Dissertations, Theses, and Capstone Projects

Date of Degree

2-2014

Document Type

Dissertation

Degree Name

Ph.D.

Program

Engineering

Advisor

ROBERT R. ALFANO

Subject Categories

Electrical and Electronics

Keywords

Efficiency, Photovoltaic, Quantum dots, Quantum efficiency, Solar cells, Structures

Abstract

This thesis research focuses on developing a hybrid form of solar cell based on zinc(hydr)oxide and its composites with graphite oxide, TiO2, quantum dot, electrolyte and . This work expands upon the Gratzel solar cell with a dye in TiO2.

Due to various structural and optical characteristics, zinc(hydr)oxide (Zn(OH)2) and its porous composites with 2% and 5% graphite oxide(GO) can be used for various applications including the manufacture of various , protective elements in electric and electronic appliances, as gas-sensors, catalysts, in cosmetics a UV light absorber, and solar cells.

In this research, both TiO2 and zinc(hydr)oxide (refer as Zn(OH)2 ) and its porous composites with 2% and 5% graphite oxide(GO) (refer as ZnGO-2 and ZnGO-5 respectively) have been studied with photoactive quantum dots (QDs). The goal of this research was to understand the optical properties of Zn (OH)2, ZnGO-2 and ZnGO-5 (i.e. We determined the band gap of these three materials using absorptions, photoluminescence and photo-conductivity), structural characterizations of these three samples (i.e.We determined critical points transitions), time resolved fluorescence of these three materials, (i.e. We determined the lifetime of the carrier, the rise time of the carrier, relaxation, and carrier density using new model) and application in the Gratzel like quantum dots (QDs) sensitized hybrid Zn(OH)2/ZnGO solar cells compared with TiO2 which made with QD(CdSe and PbS ).The main objective of this thesis was to develop hybrid solar cell with Zn(OH)/ZnGO material and TiO2 to make alternative designs for the fabrication of quantum dots sensitized Zn(OH)/ZnGO hybrid solar cells that can enhance the efficiencies as well as reduce the cost by making it more amenable to large scale production.

In hybrid solar cells, the role of the conductive glass substrate with the performance of Zn(OH)2/ZnGO/QD(CdSe and/or PbS) /Electrolyte or Perovskite based photovoltaic devices, as well as fabricate new photovoltaic devices, to improve the efficiencies in power. The focus of this doctoral thesis was to introduce new composite material such as Zn(OH)2 with QDs CdSe(visible), PbS(UV and NIR) for their applications in new solar cells which incorporate energy transfer processes in order to improve light harvesting.The basic idea to obtain maximum energy efficiency is to absorb most of the solar spectrum in the 3 zones: UV, visible and NIR light. The photoexcitation and processes involved with carriers excitons and multiexcition generations in uv.

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