Device Postannealing Enabling over 12% Efficient Solution‐Processed Cu2ZnSnS4 Solar Cells with Cd2+ Substitution

• DOI: 10.1002/adma.202000121
• Publication Date: 2020-07-02T05:46:38Z
• Authors: Zhenghua Su; Guangxing Liang; Ping Fan; Jingting Luo; Zhuanghao Zheng; Zhigao Xie; Wei Wang; Shuo Chen; Juguang Hu; Yadong Wei; Chang Yan; Jialiang Huang; Xiaojing Hao; Fangyang Liu
• Keywords: Kesterite; Open-circuit voltage; Cadmium sulfide; Indium tin oxide; Carrier lifetime

Abstract Kesterite Cu 2 ZnSnS 4 is a promising photovoltaic material containing low‐cost, earth‐abundant, and stable semiconductor elements. However, the highest power conversion efficiency of thin‐film solar cells based on only about 11% due to low open‐circuit voltage fill factor mainly caused by antisite defects unfavorable heterojunction interface. In this work, postannealing procedure proposed complete Cd‐alloyed device. The device significantly enhances performance indium tin oxide promotes moderate interdiffusion elements between layers in As result diffusion Cu, Zn, In, Sn, interfacial electron hole densities are improved, leading achievement suitable band alignment for carrier transport. also reduces interface traps deep‐level defects, contributing decreased nonradiative recombination. Therefore, both an over 12% pure sulfide‐based kesterite obtained.