions. These discoveries were then used to produce films of organic compounds with enhanced dissolution kinetics, which are found to be beneficial for many medical applications. OVJP technique was shown to break fundamental barriers for the deployment of some drug candidates by enhancing their dissolution kinetics by orders of magnitude, while enabling novel drug delivery systems, such as medicines deposited onto microneedles, patches, biodegradable polymers. Direct in vitro treatment of breast and ovarian cancer cell cultures in aqueous media, by tamoxifen films shows significantly improved bioavailability as compared to powders. Advisors/Committee Members: Shtein, Max (committee member), Lu, Wei (committee member), Forrest, Stephen R (committee member), Kim, Jinsang (committee member).

Subjects/Keywords: Organic vapor jet printing; Evaporation enthalpy of small organic semiconductors; Vapor pressure of small organic semiconductors; Growth of small organic molecular films; Patterning resolution of small organic molecular films; Printing of small molecular pharmaceuticals; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Shalev, O. (2016). Molecular Organic Materials Properties and Controlled Film Growth via Organic Vapor Jet Printing. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/135892

Chicago Manual of Style (16^th Edition):

Shalev, Olga. “Molecular Organic Materials Properties and Controlled Film Growth via Organic Vapor Jet Printing.” 2016. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/135892.

MLA Handbook (7^th Edition):

Shalev, Olga. “Molecular Organic Materials Properties and Controlled Film Growth via Organic Vapor Jet Printing.” 2016. Web. 12 Apr 2021.

Vancouver:

Shalev O. Molecular Organic Materials Properties and Controlled Film Growth via Organic Vapor Jet Printing. [Internet] [Doctoral dissertation]. University of Michigan; 2016. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/135892.

Council of Science Editors:

Shalev O. Molecular Organic Materials Properties and Controlled Film Growth via Organic Vapor Jet Printing. [Doctoral Dissertation]. University of Michigan; 2016. Available from: http://hdl.handle.net/2027.42/135892

University of Michigan

10. Tan, Azariah. Summary of Dissertation Recitals Three Programs of Piano Music.

Degree: AMU, Music: Performance, 2016, University of Michigan

URL: http://hdl.handle.net/2027.42/147555

► Three piano recitals were given in lieu of a written dissertation. In this series of recitals I have presented three programs covering works from the… (more)

Subjects/Keywords: THREE PROGRAMS OF PIANO MUSIC; Music and Dance; Arts

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Tan, A. (2016). Summary of Dissertation Recitals Three Programs of Piano Music. (Thesis). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/147555

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Tan, Azariah. “Summary of Dissertation Recitals Three Programs of Piano Music.” 2016. Thesis, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/147555.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Tan, Azariah. “Summary of Dissertation Recitals Three Programs of Piano Music.” 2016. Web. 12 Apr 2021.

Vancouver:

Tan A. Summary of Dissertation Recitals Three Programs of Piano Music. [Internet] [Thesis]. University of Michigan; 2016. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/147555.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Tan A. Summary of Dissertation Recitals Three Programs of Piano Music. [Thesis]. University of Michigan; 2016. Available from: http://hdl.handle.net/2027.42/147555

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Michigan

11. Vazquez, Ricardo. Characterizing the Excited State Dynamics of Organic Materials for Efficient Energy Conversion: from Current to Photons and Vice-Versa.

Degree: PhD, Chemistry, 2019, University of Michigan

URL: http://hdl.handle.net/2027.42/153365

► The use of organic semiconductor (OSC) materials for optoelectronic applications such as display technologies, consumer electronics, energy-storage, and photovoltaic conversion has drawn academic and industrial… (more)

▼ The use of organic semiconductor (OSC) materials for optoelectronic applications such as display technologies, consumer electronics, energy-storage, and photovoltaic conversion has drawn academic and industrial interest in recent years. The OSC rise in popularity and demand is due to their multiple advantageous properties over their inorganic counterparts. Some of these OSC properties are their ease of device processability, flexibility, and cost-efficiency. In addition, their synthetic flexibility allows for subtle modifications in their structure so their optical and electrochemical properties could be systematically tuned. The molecular structure dictates their function, therefore, fundamental understanding on how modulating their chemical structures will tune their opto-electrical properties is imperative to optimize their optoelectronic performance. In this dissertation, ultrafast spectroscopy and nonlinear optical methods were used to probe the excited state dynamics of OSC materials with 1) thermally activated delayed fluorescence (TADF) characteristics, and 2) light harvesting and low-bandgap materials for bulk heterojunction (BHJ) architectures. The former is a mechanism used for enhancing the efficiency of the third-generation organic light emitting diodes (OLEDs), while the latter composed the active layer of the third generation organic photovoltaic (OPV) devices. TADF is the idea that dark triplet excitons can be converted into emissive singlet exciton via a reverse intersystem crossing (rISC) mechanism, which the rISC is prompted by the combination of room thermal energy with the small energy gap between the singlet-triplet manifolds (ΔEST). This mechanism has been implemented into OLEDs. However, one of the major challenges hampering their commercialization is the lack of seep understanding on the overall TADF mechanism in such systems. Throughout the course of this thesis, the photophysical properties of multiple TADF emitters are elucidated. In addition, a new optical approach for the direct characterization of the rate of rISC (krISC) is introduced. This new methodology could be used to predict their respective device performances. The krISC in TADF emitters is believed to be critical for reducing the triplet-triplet annihilation (TTA) mechanism that cause efficiency roll-off at high operational voltage. In the case of the active materials for BHJ applications, the optical properties of light harvesting polymers and low-bandgap small molecules for non-fullerene acceptors (NFA) devices are elucidated. Specifically, the influence of heterocycles such as furan and thiophene as linkers on the photophysical properties of light harvesting polymers were probed with and emphasis in their charge transfer properties. These light harvesting polymers were based on benzodifuran (BDF) as the donor and diketopyrrolopyrrole (DPP) as the acceptor. The low-bandgap materials were designed to be acceptor-donor-acceptor ladder-type molecules based on perylene-diimide (PDI) as the acceptor and heteroacenes as the donor.… Advisors/Committee Members: Goodson III, Theodore G (committee member), Kim, Jinsang (committee member), Guo, L Jay (committee member), Zgid, Dominika Kamila (committee member).

Subjects/Keywords: Organic Light Emitting Diodes Based on Thermally Activated Delayed Fluorescence (TADF) Chromophores; Excited State Dynamics; Photovoltaics (BHT), Light Harvesting Polymers, Low-Bandgap Materials, intramolecular Singlet Fission; Chemistry; Science

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Vazquez, R. (2019). Characterizing the Excited State Dynamics of Organic Materials for Efficient Energy Conversion: from Current to Photons and Vice-Versa. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/153365

Chicago Manual of Style (16^th Edition):

Vazquez, Ricardo. “Characterizing the Excited State Dynamics of Organic Materials for Efficient Energy Conversion: from Current to Photons and Vice-Versa.” 2019. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/153365.

MLA Handbook (7^th Edition):

Vazquez, Ricardo. “Characterizing the Excited State Dynamics of Organic Materials for Efficient Energy Conversion: from Current to Photons and Vice-Versa.” 2019. Web. 12 Apr 2021.

Vancouver:

Vazquez R. Characterizing the Excited State Dynamics of Organic Materials for Efficient Energy Conversion: from Current to Photons and Vice-Versa. [Internet] [Doctoral dissertation]. University of Michigan; 2019. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/153365.

Council of Science Editors:

Vazquez R. Characterizing the Excited State Dynamics of Organic Materials for Efficient Energy Conversion: from Current to Photons and Vice-Versa. [Doctoral Dissertation]. University of Michigan; 2019. Available from: http://hdl.handle.net/2027.42/153365

University of Michigan

12. Kim, Taesu. Analysis of Molecular Interaction and Its Effect on Light- Harvesting and Emitting Organic Systems at the Nanoscale.

Degree: PhD, Macromolecular Science & Engineering, 2019, University of Michigan

URL: http://hdl.handle.net/2027.42/153337

► Organic electronics is a branch of modern electronics, and it deals with organic materials, such as polymers or small molecules. Its high flexibility, ease of… (more)

▼ Organic electronics is a branch of modern electronics, and it deals with organic materials, such as polymers or small molecules. Its high flexibility, ease of manufacturing, low cost and environmental impact gathered huge interest from industry and academia. While there have been great progress in the area of organic electronic materials, many challenges limit the potentials of various organic systems. The intrinsic structural and electronic inhomogeneity of the solid state aggregates of organic molecules limit their performance and lower their stability. Mismatch between the light absorption and the exciton transport length in organic photovoltaic cells is the critical point of the issue. To solve this problem a better understanding of the excitation transport properties on a local level is essential. However it is difficult to probe the exited dynamics due to fast decay and short transport length of exciton. To better investigate these materials, superior spatial and temporal resolved spectroscopy is essential. In this dissertation, various spectroscopic methods have been introduced to analyze the exciton dynamics in local level. Interferometric two-photon near-field scanning optical microscopy has been introduced to show the organic macromolecular and aggregate systems assembled in different molecular structural orientation. A focus will be placed on the combination of fs-laser interferometry and NSOM microscopy. ~100fs temporal and ~50nm spatial resolution of the system efficiently highlight the structure-functional relationship, discriminate the heterogeneity and measure the coherent excited state dynamic of the molecular system aggregates. Additionally, the ultra-fast excited state behavior of selected organic electronic materials has been studied using fluorescence upconversion and transient absorption spectroscopy. These investigations inform us of how these photophysical interactions occur in several systems, including light -harvesting and -emitting systems. Advisors/Committee Members: Goodson III, Theodore G (committee member), Kim, Jinsang (committee member), McCrory, Charles (committee member), Robertson, Richard E (committee member).

