Mixed-halide perovskite solar cells (PSCs) with wide band gap (WBG) have attracted increasingly intensive attention because they are ideally suited for tandem photovoltaics. However, the device performance and stability are still undesirable due to the existence of photoinduced phase segregation. Here, we precisely assembled a highly crystalline blocking structure onto the WBG perovskite plane via in situ epitaxial growth to address this issue. It was found that the blocking structure contributes to the release of lattice strain, the enhancement of the halide-ion migration barrier, and effective defect passivation of WBG perovskites. Consequently, an impressive open-circuit voltage of 1.25 V (maximum 1.26 V) with a champion efficiency of 21.80% (certified 21.52%) was obtained in a 1.65 eV mixed-halide PSC with outstanding photostability. The semitransparent device with a certified efficiency of 19.15% was overlaid on a silicon subcell to make a four-terminal tandem configuration, demonstrating a high efficiency of 28.83%.

具有宽带隙 (WBG) 的混合卤化物钙钛矿太阳能电池 (PSC) 引起了越来越多的关注，因为它们非常适合串联光伏发电。然而，由于存在光致相分离，器件性能和稳定性仍然不理想。在这里，我们通过原位将高度结晶的阻挡结构精确地组装到 WBG 钙钛矿平面上外延生长来解决这个问题。研究发现，阻挡结构有助于晶格应变的释放、卤化物离子迁移势垒的增强以及 WBG 钙钛矿的有效缺陷钝化。因此，在具有出色光稳定性的 1.65 eV 混合卤化物 PSC 中获得了令人印象深刻的 1.25 V（最大 1.26 V）开路电压和 21.80%（经认证为 21.52%）的冠军效率。将认证效率为 19.15% 的半透明器件叠加在硅子电池上，形成四端串联配置，展示出 28.83% 的高效率。