Monolithic two-terminal (2T) perovskite/CuInSe₂ (CIS) tandem solar cells (TSCs) combine the promise of an efficient tandem photovoltaic (PV) technology with the simplicity of an all-thin-film device architecture that is compatible with flexible and lightweight PV. In this work, we present the first-ever 2T perovskite/CIS TSC with a power conversion efficiency (PCE) approaching 25% (23.5% certified, area 0.5 cm²). The relatively planar surface profile and narrow band gap (∼1.03 eV) of our CIS bottom cell allow us to exploit the optoelectronic properties and photostability of a low-Br-containing perovskite top cell as revealed by advanced characterization techniques. Current matching was attained by proper tuning of the thickness and bandgap of the perovskite, along with the optimization of an antireflective coating for improved light in-coupling. Our study sets the baseline for fabricating efficient perovskite/CIS TSCs, paving the way for future developments that might push the efficiencies to over 30%.

中文翻译：

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效率接近 25% 的单片两端子钙钛矿/CIS 串联太阳能电池

单片双端 (2T) 钙钛矿/CuInSe ₂ (CIS) 串联太阳能电池 (TSC) 结合了高效串联光伏 (PV) 技术的前景和全薄膜器件架构的简单性，该架构兼容柔性和轻量级光伏。在这项工作中，我们展示了首个 2T 钙钛矿/CIS TSC，其功率转换效率 (PCE) 接近 25%（23.5% 认证，面积 0.5 cm ²）。我们的 CIS 底部电池相对平坦的表面轮廓和窄带隙（~1.03 eV）使我们能够利用先进的表征技术所揭示的低溴钙钛矿顶部电池的光电特性和光稳定性。电流匹配是通过适当调整钙钛矿的厚度和带隙以及优化抗反射涂层以改善光耦合来实现的。我们的研究为制造高效钙钛矿/独联体 TSC 奠定了基础，为未来可能将效率提高到 30% 以上的发展铺平了道路。