Subjects/Keywords: NSOM; Ultra fast spectroscopy; Coherent energy transport; OLED; Organic Photovoltaic; TADF; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kim, T. (2019). Analysis of Molecular Interaction and Its Effect on Light- Harvesting and Emitting Organic Systems at the Nanoscale. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/153337

Chicago Manual of Style (16^th Edition):

Kim, Taesu. “Analysis of Molecular Interaction and Its Effect on Light- Harvesting and Emitting Organic Systems at the Nanoscale.” 2019. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/153337.

MLA Handbook (7^th Edition):

Kim, Taesu. “Analysis of Molecular Interaction and Its Effect on Light- Harvesting and Emitting Organic Systems at the Nanoscale.” 2019. Web. 12 Apr 2021.

Vancouver:

Kim T. Analysis of Molecular Interaction and Its Effect on Light- Harvesting and Emitting Organic Systems at the Nanoscale. [Internet] [Doctoral dissertation]. University of Michigan; 2019. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/153337.

Council of Science Editors:

Kim T. Analysis of Molecular Interaction and Its Effect on Light- Harvesting and Emitting Organic Systems at the Nanoscale. [Doctoral Dissertation]. University of Michigan; 2019. Available from: http://hdl.handle.net/2027.42/153337

13. Souther, Kendra. Advancing Conjugated Polymer Synthesis Through Catalyst Design.

Degree: PhD, Chemistry, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/146125

► Catalyst-transfer polymerization (CTP) is a living, chain-growth method for synthesizing conjugated polymers, which are attractive materials for organic electronics. What separates CTP from traditional cross-coupling… (more)

▼ Catalyst-transfer polymerization (CTP) is a living, chain-growth method for synthesizing conjugated polymers, which are attractive materials for organic electronics. What separates CTP from traditional cross-coupling polymerizations is a metal–polymer π-complex that enables the catalyst to stay associated to the growing polymer chain. This association yields polymers with targeted molecular weights, narrow dispersities, and tunable sequences. However, the utility of CTP is limited by a narrow monomer scope, wherein the most desirable polymers remain inaccessible via controlled methods. This thesis aims to advance CTP by designing catalysts capable of widening monomer pairings for block copolymers, exploring ligand electronics in designing an optimal CTP catalyst for previously inaccessible monomers, and optimizing a new user-friendly CTP method. Chapter 1 briefly summarizes CTP with a focus on how understanding polymerization mechanisms can facilitate catalyst design. Specifically, how exploiting the metal-π complex has led to expanded, albeit limited monomer scope, and new copolymer sequences. The major conclusions of chapters 2–5 and our efforts to expand CTP catalyst scope are briefly outlined followed by the implications of this work on future CTP systems. Chapter 2 reports the trials and tribulations of designing a single catalyst to perform two sequential, living polymerizations to access thiophene/olefin block copolymers in a one-pot synthesis. Lessons learned include the influence of catalyst reactive ligand and cocatalyst identity on successful thiophene polymerization as well as the inhibitory nature of olefins on thiophene polymerization, requiring olefin monomer removal to induce a switch-in-mechanisms. While a small amount of copolymer was synthesized, the major products were undesired homopolymer. We attributed these homopolymers to a high-barrier reductive elimination when the catalyst switches mechanisms and subsequent chain-transfer during thiophene polymerization. This work highlights the need to identify conditions that facilitate living behavior for both polymerizations as well as promotes efficient cross-propagation. Chapter 3 describes efforts to design catalysts for CTP that expand monomer scope by tuning ligand electronics to stabilize the metal-π complex. A pyrrolidinyl-based bisphosphine precatalyst was explored in poly(thiophene) and poly(hexylesterthiophene) synthesis and yields polymers with targeted molecular weights as well as high end-group fidelity, suggesting this newly designed catalyst forms a stabilized metal-π complex. While poly(phenylene) synthesis was attempted, gel permeation chromatography revealed a multimodal polymer trace, suggesting multiple catalytic species in the polymerization and an uncontrolled reaction. This catalyst should be further explored in polymerizing previously inaccessible monomers, whose polymerizations are often marred by chain-transfer events. Chapter 4 describes efforts towards developing a more user-friendly CTP. An NHC-ligated palladium… Advisors/Committee Members: McNeil, Anne Jennifer (committee member), Kim, Jinsang (committee member), Wolfe, John P (committee member), Zimmerman, Paul (committee member).

Subjects/Keywords: catalyst-transfer polymerization, conjugated polymers, polythiophene, chain-growth; Chemistry; Science

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Souther, K. (2018). Advancing Conjugated Polymer Synthesis Through Catalyst Design. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/146125

Chicago Manual of Style (16^th Edition):

Souther, Kendra. “Advancing Conjugated Polymer Synthesis Through Catalyst Design.” 2018. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/146125.

MLA Handbook (7^th Edition):

Souther, Kendra. “Advancing Conjugated Polymer Synthesis Through Catalyst Design.” 2018. Web. 12 Apr 2021.

Vancouver:

Souther K. Advancing Conjugated Polymer Synthesis Through Catalyst Design. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/146125.

Council of Science Editors:

Souther K. Advancing Conjugated Polymer Synthesis Through Catalyst Design. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/146125

University of Michigan

14. Lee, Ji Seok. Molecular Design and Self-assembly of Polydiacetylene for Biosensors and Sensor Arrays.

Degree: PhD, Macromolecular Science & Engineering, 2011, University of Michigan

URL: http://hdl.handle.net/2027.42/86557

► The major themes of this dissertation are to develop molecular design principles of sensory polydiacetylene (PDA) and establish efficient chemo/biosensor device fabrication strategies for selective… (more)

▼ The major themes of this dissertation are to develop molecular design principles of sensory polydiacetylene (PDA) and establish efficient chemo/biosensor device fabrication strategies for selective and sensitive detection of target analytes. We rationally designed probe-modified PDA liposomes such a way that analyte binding at the surface-immobilized probes produces steric repulsion that induces the perturbation of the conjugated ene-yne backbone of PDA and generates optical color change from blue to read and red fluorescence emission, as well. PDA liposome microarray to detect potassium was first developed to utilize the strong intra-repulsion strain caused by the formation of a potassium/aptamer G-quadruplex structure. We further expanded the design principle to a mercury detection system with superior immobilization functionality. In this work the probe DNA was microarrayed onto a glass substrate having immobilized PDA liposomes, opening up a possibility to build high throughput microarray having multiple probe molecules for spontaneous multiple detections. Molecular recognition through hydrogen bonding was also investigated in our colorimetric melamine sensor development. PDA molecules were modified with cyanuric acid that forms multiple hydrogen bondings with melamine molecules. The hydrogen bonding between melamine molecules and the cyanuric acids resulted in a notable color transition as well as red fluorescence emission due to the stress by intra-liposomal repulsion and inter-liposomal aggregation. The intra- and inter-liposomal interactions were also applied to the development of a convenient nerve gas detection system. PDA liposomes, modified with oxime units for selective interaction with nerve agents, were embedded into solid membrane filters for convenient use. Hydrophobic organophosphorous (OP) molecules induced large intra repulsion and also massive inter-liposomal aggregation by reacting with the oxime at the surface of the PDA liposomes. Multi-targeting PDA sensory system was also developed by encapsulating PDA liposomes having different probes into a multi-faced micron-size agarose beads to provide selective/sensitive multiple analytes detection. In addition to biosensor development, a functional PDA liposome system was investigated for immunofluorescence labeling application. The dye-loaded PDA liposomes with a receptor visualized patterns by producing dual green/red fluorescence emission. A novel PDA system having light-driven color change capability was also developed and its photochromism was demonstrated. Advisors/Committee Members: Kim, Jinsang (committee member), Guo, L. Jay (committee member), Kuroda, Kenichi (committee member), Martin, David C. (committee member).

Subjects/Keywords: Polydiacetylene Liposomes Based Chemo/Biosensor; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lee, J. S. (2011). Molecular Design and Self-assembly of Polydiacetylene for Biosensors and Sensor Arrays. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/86557

Chicago Manual of Style (16^th Edition):

Lee, Ji Seok. “Molecular Design and Self-assembly of Polydiacetylene for Biosensors and Sensor Arrays.” 2011. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/86557.

MLA Handbook (7^th Edition):

Lee, Ji Seok. “Molecular Design and Self-assembly of Polydiacetylene for Biosensors and Sensor Arrays.” 2011. Web. 12 Apr 2021.

Vancouver:

Lee JS. Molecular Design and Self-assembly of Polydiacetylene for Biosensors and Sensor Arrays. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/86557.

Council of Science Editors:

Lee JS. Molecular Design and Self-assembly of Polydiacetylene for Biosensors and Sensor Arrays. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/86557

University of Michigan

15. Hall, Ariana. Catalyst and Reaction Development in Conjugated Polymer Synthesis.

Degree: PhD, Chemistry, 2017, University of Michigan

URL: http://hdl.handle.net/2027.42/138796

► Conjugated polymers are lightweight, flexible, solution-processible materials which can be used in organic electronic devices, including photovoltaics and light-emitting diodes. Catalyst-transfer polymerization (CTP) is a… (more)

