SPLTRAK Abstract Submission
Revealing Sub-Cell Degradation of Multi-Junction Solar Cells by Absolute Electroluminescence Imaging
Youyang Wang1, Liying Li2, Xiaobo Hu1, Yun Jia1, Guoen Weng1, Xianjia Luo1, Shaoqiang Chen1,4, Hidefumi Akiyama3
1Department of Electronic Engineering, East China Normal University, Shanghai, China
/2Department of Computer Science and Technology, East China Normal University, Shanghai, China
/3Institute for Solid State Physics, The University of Tokyo, Chiba, Japan
/4Ministry of Education Nanophotonics & Advanced Instrument Engineering Research Center, East China Normal University, Shanghai, China

Photovoltaic solar cells degrade or even fail during long-term storage, affecting their conversion efficiency and lifetime. In this work, an industry-standard InGaP/GaAs/InGaAs multi-junction solar cell (MJSC) was monitored in a non-working idle state for more than two years. The sub-cell degradation caused by prolonged storage and its origin have been revealed by using the absolute electroluminescence (EL) imaging technique. Several potential defects were found to gradually exacerbate over time, introducing more non-radiative recombination centers and reducing the sub-cell external radiative efficiency under low-injection conditions. Quantitative evaluation results show that long-term idle resulted in an over 0.2% efficiency degradation and an over 1% fill factor degradation for each sub-cell, which is mainly originated from the non-radiative recombination loss.