Recently, the structural stability of all-inorganic halide perovskite nanocrystals has been significantly enhanced. To understand the enhancement, we developed surface-passivation models for cubic CsPbBr3 nanocrystals with anionic (oleate) and cationic (oleylammonium) organic ligands based on first-principles calculations and nuclear magnetic resonance investigations. We propose that the (100) surface is initially terminated with oleate ligand complexes on PbBr2(100) surfaces. Also, the ligand transition to oleylammonium on the Pb-rich surfaces is expected due to the addition of metal halides (ZnBr2) during colloidal synthesis. The significant improvement in the structural stability of the cationic ligand-passivated CsPbBr3 nanocrystals was attributed to the suppressed exposure of the merging-vulnerable (110) surface, caused by the large difference in formation energy between the ligand-passivated (100) and Br-passivated (110) surfaces.

中文翻译：

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全无机铯卤化铅钙钛矿纳米晶体的稳定性起源和从阴离子到阳离子表面配体钝化的转变。

近来，全无机卤化物钙钛矿纳米晶体的结构稳定性已显着增强。为了了解这种增强作用，我们基于第一性原理计算和核磁共振研究，开发了具有阴离子（油酸酯）和阳离子（油铵）有机配体的立方CsPbBr3纳米晶体的表面钝化模型。我们建议（100）表面最初被PbBr2（100）表面上的油酸酯配体配合物终止。另外，由于在胶体合成过程中添加了金属卤化物（ZnBr2），因此预期在富含Pb的表面上，配体会转变为氨溴铵。阳离子配体钝化的CsPbBr3纳米晶体在结构稳定性方面的显着改善归因于可合并脆弱（110）表面的暴露受到抑制，