▼ Conjugated polymers are lightweight, flexible, solution-processible materials which can be used in organic electronic devices, including photovoltaics and light-emitting diodes. Catalyst-transfer polymerization (CTP) is a chain-growth method for synthesize conjugated polymers with targeted molecular weight and sequence, as well as narrow dispersity. Several factors continue to limit the utility of CTP. Slow precatalyst initiation leads to broad dispersity and limited sequence control. Furthermore, the monomer scope of CTP is limited, especially for electron-deficient monomers. The highest performing polymers in photovoltaic devices are still synthesized by step-growth polymerizations. This thesis describes our efforts to address both limitations of CTP by designing new precatalysts which undergo fast initiation, using model reactions to screen catalysts to expand CTP scope, and finally, to develop new, non-CTP chain-growth syntheses of conjugated polymers through single-electron reactions. Chapter 1 provides a history of CTP for conjugated polymer synthesis. It describes progress that has been made in precatalyst design to improve dispersity and enhance initiation. We then discuss the use of small-molecule screens to identify catalysts for CTP as a method for expanding the monomer scope. Finally, we briefly introduce the precedent for single-electron reactions, both radical and electrochemical, for conjugated polymer synthesis and explain our proposal to develop chain-growth syntheses by modifying these methods. Chapter 2 reports our design of a new precatalyst which has faster initiation than propagation. It describes our development of a new method for measuring initiation rates during polymerization, as well as our discovery that adding triphenylphosphine to a polymerization and incorporating a trifluoroethoxy group into a precatalyst both affected initiation rates. Chapter 3 describes our efforts to identify catalysts and reaction conditions for CTP of phenylene-ethynylene by using a small-molecule reaction to probe for catalyst association by looking at mono-coupling versus di-coupling. It explains our discovery that small-molecule systems, which we and others have previously used, can have false positives when there are large reactivity differences between substrates, and proposes additional experiments to increase the accuracy of such models for predicting CTP. Chapter 4 describes our efforts to synthesize conjugated polymers through single-electron reactions rather than CTP. We present the precedent for conjugated polymer synthesis via SRN1 reactions, and our attempts to expand the monomer scope to several monomers used in organic photovoltaics. It further explains the history of step-growth electropolymerizations and our efforts to use indirect electrolysis to develop a chain-growth electropolymerization for conjugated polymers. We successfully synthesized one conjugated polymer using a perylene diimide mediator. Chapter 5 summarizes our progress in catalyst and reaction development for conjugated… Advisors/Committee Members: McNeil, Anne Jennifer (committee member), Kim, Jinsang (committee member), Sanford, Melanie S (committee member), Wolfe, John P (committee member).

Subjects/Keywords: conjugated polymer synthesis; Chemistry; Science

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hall, A. (2017). Catalyst and Reaction Development in Conjugated Polymer Synthesis. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/138796

Chicago Manual of Style (16^th Edition):

Hall, Ariana. “Catalyst and Reaction Development in Conjugated Polymer Synthesis.” 2017. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/138796.

MLA Handbook (7^th Edition):

Hall, Ariana. “Catalyst and Reaction Development in Conjugated Polymer Synthesis.” 2017. Web. 12 Apr 2021.

Vancouver:

Hall A. Catalyst and Reaction Development in Conjugated Polymer Synthesis. [Internet] [Doctoral dissertation]. University of Michigan; 2017. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/138796.

Council of Science Editors:

Hall A. Catalyst and Reaction Development in Conjugated Polymer Synthesis. [Doctoral Dissertation]. University of Michigan; 2017. Available from: http://hdl.handle.net/2027.42/138796

University of Michigan

16. Song, Byeongseop. Controlling Thin-film Morphology and Incorporating Novel Semiconducting Molecules toward High Performance Organic Optoelectronic Devices.

Degree: PhD, Electrical Engineering, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/144195

► Organic optoelectronic devices have been widely used in display, energy-storage, and consumer electronics. Insightful understanding on material properties, device architecture, and fabrication processes is inevitable… (more)

▼ Organic optoelectronic devices have been widely used in display, energy-storage, and consumer electronics. Insightful understanding on material properties, device architecture, and fabrication processes is inevitable to improve the performance of organic optoelectronic devices. My PhD research focuses on improving the performance of organic photovoltaics (OPV) and organic light-emitting diode (OLED) through the systematic processing and material design. The first part of the dissertation describes how to construct a highly conductive morphology of mixed donor:acceptor heterojunction. Organic vapor phase deposition (OVPD) was utilized to enhance crystallinity of C70 acceptor in the mixed tetraphenyldibenzoperiflanthen (DBP):C70 thin-film. Forming the face-center-cubic (fcc) structure of C70 facilitated charge extraction, thereby improving fill factor (FF) of the corresponding OPVs. The second part presents the study on the morphological stability and reliability of OPVs. The cathode buffer, bathophenanthroline (BCP), undergoes significant morphological degradation. This morphological degradation was successfully suppressed by making the underlying DBP:C70 layer rougher via the moving N2 carrier gas in OVPD. The open-circuit voltage (Voc) of the obtained heterojunction OPVs of DBP:C70 grown by OVPD experienced a negligible drop (< 3 % change) while the equivalent OPVs grown by VTE showed a significant decrease in Voc from 0.91±0.01 V to 0.74±0.01 after 1 Sun illumination for 250 h. The third part explains a more precise way to control the morphology of organic mixed layer. It was found that increase in the growth pressure of OVPD induced reorganization of molecules to form the equilibrium morphology. The morphology of the electron-filtering buffer layer of 3,5,3′,5′-tetra(m-pyrid-3-yl)phenyl[1,1′]biphenyl (BP4mPy):C60 was optimized to achieve the highest electron mobility by means of the control of the growth pressure. Consequently, the resulting OPVs with optimized BP4mPy:C60 buffer showed FF = 0.65±0.01 and a much higher PCE = 8.0±0.2 % compared to PCE = 6.6±0.2 % of the equivalent OPVs with the same composition buffer layer grown by VTE. The fourth part summarizes the effects of the inclusion of novel block-copolymers on the performance of the polymer bulk-heterojunction photovoltaic cells. The block-copolymers were composed of thiophene units with and without a dangling phenyl-C61-butyric acid methyl ester (PCBM) side chain. The added copolymer into the poly(3-hexylthiophene) (P3HT): PCBM active layer resulted in greatly improved thermal stability of P3HT:PCBM. Furthermore, electron conductivity also increased since the fullerene units of the copolymers contribute to the formation of a percolation pathway for electron transport. While PCE of conventional P3HT:PCBM bulk-heterojunction solar cells decreases significantly from 2.6±0.2 to 1.2±0.2% after 90-min of thermal annealing, the equivalent OPVs with the copolymer shows a much smaller decrease in PCE from 3.1±0.2% to 2.7±0.2%. The last section… Advisors/Committee Members: Guo, L Jay (committee member), Kim, Jinsang (committee member), McNeil, Anne Jennifer (committee member), Phillips, Jamie Dean (committee member).

Subjects/Keywords: Organic optoelectronic devices (OLED, OPV); Performance and reliability of organic semiconductor devices; Organic thin-film growth; crystallinity of organic thin-film; purely organic phosphor; Electrical Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Song, B. (2018). Controlling Thin-film Morphology and Incorporating Novel Semiconducting Molecules toward High Performance Organic Optoelectronic Devices. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/144195

Chicago Manual of Style (16^th Edition):

Song, Byeongseop. “Controlling Thin-film Morphology and Incorporating Novel Semiconducting Molecules toward High Performance Organic Optoelectronic Devices.” 2018. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/144195.

MLA Handbook (7^th Edition):

Song, Byeongseop. “Controlling Thin-film Morphology and Incorporating Novel Semiconducting Molecules toward High Performance Organic Optoelectronic Devices.” 2018. Web. 12 Apr 2021.

Vancouver:

Song B. Controlling Thin-film Morphology and Incorporating Novel Semiconducting Molecules toward High Performance Organic Optoelectronic Devices. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/144195.

Council of Science Editors:

Song B. Controlling Thin-film Morphology and Incorporating Novel Semiconducting Molecules toward High Performance Organic Optoelectronic Devices. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/144195

University of Michigan

17. Povlich, Laura K. Bio-Functionalized and Biomimetic Conjugated Polymers for Interfacing Prosthetic Devices with Neural Tissue.

Degree: PhD, Macromolecular Science & Engineering, 2011, University of Michigan

URL: http://hdl.handle.net/2027.42/89771

► Conjugated polymers, such as poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy), have been developed as effective materials for interfacing prosthetic device electrodes with neural tissue. These polymers,… (more)

▼ Conjugated polymers, such as poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy), have been developed as effective materials for interfacing prosthetic device electrodes with neural tissue. These polymers, which are semi-conducting, provide an improved interface compared to metal electrodes because of their ionic conductivity, relatively soft modulus, low electrical impedance and ability to incorporate biological molecules. Recent focus has been on the development of conjugated polymers that have biological components in order to improve the biological response upon implantation of these electrodes. In this thesis, carboxylic acid-functionalized 3,4-ethylenedioxythiophene (EDOTacid) monomer was synthesized in order to covalently bind peptides to the surface of conjugated polymer films. EDOTacid was copolymerized with EDOT monomer to form stable, electrically conductive copolymer films referred to as PEDOT-PEDOTacid. The peptide GGGGRGDS was bound to PEDOT-PEDOTacid and was used to increase the adhesion of primary rat motor neurons between 3 to 9 times higher than controls, thus demonstrating that the peptide maintained its biological activity. PEDOT-PEDOTacid films have the potential to bind to a number of neural specific peptides that could control the behavior of neurons and vastly improve the performance of implanted electrodes. The research in this thesis also investigated the ability of four different monomers – L-3,4-dihydroxyphenylalanine (L-DOPA), 5,6-dimethoxyindole-2-carboxylic acid (DMICA), 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI) – to form electrochemically polymerized conjugated polymer films that mimic the structure of eumelanin, a type of naturally occurring melanin. One of these polymers, poly(5,6-dimethoxyindole-2-carboxylic acid) (PDMICA), was easy to polymerize and had especially interesting electrochromic and nano-structural features. In addition, PDMICA had a relatively high charge capacity (6.5 mC/cm2) and was not cytotoxic toward cells, making it the best candidate for bio-electrode coatings. Since these films are biomimetic in structure they may produce a less severe immune reaction compared to purely synthetic conjugated polymers. Both PDMICA and PEDOT-PEDOTacid are new materials that could be used in the future to coat prosthetic device electrodes and improve communication and interface between these devices and biological tissue. Advisors/Committee Members: Kim, Jinsang (committee member), Martin, David C. (committee member), Corey, Joseph M. (committee member), Takayama, Shuichi (committee member).

Subjects/Keywords: Conducting Polymers; Biomaterial; Neural Electrode; Melanin; RGD; Brain-device Interface; Biomedical Engineering; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Povlich, L. K. (2011). Bio-Functionalized and Biomimetic Conjugated Polymers for Interfacing Prosthetic Devices with Neural Tissue. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/89771

Chicago Manual of Style (16^th Edition):

Povlich, Laura K. “Bio-Functionalized and Biomimetic Conjugated Polymers for Interfacing Prosthetic Devices with Neural Tissue.” 2011. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/89771.

