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You searched for +publisher:"University of Texas – Austin" +contributor:("Milliron, Delia (Delia Jane)"). Showing records 1 – 2 of 2 total matches.

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University of Texas – Austin

1. Staller, Corey Michael. Electron transport in doped semiconductor nanocrystals.

Degree: PhD, Chemical Engineering, 2019, University of Texas – Austin

Electron transport through semiconductor nanocrystal (NC) systems is almost entirely understood by analogs to bulk science. The physics governing electron transport within NCs is entirely analogous to bulk semiconductors with extreme spatial constraints. In contrast, the physics of electrons conducting between NCs is understood through the physics of amorphous materials, granular metals, or bulk semiconductors, depending on the structure of the NC ensemble. Herein is an investigation of how dopant distribution engineering can be utilized to modulate near surface depletion in NC films. The dependence of NC film conductivity on dopant distribution is eliminated by surface passivation. A code to fit the optical absorption of colloidal NCs is developed to account for surface scattering, depletion, size heterogeneity, and dopant heterogeneity. This code is used to define the conduction within an individual NC. The intra-NC conduction is used as a metric to describe and define the phase diagram of NC film electron transport. Using the criteria developed here, we make metallic films in a controlled manner. This work illustrates an overview of bulk electron transport and an introduction of NC film electron transport in Chapter 1. These descriptions will then be used to investigate the powerful capability to engineer intra-NC dopant distribution to manipulate NC film conductivity in Chapter 2. The intra-NC conductance is then investigated using a novel code to fit the optical absorption of NCs in Chapter 3. With a deep understanding of intra-NC transport, the electron transport phase diagram is constructed in Chapter 4. Advisors/Committee Members: Milliron, Delia (Delia Jane) (advisor), Akinwande, Deji (committee member), Korgel, Brian (committee member), Mullins, Charles B (committee member).

Subjects/Keywords: Conduction; Nanocrystals; Tin-doped indium oxide; Depletion; Metal-insulator transition

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APA (6th Edition):

Staller, C. M. (2019). Electron transport in doped semiconductor nanocrystals. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/1487

Chicago Manual of Style (16th Edition):

Staller, Corey Michael. “Electron transport in doped semiconductor nanocrystals.” 2019. Doctoral Dissertation, University of Texas – Austin. Accessed August 08, 2020. http://dx.doi.org/10.26153/tsw/1487.

MLA Handbook (7th Edition):

Staller, Corey Michael. “Electron transport in doped semiconductor nanocrystals.” 2019. Web. 08 Aug 2020.

Vancouver:

Staller CM. Electron transport in doped semiconductor nanocrystals. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2019. [cited 2020 Aug 08]. Available from: http://dx.doi.org/10.26153/tsw/1487.

Council of Science Editors:

Staller CM. Electron transport in doped semiconductor nanocrystals. [Doctoral Dissertation]. University of Texas – Austin; 2019. Available from: http://dx.doi.org/10.26153/tsw/1487

2. Heo, Sungyeon. Doped tungsten oxide nanocrystals for next generation electrochromic windows.

Degree: PhD, Chemical Engineering, 2019, University of Texas – Austin

Doped tungsten oxide (WO₃ [subscript -x]) nanocrystals (NCs) have lots of potential for next generation electrochromic windows compared to bulk thin films. The difference lies in intrinsic WO₃ [subscript -x] NC properties of shape and crystalline anisotropy with localized surface plasmon resonance absorption in the shorter wavelength near-infrared range, which can directly affect the major electrochromic performance of switching speed, optical modulation, and cycling stability. This work illustrates how doped WO₃ [subscript -x] NC properties are effectively utilized for enhancing the electrochromic performance. First, how shape anisotropic properties can generate highly porous film is studied using different aspect ratio of WO₂.₇₂ nanorods. By changing the nanorod interaction to electrostatic repulsion from solution ligand-stripping chemistry, highly porous mesoporous thin film from randomly packed nanorods is fabricated. Incorporating guest inorganic materials of niobium polyoxometalate clusters followed by chemical condensation, dual-band modulation of electrochromic films on flexible substrates are demonstrated, tackling cycling stability, and optical modulation issues. Second, how doped semiconductor NCs are effectively used for dynamic Bragg stacks with targeted performance of ‘on and off’ reflectance is studied. Dynamic reflectance tuning can affect the color tuning as well as efficient heat blocking. Judicious NC selection of indium tin oxide and WO₃ [subscript -x] NCs from mechanistic understanding of electrochemical modulation of optical properties, optimization of film processing, and reliable refractive index data from in situ ellipsometry enable accurate Bragg stack optimization from simulation and experimental realization. Third, using monoclinic WO₂.₇₂ nanorods as a model system having different size of three intracrystalline tunnel sites, we study spectroelectrochemical properties with different cation system (lithium, sodium, and tetrabutylammonium ion). In doing so, Al₂O₃ atomic layer deposition is employed to prevent electrolytes degradation and allows to study spectroelectrochemical properties. Na⁺ electrolytes system gives higher coloration efficiency than Li⁺ electrolytes and mainly capacitive charging behavior owing to its occupancy in the hexagonal tunnel sites. The results of these studies suggest general approach to improve electrochromic performance where shape and crystalline anisotropic properties of doped metal oxide nanocrystals can be effectively utilized for impacting spectroelectrochemical properties. Advisors/Committee Members: Milliron, Delia (Delia Jane) (advisor), Korgel, Brian (committee member), Mullins, Charles (committee member), Bonnecaze, Roger (committee member), Crooks, Richard (committee member).

Subjects/Keywords: Tungsten oxide; Electrochromics; Nanocrystals

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

APA (6th Edition):

Heo, S. (2019). Doped tungsten oxide nanocrystals for next generation electrochromic windows. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/5875

Chicago Manual of Style (16th Edition):

Heo, Sungyeon. “Doped tungsten oxide nanocrystals for next generation electrochromic windows.” 2019. Doctoral Dissertation, University of Texas – Austin. Accessed August 08, 2020. http://dx.doi.org/10.26153/tsw/5875.

MLA Handbook (7th Edition):

Heo, Sungyeon. “Doped tungsten oxide nanocrystals for next generation electrochromic windows.” 2019. Web. 08 Aug 2020.

Vancouver:

Heo S. Doped tungsten oxide nanocrystals for next generation electrochromic windows. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2019. [cited 2020 Aug 08]. Available from: http://dx.doi.org/10.26153/tsw/5875.

Council of Science Editors:

Heo S. Doped tungsten oxide nanocrystals for next generation electrochromic windows. [Doctoral Dissertation]. University of Texas – Austin; 2019. Available from: http://dx.doi.org/10.26153/tsw/5875

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