Improved interfacial properties of electrodeposited Cu2ZnSn(S,Se)4 thin‐film solar cells by a facile post‐heat treatment process

Abstract Cu2ZnSn(S,Se)4 (CZTSSe) thin‐film solar cells offer various advantages including excellent optical and electrical properties, nontoxic and earth‐abundant raw materials, and a simple fabrication process. However, these devices suffer from a high deficit of the open‐circuit voltage (VOC), mainly caused by interface recombination, which increases with increasing surface roughness. In this study, to achieve a high VOC and enhance the overall device performance, an additional heat treatment process was introduced during the fabrication of co‐electrodeposited rough CZTSSe solar cells, and its effect on the photovoltaic properties was systematically investigated using various characterization techniques including diode analysis, transient photovoltage decay measurement, evaluation of the temperature dependency of the open‐circuit voltage, current–voltage and drive‐level capacitance pro…