MLA Handbook (7^th Edition):

Povlich, Laura K. “Bio-Functionalized and Biomimetic Conjugated Polymers for Interfacing Prosthetic Devices with Neural Tissue.” 2011. Web. 12 Apr 2021.

Vancouver:

Povlich LK. Bio-Functionalized and Biomimetic Conjugated Polymers for Interfacing Prosthetic Devices with Neural Tissue. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/89771.

Council of Science Editors:

Povlich LK. Bio-Functionalized and Biomimetic Conjugated Polymers for Interfacing Prosthetic Devices with Neural Tissue. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/89771

18. Golovin, Kevin. Design and Application of Surfaces with Tunable Adhesion to Liquids and Solids.

Degree: PhD, Materials Science and Engineering, 2017, University of Michigan

URL: http://hdl.handle.net/2027.42/138592

► Fouling affects a wide range of industries around the globe. The two main categories of fouling are the unwanted adhesion of solids, and the unwanted… (more)

▼ Fouling affects a wide range of industries around the globe. The two main categories of fouling are the unwanted adhesion of solids, and the unwanted adsorption of liquids. The purpose of this thesis is to understand and design new mechanisms to mitigate fouling. As fouling always occurs at the interface between a surface and the foulant, the main strategy employed in this work is the fabrication of designer coatings that can be applied to any surface, such that the foulant is repelled. In the first half of this dissertation I discuss new methods for reducing the adhesion of ice to surfaces. Ice adhesion routinely hinders many industries world-wide, and to-date there have been few long-term strategies to mitigate ice adhesion. We first design elastomeric coatings exhibiting the lowest ice adhesion strengths ever reported, and formulate a predictive model for the phenomenon of interfacial slippage, such that the ice adhesion strength of any surface can be rationally designed. We then utilize fracture mechanics to design surfaces exhibiting low interfacial toughness with ice, such that the force to remove the accreted ice becomes independent of the iced area. These results contradict the last 70 years of ice-adhesion analysis. One of our new techniques for repelling ice, and solid foulants in general, is the fabrication of liquid-like, covalently grafted monolayers. We show that surfaces treated with these monolayers also exhibit extreme liquid repellency, including the first-ever reported fluorophobic surfaces (i.e. surfaces that repel extremely low surface tension, fluorinated liquids). The second half of this thesis discusses various new ways of repelling a wide variety of different fouling liquids. We fabricate optically transparent surfaces capable of repelling a wide variety of low surface tension liquids. We also design extremely mechanically robust superhydrophobic surfaces that can self-heal after physical and chemical damage. Finally, we utilize some of these water-repellent systems to effectively reduce friction drag in turbulent flow. Advisors/Committee Members: Tuteja, Anish (committee member), Reddy, Pramod Kumar (committee member), Kim, Jinsang (committee member), Thouless, Michael (committee member).

Subjects/Keywords: Icephobic; Superhydrophobic; Omniphobic; Drag reduction; Rubber; Coatings; Materials Science and Engineering; Engineering

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Golovin, K. (2017). Design and Application of Surfaces with Tunable Adhesion to Liquids and Solids. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/138592

Chicago Manual of Style (16^th Edition):

Golovin, Kevin. “Design and Application of Surfaces with Tunable Adhesion to Liquids and Solids.” 2017. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/138592.

MLA Handbook (7^th Edition):

Golovin, Kevin. “Design and Application of Surfaces with Tunable Adhesion to Liquids and Solids.” 2017. Web. 12 Apr 2021.

Vancouver:

Golovin K. Design and Application of Surfaces with Tunable Adhesion to Liquids and Solids. [Internet] [Doctoral dissertation]. University of Michigan; 2017. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/138592.

Council of Science Editors:

Golovin K. Design and Application of Surfaces with Tunable Adhesion to Liquids and Solids. [Doctoral Dissertation]. University of Michigan; 2017. Available from: http://hdl.handle.net/2027.42/138592

19. Zhang, Jin. Probing Structure Function Relationships in Novel Silicon Containing Macromolecules with Nonlinear Optical and Ultra-Fast Spectroscopy.

Degree: PhD, Macromolecular Science and Engineering, 2014, University of Michigan

URL: http://hdl.handle.net/2027.42/107048

► Organic photovoltaics (OPVs) as a relatively novel technology have drawn significant attentions to many scientists during the past few years. Understanding the photophysical properties and… (more)

▼ Organic photovoltaics (OPVs) as a relatively novel technology have drawn significant attentions to many scientists during the past few years. Understanding the photophysical properties and energy transfer processes of the potential candidates is crucial to improving overall OPV device efficiencies and guiding new research of designing novel OPV materials. In this dissertation, nonlinear optical and time resolved methods such as two-photon absorption, time-resolved transient absorption, and fluorescence emission are used to study the nature of charge transfer character, energy transfer processes and charge transfer mechanisms in OPV materials. Two groups of organic macromolecules were investigated: 1) Three sets of chromophore substituted silsesquioxane derivatives were investigated to determine structure function relationships on a molecule basis. Exceptional red shift in emission and large two-photon cross-section found in [NH2vinylStilbeneSiO1.5]8 suggest that charge transfer character could be dramatically enhanced by introducing strong electron donating group to the substituted chromophores. Both steady state photophysical and two-photon absorption study of polyfunctional phenylsilsesquioxanes ([o-RPhSiO1.5]8, [2,5-R2PhSiO1.5]8 and [R3PhSiO1.5]8) indicate that adding additional chromophores in a nanostructure could strengthen the electronic coupling among substituted chromophores and enhance charge transfer character of the entire molecule. Time resolved absorption and emission spectroscopy reveal the excited state dynamics of corner and half ([p-Me2NStilSi(OSiMe)3], [p-Me2NStilSi(OSiMe)]4), as well as cube ([p-Me2NStil8SiO1.5]8). 2) A series of novel oligothiophene-perylene bisimide hybrid (DOTPBI) dendrimers (G0, G1, and G2) were investigated. Results revealed the ability of these molecules to undergo intramolecular fluorescence resonance energy transfer (FRET) from the dendritic oligothiophenes (DOT) to the perylene bismide (PBI) moiety. The delocalization length and the photoinduced electron transfer (PET) rates were investigated as a function of dendrimer generation. An ultra-fast (~200 fs) energy transfer process from the DOT dendron to the PBI core was observed. In the case of the G2 dendrimer, with relatively larger oligothiophene dendrons attached to the bay area of the perylene bisimide, the PBI core is highly twisted and thus loses its electron trapping ability. As a result, among the three generations studied, G1, which has the best two-photon cross section and the most efficient energy transfer, is the best light harvesting material among three samples. Advisors/Committee Members: Goodson, Theodore G. (committee member), Ramamoorthy, Ayyalusamy (committee member), Kim, Jinsang (committee member), Laine, Richard M. (committee member).

Subjects/Keywords: Organic Photovoltaic Materials; Untrafast and Nonlinear Optical Spectroscopy; Energy Transfer; Electron Trasfer; Materials Science and Engineering; Engineering

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zhang, J. (2014). Probing Structure Function Relationships in Novel Silicon Containing Macromolecules with Nonlinear Optical and Ultra-Fast Spectroscopy. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/107048

Chicago Manual of Style (16^th Edition):

Zhang, Jin. “Probing Structure Function Relationships in Novel Silicon Containing Macromolecules with Nonlinear Optical and Ultra-Fast Spectroscopy.” 2014. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/107048.

MLA Handbook (7^th Edition):

Zhang, Jin. “Probing Structure Function Relationships in Novel Silicon Containing Macromolecules with Nonlinear Optical and Ultra-Fast Spectroscopy.” 2014. Web. 12 Apr 2021.

Vancouver:

Zhang J. Probing Structure Function Relationships in Novel Silicon Containing Macromolecules with Nonlinear Optical and Ultra-Fast Spectroscopy. [Internet] [Doctoral dissertation]. University of Michigan; 2014. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/107048.

Council of Science Editors:

Zhang J. Probing Structure Function Relationships in Novel Silicon Containing Macromolecules with Nonlinear Optical and Ultra-Fast Spectroscopy. [Doctoral Dissertation]. University of Michigan; 2014. Available from: http://hdl.handle.net/2027.42/107048

University of Michigan

20. Lee, Jae Yong. Ultra-thin Intrinsic Amorphous Silicon (a-Si) Hybrid Structure with Inorganic/Organic Materials and Its Applications.

Degree: PhD, Electrical Engineering, 2014, University of Michigan

URL: http://hdl.handle.net/2027.42/110489

► The conventional a-Si photovoltaic (PV) has been designed with intrinsic a-Si interfaced with p- and n- type doped layers, total around 40-50 nm. Here, the… (more)

▼ The conventional a-Si photovoltaic (PV) has been designed with intrinsic a-Si interfaced with p- and n- type doped layers, total around 40-50 nm. Here, the intrinsic layer needs to be much thicker than the doped layers in order to maximize the conversion of the photogenerated carriers to electric current. Since the dopants, as intentional impurities, annihilate photogenerated carriers, the doped material should be as thin as possible unless it reduces an internal electric field. Eventually the unwanted carrier recombination with dopants causes light-induced degradation of a-Si PV. In this dissertation, we present studies suggesting removing dopants in a-Si PV for higher internal quantum efficiency as well as previously undiscovered novel PV applications. We propose intrinsic a-Si hybrid structure with inorganic/organic materials for PVs without any doping. The highest average power conversion efficiency of the a-Si hybrid PV is 6.7% by 180 nm-thick undoped a-Si layer. Its current density-voltage (J-V) curve shows the average short circuit current (Jsc) of 13.6 mA/cm2, open circuit voltage (Voc) of 0.77, and fill factor (FF) of 64 %. We also characterize the hybrid cells by capacitance-voltage (C-V) measurement to identify a built-in potential, from 0.7 V to 0.85 V, according to metal oxide Schottky contact at anode. The built-in potential consequently determines Voc of the hybrid cells. We exploit the proposed a-Si hybrid device further by running capacitance-frequency (C-f) measurement in order to quantify the interfacial amount of charge annihilation with regard to varied a-Si thicknesses, thereby affecting Voc ranging from 0.6 V to 0.8 V. The Voc change is also evaluated under concentrated sun condition (1 Sun ~ 7 Sun). Since the a-Si hybrid cell shows FF decrease (68 % to 62 %) with increased a-Si thickness (50 nm to 180 nm), we exploit the ambipolar diffusion length (~ 80 nm) by transient photocurrent and photovoltage responses. Notably, we demonstrate the use of the a-Si hybrid cells for decorative colored PV applications by designing a-Si thickness below ~30 nm, even a few nanometers for semi-transparent PVs. We also suggest applying the ultra-thin a-Si hybrid structure for various photo-sensing applications including large area high-speed photo-detectors. Advisors/Committee Members: Guo, L. Jay (committee member), Kim, Jinsang (committee member), Phillips, Jamie Dean (committee member), Lu, Wei (committee member).

