Multi-junction Solar Cells of Lead (II) Selenide Quantum Dots and Zinc Oxide Nanowires

Abstract

Solar energy is a greener alternative to coal or natural gas derived energy, but the inherently low efficiencies of current commercial silicon solar cells prevent it from being a viable competitor in the energy industry. Using semiconductor nanocrystals, also known as quantum dots, can increase the efficiency of solar cells; the band gaps of these particles can be adjusted by changing the sizes of these particles, allowing them to be tuned to optimally absorb sunlight. Incorporating nanowires have also shown to increase efficiency in thin film solar cells, as the comb-like structure allows for more efficient collection of charge carriers. This project involves the fabrication and study of the efficiency of solar cells with a heterojunction zinc oxide (ZnO) nanowires and lead (II) selenide (PbSe) quantum dots. The goal of this project is to use layers of differently sized PbSe quantum dots to make multijunction solar cells, which could further increase efficiencies.