Ab Initio Study of Interaction of Water, Hydroxyl Radicals, and Hydroxide Ions with CH3NH3PbI3 and CH3NH3PbBr3 Surfaces
Ab Initio Study of Interaction of Water, Hydroxyl Radicals, and Hydroxide Ions with CH3NH3PbI3 and CH3NH3PbBr3 Surfaces
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DOI：
10.1021/acs.jpcc.5b07000
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发表时间：
2015-09
影响因子：
3.7
通讯作者：
Linghai Zhang;P. Sit
中科院分区：
文献类型：
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作者：
Linghai Zhang;P. Sit
尽管在过去的几年里，钙钛矿太阳能电池取得了巨大的突破，但钙钛矿的降解一直是一个巨大的问题。近年来，许多实验研究表明有机-无机卤化物钙钛矿材料对湿空气敏感，并提出了几种降解机理。然而，钙钛矿的分解过程只有一部分人知道，也存在争议。本文采用密度泛函理论计算方法，对CH3NH3PbI3和CH3NH3PbBr3(110)表面进行了范德华修正前后的理论计算，研究了它们的表面结构和退化机理。计算结果表明，CH3NH3+(MA)离子优先取向，NH3基团指向表面。这使得MA阳离子和卤化物之间形成了更多的氢···卤化物氢键。此外，水分子、羟基自由基和氢氧离子与钙钛矿的相互作用也得到了较好的结果。
Although there have been tremendous breakthroughs in perovskite solar cells over the past few years, degradation of perovskite has been a huge problem. Recently, a number of experimental studies have demonstrated that organic–inorganic halide perovskite materials are sensitive to humid air, and several degradation mechanisms have been proposed. However, the decomposition process of perovskites is only partially known and controversial. In this paper, we theoretically study the structures of the tetragonal CH3NH3PbI3 and CH3NH3PbBr3 (110) surfaces and the degradation mechanism using density functional theory calculations both with and without the van der Waals correction. The computed results indicate that the CH3NH3+ (MA) cations preferentially orient with the NH3 group pointing into the surface. This allows the formation of more hydrogen···halide hydrogen bonds between the MA cations and the halides. Moreover, the interactions of water molecules, hydroxyl radicals, and hydroxide ions with the perovskite ...