钙钛矿太阳能电池(PSCs)发展迅速, 其能量转换效率(PCE)被一再刷新, 但长期稳定性还有待提高。目前大部分高效率钙钛矿太阳能电池在惰性气体环境中完成制备, 成本高且操作空间有限, 不利于产业化应用。本研究成功在空气中制备了具有超长稳定性的混合阳离子钙钛矿太阳能电池, 系统探究了A位阳离子掺杂对钙钛矿微观结构、光电性能以及稳定性的影响。实验结果表明, 掺杂FA⁺和Cs⁺可以提高钙钛矿薄膜质量, 优化钙钛矿/SnO₂的能级排列, 抑制载流子复合, 显著提高器件的光电转换效率、长期以及湿热稳定性。Cs_0.05MA_0.35FA_0.6PbI₃电池的最佳PCE为19.34%, 在(20±5) ℃, 相对湿度<5%的黑暗环境中放置242 d后, 仍保持初始效率的85%。MAPbI₃电池在同样测试条件下放置112 d后, 效率下降为初始值的30%。掺杂FA⁺和Cs⁺也显著提高了电池的抗热和抗湿性。Cs_0.05MA_0.35FA_0.6PbI₃电池分别在(85±5) ℃、相对湿度20%~30%和(20±5) ℃、相对湿度80%~90%的黑暗环境中放置96 h后, PCE分别为初始值的99%和84%, 而MAPbI₃在同样条件下的PCE仅为初始值的70%和56%。本研究为在空气环境制备高效、超长稳定的混合阳离子钙钛矿太阳能电池提供了参考。

Perovskite solar cells (PSCs) are developing rapidly and their power conversion efficiency (PCE) has been repeatedly refreshed, but their long-term stability still needs to be improved. At present, most of the preparation of high-efficiency PSCs is completed in the inert gas, with high cost and limited operating space, which is not conducive to its industrial application. Here, perovskite solar cells with mixed cation, displaying ultra-long stability, were successfully prepared in the air. Effects of A-site cation doping on the microstructure, optoelectronic properties and stability of the perovskite were systematically investigated. The experimental results show that FA⁺ and Cs⁺ co-doping improves the quality of perovskite films, modulates the energy level arrangement of perovskite/SnO₂, suppresses carrier complexation, and significantly improves the PCE, long-term, wet and thermal stability of the cell. The optimal PCE of Cs_0.05MA_0.35FA_0.6PbI₃ cells is 19.34%, maintaining 85% of the initial efficiency after reserving for 242 d in dark environment at (20±5) ℃ and <5% relative humidity. In contrast, the PCE of the MAPbI₃ cell decreased to 30% of the initial value after reserving for 112 d under the same test conditions. FA⁺ and Cs⁺ co-doping also significantly improved the thermal and moisture resistance of the cells. Cs_0.05MA_0.35FA_0.6PbI₃ PSCs remain 99% and 84% of initial PCE after aging for 96 h at (85±5) ℃ and 20%-30% relative humidity, (20±5) ℃ and 80%-90% relative humidity in the dark, respectively. In contrast, PCEs of MAPbI₃ PSCs under the same conditions remain only 70% and 56%. This study provides a reference for the preparation of highly efficient and ultra-long stable mixed cation solar cells in the air.