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You searched for subject:(High detectivity). Showing records 1 – 2 of 2 total matches.

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Georgia Tech

1. Khan, Talha Mansur. Organic semiconductor bulk heterojunction diodes with low dark current for photovoltaic, photodetection, and scintillator-free ionizing radiation detection applications.

Degree: PhD, Electrical and Computer Engineering, 2016, Georgia Tech

Solid-state organic semiconductor-based photovoltaics (OPV) are an emerging technology being developed to generate clean and sustainable electricity in light weight, flexible and shatter-proof form factors. In this dissertation, firstly, a method to enhance the environmental stability of OPV is developed. Previous work has shown that the physical adsorption of the polymer polyethylenimine on the surface of conductors results in a significant reduction of the conductor work function. In this work, it is demonstrated that the reduction in work function of the conductors using polyethylenimine is independent of the order of deposition and can also be achieved by depositing the conductors on top of polyethylenimine. Consequently, novel OPV architectures are developed in which the commonly used but particularly air unstable calcium electrode is replaced by polyethylenimine in conjunction with various air stable metals as top electron-collecting electrodes. The performance of the novel calcium-free OPV is found to be comparable to reference OPV containing calcium electrodes. Secondly, it is experimentally demonstrated that the energy of the charge-transfer complex formed by molecular interactions between the donor and acceptor components of the photoactive layer in OPV is the energy gap relevant for the thermal generation of carriers that leads to the reverse saturation current. Organic photodetectors that define the state-of-the-art in terms of dark current density (JDark on the order of 6 pA/cm2) and specific detectivity (D* > 1014 Jones at visible wavelengths) are demonstrated by employing a donor-acceptor pair with a large charge-transfer complex energy, in conjunction with devices with large shunt resistance. The approach to reproducibly fabricate high shunt resistance devices is detailed, which includes the optimization of the photoactive layer morphology, the photoactive layer thickness, and the work function of the charge collecting-electrodes. A proof of concept for scintillator-free organic semiconductor detectors of ionizing radiation enabled by this approach is also demonstrated. Advisors/Committee Members: Kippelen, Bernard (advisor), Milor, Linda (committee member), Graham, Samuel (committee member), Naeemi, Azad (committee member), Frazier, Albert B. (committee member).

Subjects/Keywords: Organic solar cells; Organic photodetectors; High detectivity

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

APA (6th Edition):

Khan, T. M. (2016). Organic semiconductor bulk heterojunction diodes with low dark current for photovoltaic, photodetection, and scintillator-free ionizing radiation detection applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58182

Chicago Manual of Style (16th Edition):

Khan, Talha Mansur. “Organic semiconductor bulk heterojunction diodes with low dark current for photovoltaic, photodetection, and scintillator-free ionizing radiation detection applications.” 2016. Doctoral Dissertation, Georgia Tech. Accessed June 25, 2019. http://hdl.handle.net/1853/58182.

MLA Handbook (7th Edition):

Khan, Talha Mansur. “Organic semiconductor bulk heterojunction diodes with low dark current for photovoltaic, photodetection, and scintillator-free ionizing radiation detection applications.” 2016. Web. 25 Jun 2019.

Vancouver:

Khan TM. Organic semiconductor bulk heterojunction diodes with low dark current for photovoltaic, photodetection, and scintillator-free ionizing radiation detection applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2019 Jun 25]. Available from: http://hdl.handle.net/1853/58182.

Council of Science Editors:

Khan TM. Organic semiconductor bulk heterojunction diodes with low dark current for photovoltaic, photodetection, and scintillator-free ionizing radiation detection applications. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/58182

2. Liu, Xilan. Polymer Photodetectors: Device Structure, Interlayer and Physics.

Degree: PhD, Polymer Engineering, 2013, University of Akron

Photodetectors are light responsive devices that convert optical signals into electric signals. Photodetectors have wide applications in image sensing, environmental monitoring, day- and night-surveillance, chemical and biological detection, industrial process control, communication, planetary probing and so on. Currently, photodetectors based on GaN, ZnO, Si, InGaAs and bulk PbS cover different sub-bands from UV to infrared region. These photodetectors are expensive and some of them require to be operated at low temperature, which certainly limits their applications. Polymer photodetectors made with conjugated polymers possess the unique features, including room-temperature operation, high sensitivity, low working voltage, low cost, thin profile, large area and flexibility. Ultrasensitive polymer photodetectors with high response speed and spectral response ranging from UV to near infrared have been demonstrated. However, new device structure, high responsivity and stable polymer photodetectors needs to be developed. In my dissertation, we reported various methods to enhance the performance of polymer photodetectors. By solvent annealing and post-production thermal annealing, we were able to demonstrate that polymer photodetectors possess comparable responsivity to inorganic counterparts. We have, for the first time, developed the inverted device structure for polymer photodetectors. By utilizing inorganic nanowires and quantum dots as either cathode or anode buffer layer, we were able to demonstrate robust polymer photodetectors. We also investigate the device performance versus energy offset between the workfunction of anode electrode and the valance band of conjugated polymers, band offset at the heterojunction and purity of conjugated polymers. Advisors/Committee Members: Karim, Alamgir (Committee Chair), Gong, Xiong (Advisor).

Subjects/Keywords: Polymers; Materials Science; Electrical Engineering; polymer photovoltaics; polymer photodetectors; bulk heterojunction; high responsivity; detectivity; inverted device structure; interfacial layers; ZnO nanowire; CdTe quantum dot; device physics

…energy level alignment for high detectivity infrared polymer PDs. viii ACKNOWLEDGEMENTS A… …with high detectivity and fast response to various spectra range have been reported.11,35,43… …x28;PTZBTTT-BDT) whose bandgap is as narrow as 1.1 eV and demonstrated high detectivity… …morphology control and ohmic contact for high performance infrared polymer PDs. In summary, BHJ… …Interests .27 III. SOLUTION-PROCESSED POLYMER PHOTODETECTORS WITH HIGH EXTERNAL QUANTUM… 

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

APA (6th Edition):

Liu, X. (2013). Polymer Photodetectors: Device Structure, Interlayer and Physics. (Doctoral Dissertation). University of Akron. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=akron1384334220

Chicago Manual of Style (16th Edition):

Liu, Xilan. “Polymer Photodetectors: Device Structure, Interlayer and Physics.” 2013. Doctoral Dissertation, University of Akron. Accessed June 25, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1384334220.

MLA Handbook (7th Edition):

Liu, Xilan. “Polymer Photodetectors: Device Structure, Interlayer and Physics.” 2013. Web. 25 Jun 2019.

Vancouver:

Liu X. Polymer Photodetectors: Device Structure, Interlayer and Physics. [Internet] [Doctoral dissertation]. University of Akron; 2013. [cited 2019 Jun 25]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=akron1384334220.

Council of Science Editors:

Liu X. Polymer Photodetectors: Device Structure, Interlayer and Physics. [Doctoral Dissertation]. University of Akron; 2013. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=akron1384334220

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