Subjects/Keywords: amorphous silicon solar cell; hybrid photovoltaic; inorganic and organic multi-layers; transparent photodetectors; decorative power generating panels; Photon management; Electrical Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lee, J. Y. (2014). Ultra-thin Intrinsic Amorphous Silicon (a-Si) Hybrid Structure with Inorganic/Organic Materials and Its Applications. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/110489

Chicago Manual of Style (16^th Edition):

Lee, Jae Yong. “Ultra-thin Intrinsic Amorphous Silicon (a-Si) Hybrid Structure with Inorganic/Organic Materials and Its Applications.” 2014. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/110489.

MLA Handbook (7^th Edition):

Lee, Jae Yong. “Ultra-thin Intrinsic Amorphous Silicon (a-Si) Hybrid Structure with Inorganic/Organic Materials and Its Applications.” 2014. Web. 12 Apr 2021.

Vancouver:

Lee JY. Ultra-thin Intrinsic Amorphous Silicon (a-Si) Hybrid Structure with Inorganic/Organic Materials and Its Applications. [Internet] [Doctoral dissertation]. University of Michigan; 2014. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/110489.

Council of Science Editors:

Lee JY. Ultra-thin Intrinsic Amorphous Silicon (a-Si) Hybrid Structure with Inorganic/Organic Materials and Its Applications. [Doctoral Dissertation]. University of Michigan; 2014. Available from: http://hdl.handle.net/2027.42/110489

University of Michigan

21. Keller, Bradley. From Small Molecules to Polymers: Linear and Nonlinear Optical Properties of Organic Conjugated Systems for Solar Applications.

Degree: PhD, Macromolecular Science & Engineering, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/144012

► The world is seeing rapid population growth and with this growth, energy demands have soared. Traditionally, fossil fuels have been used to meet these demands,… (more)

▼ The world is seeing rapid population growth and with this growth, energy demands have soared. Traditionally, fossil fuels have been used to meet these demands, but extraction of fossil fuels is detrimental to the environment, burning of fossil fuels contributes significantly to adding pollutants to the environment, and have directly resulted in climate change. This has spurred the public and scientists to search for energy sources that are more environmentally friendly and are renewable. The sun is the largest energy source in the solar system. If materials and devices can be designed to collect even a fraction of the sun’s energy, humanity’s energy needs will be me many times over. One of the most promising light harvesting materials is organic light harvesting materials because of their ease of processing, lightweight, high absorption capabilities, and flexibility. In this thesis, the optical properties of conjugated organic light harvesting materials were investigated. In order to improve the efficiency of these devices, the fundamental optical properties need to be understood. In the first study, the optical properties of light harvesting donor-acceptor polymers with the same donor monomer with different strength acceptors were investigated. Stronger acceptors donor-acceptor polymers had enhanced charge transfer characteristics, lower quantum yields, and shorter fluorescence lifetimes compared to weaker acceptor polymers. In the second study, the effect of donor conjugation length on the optical properties of donor-acceptor light harvesting polymers was investigated with ultrafast spectroscopic techniques. Polymers with longer donor conjugation lengths had higher extinction coefficients, higher charge transfer characteristics, and transient absorption experiments revealed additional species in the excited state. Computations studies related the electronic structures to the optical properties of the investigated polymers. Two new experiments were designed and installed for unprecedented wavelength selection and unprecedented long timescale investigations. An overview of a new nanosecond system that I have installed and two-photon absorption experiment that I have designed is presented. The experimental procedure and design is described. Preliminary results are presented demonstrating the success of this new system and experimental design. A new nanosecond transient experiment was installed. The experimental procedure for the nanosecond transient experiment is described. Preliminary results are presented demonstrating the successful implementation and operation of this new system. Advisors/Committee Members: Goodson III, Theodore G (committee member), Kim, Jinsang (committee member), Zgid, Dominika Kamila (committee member), Zimmerman, Paul (committee member).

Subjects/Keywords: Photophysical Investigation of Donor-Acceptor Light Harvesting Polymers; Engineering (General); Materials Science and Engineering; Chemistry; Science (General); Engineering; Science

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Keller, B. (2018). From Small Molecules to Polymers: Linear and Nonlinear Optical Properties of Organic Conjugated Systems for Solar Applications. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/144012

Chicago Manual of Style (16^th Edition):

Keller, Bradley. “From Small Molecules to Polymers: Linear and Nonlinear Optical Properties of Organic Conjugated Systems for Solar Applications.” 2018. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/144012.

MLA Handbook (7^th Edition):

Keller, Bradley. “From Small Molecules to Polymers: Linear and Nonlinear Optical Properties of Organic Conjugated Systems for Solar Applications.” 2018. Web. 12 Apr 2021.

Vancouver:

Keller B. From Small Molecules to Polymers: Linear and Nonlinear Optical Properties of Organic Conjugated Systems for Solar Applications. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/144012.

Council of Science Editors:

Keller B. From Small Molecules to Polymers: Linear and Nonlinear Optical Properties of Organic Conjugated Systems for Solar Applications. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/144012

University of Michigan

22. Copic, Davor. Fabrication of Polymer and Nanocomposite Microstructures and Microactuators by Capillary Infiltration and Replica Molding.

Degree: PhD, Mechanical Engineering, 2013, University of Michigan

URL: http://hdl.handle.net/2027.42/102390

► Addition of micro- and/or nanoscale textures to surfaces can enable engineering of a wide range of properties. Passive surfaces (using fixed microstructures) can manipulate cell… (more)

▼ Addition of micro- and/or nanoscale textures to surfaces can enable engineering of a wide range of properties. Passive surfaces (using fixed microstructures) can manipulate cell adhesion, liquid drag, and thermal and electrical contact resistance. Active surfaces (using shape-changing microstructures) can enable modulation of liquid wetting, adhesion, and optical properties. Nevertheless, it remains a challenge to fabricate the mechanically and environmentally robust microstructures and microactuators in large arrays. This thesis presents new fabrication methods for microstructured polymer and nanocomposite surfaces. Two approaches are pursued: capillary driven infiltration of fabricated carbon nanotube (CNT) microstructures and replica molding (REM) of master templates in liquid crystal networks (LCNs). First, it is demonstrated that CNT-polymer microstructures can function as robust large-area master molds. The fabricated microstructures include pins, tubes, re-entrant microwells, bent pillars, and high-aspect-ratio honeycombs (thickness of 400nm, aspect ratio 50:1). All are used as master structures for replica molding. A 25-fold replication sequence is shown with no physical degradation of the master or the replicas. Further, the increased stiffness and toughness of CNT-SU-8 microstructures is quantified. Second, active surfaces were created by capillary infiltration of paraffin into CNT forests. Large stroke sheet actuators, exhibiting up to 20% thermal strain at 175°C are shown. Third, thermally and optically active LCN microstructure replicas were created. Their generated strains were measured to be 6% and 0.25%, respectively. In situ monitoring of the LCN phase and order was also performed. Although having low strains, optically active microstructures are attractive for future work because they can be actuated individually and remotely. These scalable methods of fabricating microstructured surfaces, both with robust mechanical properties and active geometries, indicate promise for enhancement of liquid wetting, adhesion, optical properties, and thermal conductivity of surfaces and interfaces. However, further increases in the thermally and optically generated strains are needed to make useful active surfaces. This could be accomplished by either material reformulation, improvements in material processing, or strain amplification via design of microstructure geometry. Advisors/Committee Members: Hart, A. John (committee member), Kim, Jinsang (committee member), Kurabayashi, Katsuo (committee member), White, Timothy J. (committee member).

Subjects/Keywords: CNT-polymer Composite; Liquid Crystal Network; Microactuator; Active Surfaces; Mechanical Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Copic, D. (2013). Fabrication of Polymer and Nanocomposite Microstructures and Microactuators by Capillary Infiltration and Replica Molding. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/102390

Chicago Manual of Style (16^th Edition):

Copic, Davor. “Fabrication of Polymer and Nanocomposite Microstructures and Microactuators by Capillary Infiltration and Replica Molding.” 2013. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/102390.

MLA Handbook (7^th Edition):

Copic, Davor. “Fabrication of Polymer and Nanocomposite Microstructures and Microactuators by Capillary Infiltration and Replica Molding.” 2013. Web. 12 Apr 2021.

Vancouver:

Copic D. Fabrication of Polymer and Nanocomposite Microstructures and Microactuators by Capillary Infiltration and Replica Molding. [Internet] [Doctoral dissertation]. University of Michigan; 2013. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/102390.

Council of Science Editors:

Copic D. Fabrication of Polymer and Nanocomposite Microstructures and Microactuators by Capillary Infiltration and Replica Molding. [Doctoral Dissertation]. University of Michigan; 2013. Available from: http://hdl.handle.net/2027.42/102390

University of Michigan

23. Vartanian, Garen V. A Physiological and Psychometric Evaluation of Human Subconscious Visual Response and Its Application in Health Promoting Lighting.

