高效无机CsPbI2Br钙钛矿太阳能电池表面钝化的简便方法

近年来,基于CsPbI2Br的钙钛矿太阳能电池(PVSC)由于能在效率和稳定性之间获得良好平衡而受到越来越多的关注.通过溶液法制备的CsPbI2Br钙钛矿薄膜通常包含各种缺陷,为了获得具有高性能和良好稳定性的钙钛矿太阳能电池,这些缺陷需要被钝化.针对此问题,本文报道了一种简便的缺陷钝化策略,即通过在CsPbI2Br钙钛矿表面旋涂KF溶液来对其进行缺陷钝化.结果表明,沉积的KF大部分位于钙钛矿表面的晶界处,而钙钛矿膜的降解通常始于晶界,因此钝化后的PVSC具有更高的稳定性.稳态和时间分辨光致发光光谱均表明钙钛矿的缺陷被KF显著钝化了.最终,基于KF处理的CsPbI2Br的电池器件能量转换效率(PCE)提高到了15.01%,同时具有较大的开路电压(VOC,1.26 V).与之相比,基于CsPbI2Br的对照器件的PCE仅为14.14%,VOC只有1.18 V.

A facile surface passivation method for efficient inorganic CsPbI2Br perovskite solar cells with efficiencies over 15%

Recently,perovskite solar cells(PVSCs)based on CsPbI2Br have attracted increasing attention owing to their good balance between efficiency and stability.Solutionprocessed CsPbI2Br perovskites usually contain various defects which need passivation for PVSCs with high-performance as well as good stability.Since the degradation of perovskite films usually begins at the grain boundaries,here we report a facile defect passivation strategy by spin-coating a KF solution on the CsPbI2Br perovskite surface.The deposited KF salt mostly locates at the grain boundaries of the perovskite surface,resulting in PVSCs with improved stability.Both steady-state and time-resolved photoluminescence results suggest that the defects of perovskite were significantly passivated by KF treatment.Consequently,the best-performance PVSC based on CsPbI2Br with KF treatment shows an enhanced power conversion efficiency(PCE)of 15.01%with a larger open circuit voltage(VOC)of 1.26 V in comparison with the pristine CsPbI2Br-based counterpart which exhibits an inferior PCE of 14.14%with a VOC of 1.18 V.