The development of mixed tin-lead (Sn-Pb)-based perovskite solar cells (PSCs) with low band gap (1.2–1.4 eV) has become critical not only for pushing single-junction devices toward the maximum efficiency given by the Shockley-Queisser limit, but also for enabling all-perovskite tandem devices beyond this limit. However, achieving high power-conversion efficiency (PCE) and long-term device operation stability simultaneously remains a significant challenge for Sn-Pb-based PSCs. Here, we demonstrate near ideal-band-gap (∼1.34 eV) methylammonium-free Sn-Pb-based PSCs with high efficiency (∼20%) and promising operational stability of maintaining >80% of initial PCE over 750 h under maximum-power-point tracking. The key to this success is the use of a SnCl₂⋅3FACl complex additive that improves the microstructure and reduces the development of residual stress in the Sn-Pb perovskite thin films, which in turn enhances the efficiency and stability of the Sn-Pb-based ideal-band-gap PSCs.

具有低带隙（1.2–1.4 eV）的混合锡铅（Sn-Pb）基钙钛矿太阳能电池（PSC）的开发已变得至关重要，这不仅是为了使单结器件朝着Shockley-Si提供的最大效率迈进。 Queisser限制，也可用于启用超出此限制的全钙钛矿串联设备。然而，对于基于Sn-Pb的PSC，同时实现高功率转换效率（PCE）和长期设备操作稳定性仍然是一项重大挑战。在这里，我们展示了接近理想带隙（〜1.34 eV）的无甲铵锡（Sn-Pb）PSC，具有高效率（〜20％），并有望在750 h内在最大功率下保持超过80％的初始PCE的操作稳定性。功率点跟踪。成功的关键是使用SnCl ₂⋅3FACl复合添加剂，可改善Sn-Pb钙钛矿薄膜的微观结构并减少残余应力的产生，进而提高Sn-Pb基理想带隙PSC的效率和稳定性。