Improving power conversion efficiency of photovoltaic devices has been widely investigated; however, most research studies mainly focus on the modification of the absorber layer. Here, we present an approach to enhance the efficiency of Cu(In,Ga)(S,Se)₂ (CIGSSe) thin-film solar cells simply by tuning the CdS buffer layer. The CdS buffer layer was deposited by chemical bath deposition. Indium doping was done during the growth process by adding InCl₃ into the growing aqueous solution. We show that the solar cell efficiency is increased by proper indium doping. Based on the characteristics of the single CdS (with or without In-doping) layer and of the CIGSSe/CdS interface, we conclude that the efficiency enhancement is attributed to the interface-defect passivation of heterojunction, which significantly improves both open circuit voltage and fill factor. The results were supported by SCAPS simulations, which suggest that our approach can also be applied to other buffer systems.

中文翻译：

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掺杂铟的CdS缓冲层提高Cu（In，Ga）（S，Se）₂太阳能电池的效率

提高光伏器件的功率转换效率已被广泛研究。但是，大多数研究主要集中在吸收层的改性上。在这里，我们提出一种仅通过调整CdS缓冲层即可提高Cu（In，Ga）（S，Se）₂（CIGSSe）薄膜太阳能电池效率的方法。通过化学浴沉积来沉积CdS缓冲层。在生长过程中通过添加InCl ₃进行铟掺杂到不断增长的水溶液中。我们表明通过适当的铟掺杂可以提高太阳能电池的效率。基于单层CdS（具有或不具有In-doping）层和CIGSSe / CdS接口的特性，我们得出结论，效率的提高归因于异质结的界面缺陷钝化，这大大改善了开路电压和填充因子。结果得到SCAPS仿真的支持，这表明我们的方法也可以应用于其他缓冲系统。