论文标题
卤化物钙钛矿中对稳定性的追求：单价阳离子和表面和散装自我修复的关键
The pursuit of stability in halide perovskites: the monovalent cation and the key for surface and bulk self-repair
论文作者
论文摘要
我们发现，对于每个不同的APBBR3单晶的降解和愈合之间的降解和愈合之间的显着差异（A = CH3NH3+，甲基铵（MA）； HC（NH2）2+，Formamidinium（FA）；和Cesium，CS+）。使用1和2光子的显微镜和光漂白，我们得出的结论是，动力学主导了表面，并且热力学构成了大量稳定性。千篇一律的成像显微镜以及其他几种方法的结果都将光泽片的卤化物钙钛矿状态（HAP）与其修饰的光学和电子特性有关。 A阳离子类型强烈影响动力学和恢复和降解的热力学：FA可以通过更快的自我修复来治愈最佳的散装材料。 CS+最好保护表面，是A阳离子的挥发性最小，可能是通过O-Passivation； MA通过甲胺通过甲基胺的静缺损而钝化，该缺陷与PB2+结合。 DFT模拟不仅可以洞悉后一个结论，而且还显示了BR3缺陷的重要性和稳定性。这些结果合理地使用混合A量材料来优化太阳能电池稳定性和基于HAP的设备的整体性能，并为设计新的HAP变体提供了基础。
We find significant differences between degradation and healing at the surface or in the bulk for each of the different APbBr3 single crystals (A=CH3NH3+, methylammonium (MA); HC(NH2)2+, formamidinium (FA); and cesium, Cs+). Using 1- and 2-photon microscopy and photobleaching we conclude that kinetics dominate the surface, and thermodynamics the bulk stability. Fluorescence-lifetime imaging microscopy, as well as results from several other methods, relate the (damaged) state of the halide perovskite (HaP) after photobleaching to its modified optical and electronic properties. The A cation type strongly influences both the kinetics and the thermodynamics of recovery and degradation: FA heals best the bulk material with faster self-healing; Cs+ protects the surface best, being the least volatile of the A cations and possibly through O-passivation; MA passivates defects via methylamine from photo-dissociation, which binds to Pb2+. DFT simulations not only provide insight into the latter conclusion, but also show the importance and stability of the Br3- defect. These results rationalize the use of mixed A-cation materials for optimizing both solar cell stability and overall performance of HaP-based devices, and provide a basis for designing new HaP variants.