Degree: PhD, Macromolecular Science and Engineering, 2016, University of Michigan

URL: http://hdl.handle.net/2027.42/133226

► Subconscious vision is a recent focus of the vision science community, brought on by the discovery of a previously unknown photoreceptor in the retina dedicated… (more)

▼ Subconscious vision is a recent focus of the vision science community, brought on by the discovery of a previously unknown photoreceptor in the retina dedicated to driving non-image-forming responses, intrinsically photosensitive retinal ganglion cells (ipRGCs). In addition to accepting inputs from rod and cone photoreceptors, ipRGCs contain their own photopigment, melanopsin, and are considered true photoreceptors. ipRGCs drive various non-image-forming photoresponses, including circadian photoentrainment, melatonin suppression, and pupil constriction. In order to understand more about ipRGC function in humans, we studied its sensitivity to light stimuli in the evening and day. First, we measured the sensitivity threshold of melatonin suppression at night. Using a protocol that enhances data precision, we have found the threshold for human melatonin suppression to be two orders of magnitude lower than previously reported. This finding has far-reaching implications since there is mounting evidence that nocturnal activation of the circadian system can be harmful. Paradoxically, ipRGCs are understimulated during the day. Optimizing daytime non-image-forming photostimulation has health benefits, such as increased alertness, faster reaction times, better sleep quality, and treatment of depression. In order to enhance ipRGC excitation, we aimed to circumvent adaptation (i.e. desensitization) of the photoresponse by using flickering instead of steady light. We find that properly timed flickering light enhances pupillary light reflex significantly when compared to steady light with 9-fold more energy density. Employing our findings, a new form of LED light is proposed to enhance subconscious visual responses at a typical indoor illuminance level. Using the silent substitution technique, a melanopsin-selective flicker is introduced into the light. A linear optimization algorithm is used to maximize the contrast of the subconscious, melanopsin-based response function while keeping conscious, cone-driven responses to the pulsing light fixed. Additional boundary conditions utilizing test color samples as an environmental mimic are introduced to limit the amount of perceived color change in a simulated environment. Two examples of lights are given to illustrate potential applications for general illumination and therapeutic purposes. For the lighting and electronics industry, we hope our study of subconscious-stimulative thresholds at night will better inform their design guidelines for health conscious products. Advisors/Committee Members: Wong, Kwoon Yiu (committee member), Ku, Pei-Cheng (committee member), Kim, Jinsang (committee member), Guo, L Jay (committee member).

Subjects/Keywords: vision science; psychometric physics; psychophysics; lighting engineering; depression; Biomedical Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Vartanian, G. V. (2016). A Physiological and Psychometric Evaluation of Human Subconscious Visual Response and Its Application in Health Promoting Lighting. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/133226

Chicago Manual of Style (16^th Edition):

Vartanian, Garen V. “A Physiological and Psychometric Evaluation of Human Subconscious Visual Response and Its Application in Health Promoting Lighting.” 2016. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/133226.

MLA Handbook (7^th Edition):

Vartanian, Garen V. “A Physiological and Psychometric Evaluation of Human Subconscious Visual Response and Its Application in Health Promoting Lighting.” 2016. Web. 12 Apr 2021.

Vancouver:

Vartanian GV. A Physiological and Psychometric Evaluation of Human Subconscious Visual Response and Its Application in Health Promoting Lighting. [Internet] [Doctoral dissertation]. University of Michigan; 2016. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/133226.

Council of Science Editors:

Vartanian GV. A Physiological and Psychometric Evaluation of Human Subconscious Visual Response and Its Application in Health Promoting Lighting. [Doctoral Dissertation]. University of Michigan; 2016. Available from: http://hdl.handle.net/2027.42/133226

University of Michigan

24. Kumar, Ramya. Directing Interfacial Events Using Biomimetic Polymer Brushes.

Degree: PhD, Chemical Engineering, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/144127

► Polymer brushes are versatile surface modification tools, wherein composition, architecture and biological functionality can be controlled precisely and independently. By growing biomimetic polymer chains from… (more)

▼ Polymer brushes are versatile surface modification tools, wherein composition, architecture and biological functionality can be controlled precisely and independently. By growing biomimetic polymer chains from substrate-bound initiator sites through atom transfer radical polymerization (ATRP), engineered biointerfaces were developed for four application areas. Spatioselective deactivation of ATRP initiator coatings made via chemical vapor deposition polymerization was demonstrated to synthesize micropatterned polymer brushes in a substrate-independent, modular and facile manner. Exposure of 2-bromoisobutyryl groups to UV light resulted in the loss of the bromine atom and effectively inhibited polymer brush growth. Microstructured brushes were selectively grown from those areas on the initiator that were protected from UV exposure, as confirmed by atomic force microscopy (AFM), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and imaging ellipsometry. Protein patterns based on specific as well as non-specific adsorption can be created on technologically relevant substrates such as polystyrene, PDMS, polyvinyl chloride and steel. Model surfaces can aid in examining different hypotheses relevant to viral adsorption and formulating design rules for virus-resistant coatings. Thermodynamic models predicted that the extent of viral adsorption is shaped by the interplay between electrostatic attraction offered by binding sites and steric and hydration repulsions arising from surrounding polymer brushes. To verify these predictions, electrostatically heterogeneous carbohydrate-functional brushes were developed. Experimental results confirmed model predictions and offered guidelines for designing virus-resistant surfaces in realistic scenarios where electrostatically attractive defects are prevalent. By allowing the carbohydrate brushes to attain brush thicknesses between 3-5 nm, low levels of protein and viral adsorption could be achieved, even when the defect density was as high as 25-30%. The development of polymeric materials that facilitate the culture of large numbers of human pluripotent stem cells in fully defined conditions, poses a critical engineering challenge. Prior work had indicated that modifying the extent of zwitterionic self-association of PMEDSAH coatings could enhance the propagation rate of human embryonic stem cells (hESCs). Moderately self-associated PMEDSAH coatings were reported to be capable of expanding an initial population of 20,000 hESCS to 4.7 billion pluripotent cells at the end of five weeks, which is 2-fold and 12-fold higher than the estimated propagation rates for unassociated and highly associated coatings respectively. It was hypothesized that a property-prediction tool based on statistical design of experiments could identify reaction parameters that would yield targeted gel architectures. Model predictions were used to decrease the critical thickness at which the wettability transition occurs by merely increasing the catalyst quantity from 1 mol% to 3 mol%. … Advisors/Committee Members: Lahann, Joerg (committee member), Krebsbach, Paul H (committee member), Kim, Jinsang (committee member), Scott, Timothy (committee member).

Subjects/Keywords: Polymer brushes; biomedical coatings; zwitterionic polymer brushes; statistical modeling; glycopolymers; virus-resistant coatings; Chemical Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kumar, R. (2018). Directing Interfacial Events Using Biomimetic Polymer Brushes. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/144127

Chicago Manual of Style (16^th Edition):

Kumar, Ramya. “Directing Interfacial Events Using Biomimetic Polymer Brushes.” 2018. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/144127.

MLA Handbook (7^th Edition):

Kumar, Ramya. “Directing Interfacial Events Using Biomimetic Polymer Brushes.” 2018. Web. 12 Apr 2021.

Vancouver:

Kumar R. Directing Interfacial Events Using Biomimetic Polymer Brushes. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/144127.

Council of Science Editors:

Kumar R. Directing Interfacial Events Using Biomimetic Polymer Brushes. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/144127

University of Michigan

25. Sulaiman, Santy. Synthesis and Characterization of Polyfunctional Polyhedral Silsesquioxane Cages.

Degree: PhD, Macromolecular Science & Engineering, 2011, University of Michigan

URL: http://hdl.handle.net/2027.42/89822

► Recent studies on octameric polyhedral silsesquioxanes, (RSiO1.5)8, indicate that the silsesquioxane cage is not just a passive component but appears to be involved in electron… (more)

▼ Recent studies on octameric polyhedral silsesquioxanes, (RSiO1.5)8, indicate that the silsesquioxane cage is not just a passive component but appears to be involved in electron delocalization with conjugated organic tethers in the excited state. This dissertation presents the synthesis and characterization of (RSiO1.5)8 molecules with unique photo-physical properties that provide support for the existence of conjugation that involves the (RSiO1.5)8 cage. The dissertation first discusses the elaboration of octavinylsilsesquioxane via cross-metathesis to form styrenyl-functionalized octasilsesquioxane molecules. Subsequent Heck coupling reactions of p-bromostyrenyl derivative provides vinylstilbene-functionalized octasilsesquioxane. The amino derivative, NH2VinylStilbeneOS, show highly red-shifted emission spectrum (100 nm from the simple organic analog p-vinylstilbene) and high two-photon absorption (TPA) cross-section value (100 GM/moiety), indicating charge-transfer processes involving the silsesquioxane cage as the electron acceptor. The unique photophysical properties of polyfunctional luminescent cubic silsesquiox-anes synthesized from ortho-8-, (2,5)-16-, and 24-brominated octaphenylsilsesquioxane (OPS) via Heck coupling show how the steric interactions of the organic tethers at the silsesquioxane cage corner affect conjugation with the silsesquioxane cage. Furthermore, the high TPA cross-section (10 GM/moiety) and photoluminescence quantum yield (20%) of OPS functionalized with 24 acetoxystyrenyl groups suggest that the existence excited states in these molecules with similar energies and decay rates: normal radiative p-p* transition and charge transfer involving the silsesquioxane cage. The fluoride ion-catalyzed rearrangement reactions of cage and polymeric silses-quioxanes provide a convenient route to a mixture of deca- and dodecameric silsesquioxane molecules in high yields, giving us the opportunity to investigate the effect of silsesquioxane cage geometry on their photophysical properties. The ability to recycle polymeric silsesquioxane resins, byproducts from cubic silsesquioxane syntheses, into useful cage silsesquioxane molecules adds another advantage. Lastly, we present the synthesis of octa(aminophenyl)silsesquioxane-based epoxy resins with coefficient of thermal expansion (CTE) as low as 25 °C/ppm without ceramic fillers. The CTEs of these resins can be tailored over an order of magnitude by choosing epoxy crosslinking agents having different flexibilities. Advisors/Committee Members: Laine, Richard M. (committee member), Banaszak Holl, Mark M. (committee member), Kim, Jinsang (committee member), Rasmussen, Paul G. (committee member).

