Physical Sciences and Mathematics Commons^™

Effects Of Disorder On Thermoelectric Properties Of Semiconducting Polymers, Zlatan Aksamija, Dhandapani Venkataraman, Connor J. Boyle, Meenakshi Upadhyaya

Zlatan Aksamija

High Photoresponse From Solution Processed Conventional And Inverted Ultraviolet Photodetectors, Görkem Memi̇şoğlu, Canan Varlikli

Turkish Journal of Electrical Engineering and Computer Sciences

The optical and electrical properties of conventional and inverted type ultraviolet photodetectors (UVPDs) with active layers of poly(9,9-dioctylfluorenyl-2,7-ylenethynylene (PFE), $N$,$N'$-bis-$n$-butyl-1,4,5,8-naphthalenediimide (BNDI), and zincoxide (ZnO) are introduced. Optimized devices showed high photoresponse, external quantum efficiency (EQE), and detectivity (D*) values. Under 365 nm 1 mW/cm$^{2}$, the conventional device (ITO/PEDOT:PSS/[(PFE:BNDI) (3:1):8 wt% ZnO]/Al) and the inverted device (ITO/[(PFE:BNDI)(3:1):8 wt% ZnO]/Au) gave photoresponsivities of 515 mA/W and 316 mA/W, D* of 1.12 $\times$ 10$^{14 }$Jones and 0.71 $\times$ 10$^{14 }$Jones, and EQE of 174% and 107%, respectively. Annealing the devices at polymer's glass transition temperature (T$_{g}$ 60 $^{\circ}$ C), enhanced these values to …

Nano And Nanostructured Materials For Optical Applications, Panit Chantharasupawong

Electronic Theses and Dissertations

Nano and nanostructured materials offer unique physical and chemical properties that differ considerably from their bulk counterparts. For decades, due to their fascinating properties, they have been extensively explored and found to be beneficial in numerous applications. These materials are key components in many cutting-edge optic and photonic technologies, including photovoltaics, waveguides and sensors. In this dissertation, the uses of nano and nanostructured materials for optical applications are investigated in the context of optical limiting, three dimensional displays, and optical sensing. Nanomaterials with nonlinear optical responses are promising candidates for self-activating optical limiters. In the first part of this study, …

Redefining The Operation And Design Considerations Of Organic Solar Cells: Role Of Morphology And Defect States, Biswajit Ray

Open Access Dissertations

Organic photovoltaic (OPV) technology is currently a topic of great interest for potentially low cost solar energy conversion and possibility of many novel PV applications (e.g., building-integrated PV, portable solar cells). Successful commercialization of this technology, however, will require significant improvement in efficiency and lifetime. In the last few years, innovation in novel polymer synthesis has raised the efficiency of OPV above 10%, at par with a-Si and earth-abundant solar cells. Further improvement in performance relies on breakthroughs in device design, which requires profound understanding of the physics of device operation. A major challenge in the design of the state …

Multipolymer Interactions In Bulk Heterojunction Photovoltaic Devices, Grant Olson

Physics

Multipolymer photovoltaics, single layer devices made up of multiple photoactive polymers, can create organic photovoltaics (OPVs) with a wider spectral response than single polymer systems without the difficult fabrication of a tandem. Our group has successfully created multipolymer solar devices with 2% power conversion efficiency. We have analyzed the optical and electrical properties of these devices, and found that it may be possible for polymers to assist each other with charge extraction, though combining polymers disrupts single polymer crystallinity.

Liquid Crystal Materials And Tunable Devices For Optical Communications, Fang Du

Electronic Theses and Dissertations

In this dissertation, liquid crystal materials and devices are investigated in meeting the challenges for photonics and communications applications. The first part deals with polymer-stabilized liquid crystal (PSLC) materials and devices. Three polymer-stabilized liquid crystal systems are developed for optical communications. The second part reports the experimental investigation of a novel liquid-crystal-infiltrated photonic crystal fiber (PCF) and explores its applications in fiber-optic communications. The curing temperature is found to have significant effects on the PSLC performance. The electro-optic properties of nematic polymer network liquid crystal (PNLC) at different curing temperatures are investigated experimentally. At high curing temperature, a high contrast, …