Cesium-based inorganic perovskite solar cells (PSCs), especially for the CsPbI₂Br-based solar cells, have attained extensive attention due to its excellent thermal and phase stability. Solution-prepared CsPbI₂Br films usually have some defects which demand to be passivated for PSCs and also their degradations often happen at the grain boundaries (GBs). Herein, by using polymethylmethacrylate (PMMA) solution, we optimize the perovskite film growth and further investigate the effect of PMMA treatment on the properties of the CsPbI₂Br films. Time-resolved photoluminescence (TRPL) displays that the PMMA coating can improve the photoluminescence lifetime of CsPbI₂Br perovskite films. Therefore, it is proved that PMMA coating film can effectively passivate the defects of the pure CsPbI₂Br films, suppress the charge recombination with increased electron extraction efficiency, which improves the performance of solar cells. Consequently, the devices based on CsPbI₂Br films with PMMA solution treatment exhibit average power conversion efficiency (PCE) over 11.18%, which is much higher than the efficiency of 9.69% for pure CsPbI₂Br-based solar cells.

铯基无机钙钛矿太阳能电池（PSC），尤其是基于CsPbI ₂ Br的太阳能电池，因其出色的热稳定性和相稳定性而受到广泛关注。溶液制备的CsPbI ₂ Br薄膜通常具有一些缺陷，需要对PSC进行钝化，而且它们的降解通常发生在晶界（GBs）处。在其中，通过使用聚甲基丙烯酸甲酯（PMMA）溶液，我们优化了钙钛矿膜的生长，并进一步研究了PMMA处理对CsPbI ₂ Br膜性能的影响。时间分辨光致发光（TRPL）表明，PMMA涂层可以改善CsPbI ₂的光致发光寿命钙钛矿薄膜。因此，证明了PMMA涂层膜可以有效地钝化纯CsPbI ₂ Br膜的缺陷，抑制电荷复合并提高电子提取效率，从而改善了太阳能电池的性能。因此，基于CsPbI ₂ Br薄膜并经过PMMA固溶处理的器件的平均功率转换效率（PCE）超过11.18％，远高于纯CsPbI ₂ Br基太阳能电池的9.69％的效率。