EAPSI: Environmental Testing of Multi-Crystalline Thin Film Solar Cells

Nietzold Tara, Tempe AZ

Investigators

Abstract

There exist solar cell materials that have higher efficiencies than the current market technology made from silicon. The reason these are not the standard technology is because they are exceedingly expensive to create. Many of the materials displaying high efficiencies are grown through very slow and high-purity techniques that are expensive and energy intensive. This project will therefore work to create and measure cost-effective III-V solar cells for their performance and behavior in normal operating conditions such as: different humidity levels, high and low temperatures, and varying light exposure. The research will be done in collaboration with Dr. Martial Ducamp, an expert in in-situ transmission electron microscopy (TEM), at Nanyang Technological University in Singapore, Singapore. The results of the study will identify possible causes of lower efficiencies in low-cost III-V solar cells, which will in turn make it possible to improve the manufacturing procedures used to produce lower cost, higher efficiency solar cells. The relationship between material properties and electrical performance will be tested using transmission electron microscopy (TEM) coupled with electron beam induced current (EBIC). TEM observes inter-atomic interactions and bonds, while, simultaneously, EBIC measures localized carrier collection throughout the sample. By correlating the TEM images with EBIC signal, certain structures, arrangements or bonds can be identified as resulting in good or bad performance. The project will also evaluate TEM/EBIC correlations under device operating conditions to identify weakly performing regions and potential causes that arise due to real, environmental factors. With a greater understanding of the causes of these low-performing regions, it will be possible to iterate making improvements to the III-V growth process until devices can be manufactured that are optimized both for cost and efficiency. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the National Research Foundation of Singapore.