Wide bandgap (WB) organic–inorganic hybrid perovskites (OIHPs) with a bandgap ranging between 1.7 and 2.0 eV have shown great potential to improve the efficiency of single‐junction silicon or thin‐film solar cells by forming a tandem structure with one of these cells or with a narrow bandgap perovskite cell. However, WB‐OIHPs suffer from a large open‐circuit voltage (V_oc) deficit in photovoltaic devices, which is associated with the phase segregation of the materials under light illumination. In this work the photoinstability is demonstrated and V_oc loss can be addressed by combining grain crystallization and grain boundary passivation, achieved simultaneously through tuning of perovskite precursor composition. Using FA_0.17Cs_0.83PbI_3–xBr_x (x = 0.8, 1.2 1.5, and 1.8), with a varied bandgap from 1.72 to 1.93 eV, as the model system it is illustrated how precursor additive Pb(SCN)₂ should be matched with a proper ratio of FAX (I and Br) to realize large grains with defect‐healed grain boundaries. The optimized WB‐OIHPs show good photostability at both room‐temperature and elevated temperature. Moreover, the corresponding solar cells exhibit excellent photovoltaic performances with the champion V_oc/stabilized power output efficiency reaching 1.244 V/18.60%, 1.284 V/16.51%, 1.296 V/15.01%, and 1.312 V/14.35% for WB‐OIHPs with x = 0.8, 1.2, 1.5, and 1.8, respectively.

中文翻译：

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成分调整的宽带隙钙钛矿：从晶粒工程到稳定性和性能改善

带隙介于1.7和2.0 eV之间的宽带隙（WB）有机-无机杂化钙钛矿（OIHP）具有巨大的潜力，可通过与其中之一形成串联结构来提高单结硅或薄膜太阳能电池的效率细胞或具有窄带隙的钙钛矿细胞。但是，WB-OIHP在光伏设备中存在很大的开路电压（V _oc）缺陷，这与光照射下材料的相分离有关。在这项工作中，证明了光不稳定性，并且可以通过结合晶粒的结晶和晶界的钝化来解决V _oc的损失，这是通过调整钙钛矿前体组成同时实现的。使用FA _0.17 Cs_0.83 PbI _{3- x} Br _x（x = 0.8、1.2 1.5和1.8），带隙在1.72至1.93 eV之间变化，作为模型系统，它说明了前体添加剂Pb（SCN）₂应该如何与合适的相匹配FAX（I和Br）的比率可实现具有缺陷愈合的晶界的大晶粒。优化的WB-OIHP在室温和高温下均表现出良好的光稳定性。此外，相应的太阳能电池具有出色的光伏性能，具有WB-OIHP的冠军V _oc /稳定的功率输出效率分别达到1.244 V / 18.60％，1.284 V / 16.51％，1.296 V / 15.01％和1.312 V / 14.35％。x分别为0.8、1.2、1.5和1.8。