Band Tail Engineering in Kesterite Cu2ZnSn(S,Se)4 Thin-Film Solar Cells with 11.8% Efficiency

• DOI: 10.1021/acs.jpclett.8b01433
• Publication Date: 2018-07-26T16:06:56Z
• Authors: Myeng Gil Gang; Seung Wook Shin; Mahesh P. Suryawa...; Uma V. Ghorpade; Zhaoning Song; Jun Sung Jang; Jae Ho Yun; Hyeonsik Cheong; Yanfa Yan; Jin Hyeok Kim
• Keywords: Kesterite; Quantum Efficiency

Herein, we report a facile process, i.e., controlling the initial chamber pressure during postdeposition annealing, to effectively lower band tail states in synthesized CZTSSe thin films. Through detailed analysis of external quantum efficiency derivative ( dEQE/ dλ) and low-temperature photoluminescence (LTPL) data, find that are significantly influenced by annealing pressure. After carefully optimizing deposition processes device design, able synthesize kesterite films with energy differences between inflection d(EQE)/dλ LTPL as small 10 meV. These enable fabrication solar cells champion 11.8% low Voc deficit 582 mV. The results suggest process is an effective approach reduce