Investigation and Fabrication of Silicon Thin-Film Tandem Solar cell

Abstract

In the dissertation we approached the higher efficiency and reliable thin film tandem silicon solar cell with amorphous intrinsic layer tuning process For silicon thin-film solar cell it is well known that one of the most important methods for preparing amorphous silicon doped with hydrogen (a-Si:H) with good stability against light soaking degradation is by properly tuning H2 dilution ratio in the intrinsic i-layer However it is hard to improve the longevity of Gen 5 silicon thin-film tandem module by manipulating the H2 ratio within one i-layer alone because hydrogen treatment could easily compromise the front P-layer by PECVD To solve this problem we propose the “graded i-layer” method which incorporates multiple i-layers with different of hydrogen dilution ratios in place of the original single i-layer By this method the solar cell could provide higher initial power and the degradation ratio of the module could be reduced by approximately 2% comparing to the module with single i-layer However it has been observed that increasing hydrogen dilution has the undesirable effect of slowing down the deposition rate of the intrinsic layer which reduce the efficiency of production To counter this problem we have designed a systematic approach to enhance the utilization rate of the feedstock gas Silane By our method consumption of feedstock gas can be reduced by more than 40% and deposition rate of the intrinsic layer can be increased by 30% compared to the method of only increasing the hydrogen dilution without sacrificing module performance and stability For see through module we found adding hardener into the conventional see-through tandem modules that the efficiency degraded only by 6 0% for the see-through tandem modules with hardener after 6 IEC cycles

Date of Award	2016 Feb 15
Original language	English
Supervisor	Shoou-Jinn Chang (Supervisor)