The Effect of Cadmium, Calcium and Zinc on Optoelectronic Properties of PbS Quantum Dots

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Mirfasih, Mohammad Hassan | 2014

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 46061 (07)
University: Sharif University of Technology
Department: Materials Science and Engineering
Advisor(s): Simchi, Abdolreza
Abstract:
In recent years, much attention has been focused on quantum dot films due to their high amount of surface area and their size-dependant band-gap tenability. However, high surface area results in increase in energy traps in case of insufficient surface passivation. In this research, PbS colloidal quantum dots were synthesized via hot injection route having the size of 3 nm approximately. Then cationic doping with Zn, Ca and Cd and ligand exchange of long oleic acid with short organic mercaptopionic acid were done. Excitonic peak of these dots and photoluminescence peak appeard in wavelengths of 930 and 1100 nm respectively. Optimum film thickness was also determined as 300 nm. Quantum dot solar cells with two structures of Schottky and bulk heterojunction were fabricated and doping effect on solar cell performance was inversigated. Based on the results and due to doping, open-circuit voltage was enhanced from 0.4 to 0.6 volts approximately and 2.46% was achieved as the highest power conversion efficiency of the solar cell
Keywords:
Quantum Dot ; Lead Sulfide ; Doping ; Solar Cells ; Ligand Exchange

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