We present a copper indium gallium selenide (CIGS) solar cell with improved performance, numerically simulated using LUMERICAL FDTD and DEVICE Multiphysics simulation software and considering the charge transportation, ambient temperature, buffer layer thickness, and defect density for detailed analysis. One of the significant concerns of the existing CIGS solar cells is the presence of the toxic cadmium sulfide (CdS) buffer layer and higher buffer/absorber layer interface dominant recombination. Replacing CdS with zinc sulfide (ZnS) is a propitious way to address such issues and enhance the CIGS solar cell’s performance while achieving efficiencies similar to that of the CIGS solar cell with CdS as the buffer layer. Furthermore, the performance is improved by employing a transparent conductive oxide of fluorine-doped tin oxide (FTO) and zinc tin oxide (ZTO) window layer for better charge flow and low-current losses. However, the real solar cell operating conditions are entirely different from the predefined standard conditions. To get a more detailed analysis, we demonstrate the impact of variations of operating temperature, ZnS buffer layer thickness, defect density on the short-circuit current, open-circuit voltage, and overall performance of the solar cell. We found that the simulated efficiency of the proposed CIGS solar cell (FTO–ZTO/ZnS/CIGS/Mo) with ZnS and FTO–ZTO layer is 29.6% with a short-circuit current of 49.3 mA / cm2, higher than that of the CIGS solar cell (Al:ZnO/CdS/CIGS/Mo) with CdS that was achieved in our previous work. Thus the study can help to develop a more promising, efficient, and cost-effective CIGS solar cell.

中文翻译：

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高效铜铟镓硒太阳能电池的设计与性能研究

我们展示了一种性能改进的铜铟镓硒 (CIGS) 太阳能电池，使用 LUMERICAL FDTD 和 DEVICE Multiphysics 仿真软件进行数值模拟，并考虑电荷传输、环境温度、缓冲层厚度和缺陷密度进行详细分析。现有 CIGS 太阳能电池的重要问题之一是存在有毒的硫化镉 (CdS) 缓冲层和更高的缓冲/吸收层界面主要复合。用硫化锌 (ZnS) 代替 CdS 是解决此类问题和提高 CIGS 太阳能电池性能的有利方法，同时实现与以 CdS 作为缓冲层的 CIGS 太阳能电池的效率相似的效率。此外，通过采用掺氟氧化锡 (FTO) 和氧化锌锡 (ZTO) 窗口层的透明导电氧化物提高了性能，以实现更好的电荷流动和低电流损耗。然而，实际的太阳能电池工作条件与预定义的标准条件完全不同。为了获得更详细的分析，我们展示了工作温度、ZnS 缓冲层厚度、缺陷密度对短路电流、开路电压和太阳能电池整体性能的影响。我们发现所提出的具有 ZnS 和 FTO-ZTO 层的 CIGS 太阳能电池（FTO-ZTO/ZnS/CIGS/Mo）的模拟效率为 29.6%，短路电流为 49.3 mA / cm2，高于CIGS 太阳能电池 (Al:ZnO/CdS/CIGS/Mo) 与我们之前的工作中实现的 CdS。