Very recently, two-dimensional (2D) perovskite nanosheets (PNSs), taking the advantages of perovskite as well as the 2D structure properties, have received an enormous level of interest throughout the scientific community. In spite of this incredible success in perovskite nanocrystals (NCs), self-assembly of many nanostructures in metal halide perovskites has not yet been realized, and producing highly efficient red-emitting PNSs remains challenging. In this Letter, we show that by using CsPbBrI₂ perovskite nanoparticles (NPs) as a building block, PNSs can emerge spontaneously under high ambient pressure via template-free self-assembly without additional complicated operation. It is found that the formation of PNSs is ascribed to the high pressure that provides the driving force for the alignment of NPs in solution. Because of the disappearance of the grain boundaries between the adjacent NPs and increased crystallinity, these PNSs self-assembled from NPs exhibit enhanced properties compared to the initial NPs, including higher PL intensity and remarkable chemical stability toward light and water.

中文翻译：

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通过自组装在溶液中将CsPbBrI ₂纳米颗粒压力驱动转变为稳定的纳米片

最近，二维（2D）钙钛矿纳米片（PNSs）凭借钙钛矿的优势以及2D结构特性，在整个科学界引起了极大的兴趣。尽管钙钛矿纳米晶体（NCs）取得了令人难以置信的成功，但尚未实现金属卤化物钙钛矿中许多纳米结构的自组装，而生产高效的发红光的PNS仍然具有挑战性。在这封信中，我们显示了通过使用CsPbBrI ₂钙钛矿纳米颗粒（NPs）作为组成部分，PNS可以通过无模板自组装在高环境压力下自发出现，而无需额外的复杂操作。发现PNS的形成归因于高压，该高压为溶液中NP的排列提供驱动力。由于相邻NP之间晶界的消失和结晶度的提高，与初始NP相比，这些由NP自组装的PNS表现出增强的性能，包括更高的PL强度以及对光和水的显着化学稳定性。