Subjects/Keywords: Silsesquioxane; Hybrid Materials; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sulaiman, S. (2011). Synthesis and Characterization of Polyfunctional Polyhedral Silsesquioxane Cages. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/89822

Chicago Manual of Style (16^th Edition):

Sulaiman, Santy. “Synthesis and Characterization of Polyfunctional Polyhedral Silsesquioxane Cages.” 2011. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/89822.

MLA Handbook (7^th Edition):

Sulaiman, Santy. “Synthesis and Characterization of Polyfunctional Polyhedral Silsesquioxane Cages.” 2011. Web. 12 Apr 2021.

Vancouver:

Sulaiman S. Synthesis and Characterization of Polyfunctional Polyhedral Silsesquioxane Cages. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/89822.

Council of Science Editors:

Sulaiman S. Synthesis and Characterization of Polyfunctional Polyhedral Silsesquioxane Cages. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/89822

University of Michigan

26. Yang, Da Seul. Semiconducting Polymer Design and Interface Engineering for Efficient Charge Transport.

Degree: PhD, Macromolecular Science & Engineering, 2020, University of Michigan

URL: http://hdl.handle.net/2027.42/155202

► A major challenge to achieve macroscopic conjugated polymer (CP) alignment leading to efficient charge transport stems from the intrinsic disordered and entangled nature of CP… (more)

▼ A major challenge to achieve macroscopic conjugated polymer (CP) alignment leading to efficient charge transport stems from the intrinsic disordered and entangled nature of CP chains. Liquid crystalline (LC) CP design principles for directed alignment and their application to build a better understanding of charge transport in plastic electronics are discussed in this dissertation. First, molecular design parameters affecting the CP alignment are thoroughly investigated. The identified parameters, correlating with alignment characteristics via LC properties, are (a) the planarity of polymer chains; (b) intramolecular interaction moieties for induced chain planarity; (c) the effective bulkiness of side chains; and (d) surface energy of CPs. Second, cleavable side chains were introduced to the LC CPs as another design factor to achieve solvent-resistant highly aligned polymer films. The alignment behavior of the resulting new LC CP was examined in detail by adopting the floating film transfer method (FTM). In this method, an optimum amount of a high boiling point solvent was found to be vital to provide enough time for CPs to align. A high mobility anisotropy of ~14 was obtained through well-aligned CPs under the optimized condition. The subsequent side chain removal led to the formation of solvent-resistant highly aligned CP films. Overall, the outcomes provide insights into the realization of anisotropic properties of CPs in the solid thin films and offer an opportunity to enable a wide range of applications in organic electronics. FTM was employed as an interface engineering tool to investigate the charge transport of CPs in organic field effect transistors (OFETs). Although the transistor performance has been known to be critically affected by the polymer film-dielectric interface, it has been very difficult to isolate the contribution of CP alignment near the interface from that of the bulk film to the device performance. FTM has the capability of modulating CP alignment directions discretely in multilayered films, providing an opportunity to solve the daunting task. The resulting CP films prepared by FTM consisted of a bottom layer close to the polymer-dielectric interface and a top layer in contact with the source-drain electrodes. When the bottom layer had a parallel CP orientation and the CPs in the top layer were oriented perpendicular to the source-drain direction, the average hole mobility was larger by a factor of 3.3 than that of the opposite case. Moreover, OFET devices with combinations of the various bottom and top layer CP orientation directions revealed that the CP orientation direction of the bottom layer governed the overall device performance with a much smaller contribution from that of the top layer. These findings support that the CP alignment near the polymer-dielectric interface is a decisive factor for the charge transport in OFETs. Possible device performance enhancement through interface engineering is also demonstrated by investigating how the work function of electrodes can be modulated.… Advisors/Committee Members: Kim, Jinsang (committee member), Guo, L Jay (committee member), McNeil, Anne Jennifer (committee member), Pipe, Kevin Patrick (committee member).

Subjects/Keywords: organic electronics; conjugated polymers; polymer chain alignment; interface engineering; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Yang, D. S. (2020). Semiconducting Polymer Design and Interface Engineering for Efficient Charge Transport. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/155202

Chicago Manual of Style (16^th Edition):

Yang, Da Seul. “Semiconducting Polymer Design and Interface Engineering for Efficient Charge Transport.” 2020. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/155202.

MLA Handbook (7^th Edition):

Yang, Da Seul. “Semiconducting Polymer Design and Interface Engineering for Efficient Charge Transport.” 2020. Web. 12 Apr 2021.

Vancouver:

Yang DS. Semiconducting Polymer Design and Interface Engineering for Efficient Charge Transport. [Internet] [Doctoral dissertation]. University of Michigan; 2020. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/155202.

Council of Science Editors:

Yang DS. Semiconducting Polymer Design and Interface Engineering for Efficient Charge Transport. [Doctoral Dissertation]. University of Michigan; 2020. Available from: http://hdl.handle.net/2027.42/155202

University of Michigan

27. Kim, Ji Young. Asymmetry of Inorganic Nanostructures.

Degree: PhD, Materials Science and Engineering, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/147489

► Matured syntheses of inorganic nanocolloids today have allowed production of diverse asymmertic nanoparticles (NP) and even more complex assemblies, introducing a variety of nanomaterials with… (more)

▼ Matured syntheses of inorganic nanocolloids today have allowed production of diverse asymmertic nanoparticles (NP) and even more complex assemblies, introducing a variety of nanomaterials with unique properties. In many cases, the symmetry of the nanomaterials plays the crucial role in determining the electronic structure, optical activity and physical dynamics of the system. However, precise symmetry assignment to nanoscale materials is a challenging task due to their multicomponent nature and multiscale dynamics. Here we explore asymmetry of inorganic nanomaterials to discover fundamental mechanisms and dynamics of previously puzzling properties and develop a new methodology for syntheses and characterization. An example of overlooked asymmetry in nanoscale system was demonstrated with gold nanorod (Au NRs). Direct observations of electrostatic properties of Au NRs via off-axis electron holography and Kelvin force microscopy showed that Au NRs have distinct asymmetry of surface charge density and therefore, behave as non-centrosymmetric structures due to uneven distribution of cetyltrimethylammonium (CTA) moieties capping two ends of NRs. The electrostatic asymmetry of Au NRs and potentially other metallic nanostructures emerging from this study showed a new pathway to explain previously puzzling discrepancies in nonlinear optical (NLO) properties in seemingly centro-symmetric nanostructures. By taking the multicomponent nature of nano-colloids, especially originated from surface ligands, into consideration, we also showed that chiroptically active nanomaterials can be produced by self-assembled processes that are sensitive to subtle anisotropies and ligand-imposed surface of NPs. L-cysteine (L-Cys)– or D-cysteine (D-Cys)–stabilized NPs yields various chiral mesoscale structures including helices and angled conformation of nanoleaves, exhibiting unique chiropitcal properties by combining structural character with their material properties. More interestingly, the handedness of these structures depended solely on the specific Cys enantiomer, thus showing homochiral ensembles. The organic shell can introduce a property-governing asymmetry into nanoscale system, allowing better understanding relationships between geometrical parameters and properties of complex nanomaterials. The experimental and theoretical findings here can be generalized to other nanoscale materials carrying surface stabilizers and opens new possibilities for solution processed metamaterial devices. Advisors/Committee Members: Kotov, Nicholas (committee member), Norris, Theodore B (committee member), Kim, Jinsang (committee member), Mansfield, John F (committee member).

Subjects/Keywords: Inorganic nanomaterials; Asymmetry; Chirality; Electrostatic; Nonlinear optics; Self-assembly; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kim, J. Y. (2018). Asymmetry of Inorganic Nanostructures. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/147489

Chicago Manual of Style (16^th Edition):

Kim, Ji Young. “Asymmetry of Inorganic Nanostructures.” 2018. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/147489.

MLA Handbook (7^th Edition):

Kim, Ji Young. “Asymmetry of Inorganic Nanostructures.” 2018. Web. 12 Apr 2021.

Vancouver:

Kim JY. Asymmetry of Inorganic Nanostructures. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/147489.

Council of Science Editors:

Kim JY. Asymmetry of Inorganic Nanostructures. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/147489

University of Michigan

28. Wu, Jinghang. Morphology of Poly (3,4-Ethylene Dioxythiophene) (PEDOT) Thin Films, Crystals, Cubic Phases, Fibers and Tubes.

Degree: PhD, Macromolecular Science & Engineering, 2011, University of Michigan

URL: http://hdl.handle.net/2027.42/86361

► Poly(3,4-ethylene dioxythiophene) (PEDOT) is a chemically stable, conjugated polymer that is of considerable interest for a variety of organic electronic devices including microfabricated neural electrodes… (more)

▼ Poly(3,4-ethylene dioxythiophene) (PEDOT) is a chemically stable, conjugated polymer that is of considerable interest for a variety of organic electronic devices including microfabricated neural electrodes that interface with living cortical tissue. The properties of conducting polymers are strongly dependent on the morphology and structure of the material in the solid-state. The rigid π-π conjugated conformation of PEDOT facilitates charge transport and favors crystallization that reduces solubility and processability, making detailed studies of PEDOT morphology difficult. This has also made it hard to control the microstructure at a variety of length scales. In this dissertation the morphology of PEDOT has been studied and controlled at several different length scales from nanometers to micrometers. On the nanoscale, the primary intermolecular (100) d-spacing in PEDOT crystals has been controlled from 1.15 nm to 1.52 nm by using different counter-ions as dopants. The surface morphology and crystallinity of electrochemically deposited PEDOT films have been controlled by changing deposition conditions. A highly ordered, crystalline PEDOT-Br phase was formed during electrochemical deposition in the presence of bromine counterions. On the tens of nanometers scale, isotropic PEDOT bicontinuous cubic structures with extremely large surface areas were developed using ternary non-ionic surfactant, water and oil systems. On the micrometer scale, aligned PEDOT fibers and tubes were prepared by electrospinning blends of poly(lactide-co-glycolide) (PLGA) or poly(caprolactone) (PCL) and EDOT monomer onto a rotating wheel or a dielectric gap in a metal substrate. These aligned fibers and tubes were shown to precisely direct neural regeneration in specific directions in vitro. These developments help understand the structure and properties of conjugated polymers for use in organic electronic devices. Advisors/Committee Members: Kim, Jinsang (committee member), Martin, David C. (committee member), Green, Peter F. (committee member), Lahann, Joerg (committee member).

