Ag-Nanoseed-Mediated Deposition Kinetics and Crystallization Boosting toward Efficient Electrodeposited CZTSe Solar Cells on Transparent FTO Substrates
Zhiying Zhu, Ye Dai, Jingling Liu, Wei Wang, Zhicheng Lin, Xinsheng Liu, Jianping Chen, Zuliang Du, Ke ChengAbstract
Electrodeposited Cu2ZnSn(S,Se)4 (CZTSSe) on fluorine-doped tin oxide (FTO) is promising for transparent photovoltaic devices yet constrained by inhomogeneous nucleation, inferior crystallization, and severe back-contact barriers, limiting its efficiency to ∼4.7%. Herein, a Ag nanoseed layer is developed to synergistically regulate the electrodeposition kinetics and postselenization crystallization. The Ag nanoseeds afford abundant highly active heterogeneous nucleation sites to reduce Cu2+ migration barriers and yield dense uniform metallic precursors. Upon selenization, the generated low-melting Ag–Sn–Se liquid phase accelerates grain growth and suppresses deep-level defects. Meanwhile, Ag incorporation tailors interfacial energy-level alignment and converts the unfavorable Schottky hole barrier into a hole-transport-favorable interface. Owing to these combined effects, the optimized device achieves an impressively enhanced efficiency from 3.22% to 6.30%, setting a new efficiency record for FTO-based electrodeposited CZTSe devices. This work offers a facile route toward efficient, low-cost chalcogenide photovoltaics for transparent optoelectronics.