Wide bandgap perovskite solar cells (PSCs) have attracted significant attention because they can be applied to the top cells of tandem solar cells. However, high open-circuit voltage () deficit (>0.4 V) result from poor crystallization and high non-radiative recombination losses become a serious limitation in the pursuit of high performance. Here, the relevance between different PbI proportions and performance parameters are revealed through analysis of surface morphology, residual stress, and photostability. The increase of PbI proportion promotes crystal growth and reduces the work function of the perovskite film surface and promotes the energy level alignment with the carrier transport layer, which decreased the deficit. However, residual PbI exacerbated the stress level of perovskite film, and the resulting lattice disorder deteriorated the photostability of the device. Ultimately, after the synergistic passivation of residual PbI and PEAI, the achieves 1.266 V and deficit is less than 0.4 V, the record value in wide bandgap PSCs.

中文翻译：

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高性能宽带隙钙钛矿太阳能电池，VOC 赤字低于 0.4 V

宽禁带钙钛矿太阳能电池（PSC）因其可应用于叠层太阳能电池的顶部电池而引起了极大的关注。然而，结晶不良导致的高开路电压（>0.4 V）和高非辐射复合损耗成为追求高性能的严重限制。在这里，通过对表面形貌、残余应力和光稳定性的分析揭示了不同 PbI 比例和性能参数之间的相关性。 PbI比例的增加促进了晶体生长，降低了钙钛矿薄膜表面的功函数，促进了与载流子传输层的能级对准，从而减少了缺陷。然而，残留的PbI加剧了钙钛矿薄膜的应力水平，由此产生的晶格无序恶化了器件的光稳定性。最终，残余PbI和PEAI协同钝化后，电压达到1.266 V，赤字小于0.4 V，这是宽带隙PSC的记录值。