Subjects/Keywords: Conductive Polymer PEDOT Morphology; Conductive Polymer Cubic Structure; PEDOT Crystals; Conductive Polymer Fibers and Tubes; Materials Science and Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wu, J. (2011). Morphology of Poly (3,4-Ethylene Dioxythiophene) (PEDOT) Thin Films, Crystals, Cubic Phases, Fibers and Tubes. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/86361

Chicago Manual of Style (16^th Edition):

Wu, Jinghang. “Morphology of Poly (3,4-Ethylene Dioxythiophene) (PEDOT) Thin Films, Crystals, Cubic Phases, Fibers and Tubes.” 2011. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/86361.

MLA Handbook (7^th Edition):

Wu, Jinghang. “Morphology of Poly (3,4-Ethylene Dioxythiophene) (PEDOT) Thin Films, Crystals, Cubic Phases, Fibers and Tubes.” 2011. Web. 12 Apr 2021.

Vancouver:

Wu J. Morphology of Poly (3,4-Ethylene Dioxythiophene) (PEDOT) Thin Films, Crystals, Cubic Phases, Fibers and Tubes. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/86361.

Council of Science Editors:

Wu J. Morphology of Poly (3,4-Ethylene Dioxythiophene) (PEDOT) Thin Films, Crystals, Cubic Phases, Fibers and Tubes. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/86361

29. Furgal, Joseph C. Synthesis and Structure-Photophysical Property Relationships of T8, T10, T12 and Oligomeric Organic Functionalized Silsesquioxanes.

Degree: PhD, Chemistry, 2015, University of Michigan

URL: http://hdl.handle.net/2027.42/111393

► Silsesquioxanes with conjugated organic tethers (chromophores) offer high orders of functionality (> 8 tethers), unusual enhanced absorption, emission and charge separation over free chromophores, excited… (more)

▼ Silsesquioxanes with conjugated organic tethers (chromophores) offer high orders of functionality (> 8 tethers), unusual enhanced absorption, emission and charge separation over free chromophores, excited state electron delocalization, and high thermal stability. This dissertation presents the synthesis and characterization of organic functionalized T10 and T12 [RSiO1.5]10,12 molecules, with emphasis on their synthesis by fluoride catalyzed rearrangement from [RSiO1.5]n and an understanding of their unique photophysical properties targeting components in optoelectronic devices. Initial discussion focuses on the synthesis of silsesquioxanes from silica via conversion of rice hull ash (RHA) silica to spirosiloxanes [i.e. Si(2-methyl-2,4-pentane-diolato)2] by reaction with 2-Me-2,4-pentanediol and catalytic NaOH. The resulting spirosiloxane reacts with selected arylLi reagents to form mono-aryl-spirosiloxane, suggesting a pentacoordinate silicon based mechanism. These aryl-spirosiloxanes are then converted through fluoride catalysis to novel aryl-silsesquioxanes [RSiO1.5]8,10,12. Thereafter we detail the development of [RSiO1.5]10,12 materials by fluoride catalyzed rearrangement and its mechanisms. F – catalyzed rearrangement of polymeric and octameric SQs is indispensable to the synthesis of [RSiO1.5]10/12, and mixed [R1R2SiO1.5]10,12 molecules in up to 95% yield. [PhSiO1.5]10 is synthesized in the highest reported yield to date (~50%), and is used as a model system for mechanism studies. The likely mechanistic paths taken to form T10 and T12 SQs are analyzed by experiment with MALDI/NMR to identify intermediates and computational modeling for the most likely pathways. The most favorable pathway to T10 from T8 involves coincidental participation of fluoride and water with a net enthalpy of ~-24 kcal/mol. We also explore in detail the photophysical properties of [StilbenevinylSiO1.5]8,10,12, which show similar absorption and emission in solution, but decreasing fluorescence quantum efficiencies with increasing cage size, suggesting more chromophore interactions and non-radiative decay. [StilbenevinylSiO1.5]10 shows the highest two-photon absorption cross-section of this series (5.7 GM/chromophore), offering the best polarization and charge transfer character. Fluorescence upconversion fluorescence lifetime studies on [StilbenevinylSiO1.5]8,10,12 find ultrafast charge transfer dynamics (<1 ps) indicative of chromophore-chromophore interactions in the excited state, unobserved for stilbenvinylSi(OEt)3, suggesting excited state charge delocalization. Advisors/Committee Members: Laine, Richard M. (committee member), Goodson Iii, Theodore G. (committee member), Kim, Jinsang (committee member), Bartlett, Bart (committee member), Sanford, Melanie (committee member).

Subjects/Keywords: Silsesquioxanes; Photophysical Properties; Fluoride Rearrangement; Organosilicon Chemistry; Energy; Chemistry; Science

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Furgal, J. C. (2015). Synthesis and Structure-Photophysical Property Relationships of T8, T10, T12 and Oligomeric Organic Functionalized Silsesquioxanes. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/111393

Chicago Manual of Style (16^th Edition):

Furgal, Joseph C. “Synthesis and Structure-Photophysical Property Relationships of T8, T10, T12 and Oligomeric Organic Functionalized Silsesquioxanes.” 2015. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/111393.

MLA Handbook (7^th Edition):

Furgal, Joseph C. “Synthesis and Structure-Photophysical Property Relationships of T8, T10, T12 and Oligomeric Organic Functionalized Silsesquioxanes.” 2015. Web. 12 Apr 2021.

Vancouver:

Furgal JC. Synthesis and Structure-Photophysical Property Relationships of T8, T10, T12 and Oligomeric Organic Functionalized Silsesquioxanes. [Internet] [Doctoral dissertation]. University of Michigan; 2015. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/111393.

Council of Science Editors:

Furgal JC. Synthesis and Structure-Photophysical Property Relationships of T8, T10, T12 and Oligomeric Organic Functionalized Silsesquioxanes. [Doctoral Dissertation]. University of Michigan; 2015. Available from: http://hdl.handle.net/2027.42/111393

University of Michigan

30. Kim, Hyunsoo. Organic Photodiodes and Their Optoelectronic Applications.

Degree: PhD, Electrical & Computer Eng PhD, 2017, University of Michigan

URL: http://hdl.handle.net/2027.42/137168

► Recently, organic photodiodes (OPDs) have been acknowledged as a next-generation device for photovoltaic and image sensor applications due to their advantages of large area process,… (more)

▼ Recently, organic photodiodes (OPDs) have been acknowledged as a next-generation device for photovoltaic and image sensor applications due to their advantages of large area process, light weight, mechanical flexibility, and excellent photoresponse. This dissertation targets for the development and understanding of high performance organic photodiodes for their medical and industrial applications for the next-generation. As the first research focus, A dielectric / metal / dielectric (DMD) transparent electrode is proposed for the top-illumination OPDs. The fabricated DMD transparent electrode showed the maximum optical transmittance of 85.7 % with sheet resistance of 6.2 ohm/sq. In the second part of the thesis, a development of novel transfer process which enables the dark current suppression for the inverted OPD devices will be discussed. Through the effort, we demonstrated OPD with high D* of 4.82 x 10¹² Jones at reverse bias of 1.5 V with dark current density (Jdark) of 7.7 nA/cm2 and external quantum efficiency (EQE) of 60 %. Additionally in the third part, we investigate a high performance low-bandgap polymer OPD with broadband spectrum. By utilizing the novel transfer process to introduce charge blocking layers, significant suppression of the dark current is achieved while high EQE of the device is preserved. A low Jdark of 5 nA/cm2 at reverse bias of 0.5 V was achieved resulting in the highest D* of 1.5 x 10¹³ Jones. To investigate the benefit for the various OPD applications, we developed a novel 3D printing technique to fabricate OPD on hemispherical concave substrate. The techniques allowed the direct patterning of the OPD devices on hemispherical substrates without excessive strain or deformation. Lastly, a simulation of the OPD stacked a-ITZO TFT active pixel sensor (APS) pixel with external transimpedance amplifier (TIA) readout circuit was performed. Advisors/Committee Members: Kanicki, Jerzy (committee member), Kim, Jinsang (committee member), Guo, L Jay (committee member), Phillips, Jamie Dean (committee member).

Subjects/Keywords: Organic Photodiode; Electrical Engineering; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kim, H. (2017). Organic Photodiodes and Their Optoelectronic Applications. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/137168

Chicago Manual of Style (16^th Edition):

Kim, Hyunsoo. “Organic Photodiodes and Their Optoelectronic Applications.” 2017. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/137168.

MLA Handbook (7^th Edition):

Kim, Hyunsoo. “Organic Photodiodes and Their Optoelectronic Applications.” 2017. Web. 12 Apr 2021.

Vancouver:

Kim H. Organic Photodiodes and Their Optoelectronic Applications. [Internet] [Doctoral dissertation]. University of Michigan; 2017. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/137168.

Council of Science Editors:

Kim H. Organic Photodiodes and Their Optoelectronic Applications. [Doctoral Dissertation]. University of Michigan; 2017. Available from: http://hdl.handle.net/2027.42/137168

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations