Cu2ZnSn(S, Se)4 (CZTSSe) is one of most competitive photovoltaic materials for its earth-abundant reserves, environmental friendliness, and high stability.The quality of CZTSSe absorber determines the power-conversion efficiency (PCE) of CZTSSe solar cells. The absorber's quality lies on post-selenization process, which is the reaction of Cu-Zn-Sn precursor and selenium vapor. And the post-selenization is dependent on various factors (e.g. temperature, precursor composition, reaction atmosphere, etc).However, synergistic regulation of these factors cannot be realized under a widely-used single-temperature zone selenization condition.Here, in our dual-temperature zone selenization scheme, a solid-liquid and solid-gas (solid precursor and liquid/gas phase Se) synergistic reaction strategy has been developed to precisely regulate the selenization. Pre-deposited excess liquid Se provides high Se chemical potential to drive a direct and fast formation of the CZTSSe phase, significantly reducing the amount of binary and ternary compounds within phase evolution. And organics removal can be accomplished via a synergistic optimization of Se condensation and subsequent volatilization. We achieve a high-performance CZTSSe solar cell with a remarkable PCE of 13.6%, and the highest large-area PCE of 12.0% (over 1cm2). Our strategy will provide a new idea for further improving efficiency of CZTSSe solar cells via phase evolution regulation, and also for other complicated multi-compound synthesis.
@article{arxiv.2303.02368,
title = {Controlling selenization equilibrium enables high-quality Cu2ZnSn(S, Se)4 absorbers for efficient solar cells},
author = {Xiao Xu and Jiazheng Zhou and Kang Yin and Jinlin Wang and Licheng Lou and Menghan Jiao and Bowen Zhang and Dongmei Li and Jiangjian Shi and Huijue Wu and Yanhong Luo and Qingbo Meng},
journal= {arXiv preprint arXiv:2303.02368},
year = {2024}
}