The present investigation mainly addresses the open circuit voltage (Voc) issue in kesterite based Cu₂ZnSn(S,Se)₄ solar cells by simply introducing alkali metal fluoride nanolayers (~ several nm NaF, or LiF) to lower the work functions of the front ITO contacts without conventional hole-blocking ZnO layers. Kelvin probe measurements confirmed that the work function of the front ITO decreases from 4.82 to 3.39 and 3.65 eV for NaF and LiF, respectively, resulting in beneficial band alignment for electron collection and/or hole blocking on top electrodes. Moreover, a 10.4% power conversion efficiency (~ 11.5% in the cell effective area) CZTSSe cell with improved Voc of up to 90 mV has been attained. This demonstration may provide a new direction of further boosting the performance of copper chalcogenide based solar cells as well.

目前的研究主要解决了基于钾长石的Cu ₂ ZnSn（S，Se）₄的开路电压（Voc）问题太阳能电池可通过简单地引入碱金属氟化物纳米层（约数纳米NaF或LiF）来降低前ITO触点的功函数，而无需常规的空穴阻挡ZnO层。开尔文探针测量结果证实，对于NaF和LiF，前ITO的功函分别从4.82降至3.39 eV和3.65 eV，从而为电子收集和/或顶部电极上的空穴阻挡带来了有利的能带对准。此外，已经实现了具有高达90 mV的改进Voc的10.4％功率转换效率（在电池有效面积中约为11.5％）的CZTSSe电池。该演示还可以提供进一步提高基于硫属硫化物的太阳能电池性能的新方向。