From Heterostructures to Solid‐Solutions: Structural Tunability in Mixed Halide Perovskites
From Heterostructures to Solid‐Solutions: Structural Tunability in Mixed Halide Perovskites
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从异质结构到固体解决方案：混合卤化物钙钛矿的结构可调性
DOI：
10.1002/adma.202205923
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发表时间：
2023
影响因子：
29.4
通讯作者：
Mirkin, Chad A.
中科院分区：
文献类型：
--
作者：
Shin, Donghoon;Lai, Minliang;Shin, Yongjin;Du, Jingshan S.;Jibril, Liban;Rondinelli, James M.;Mirkin, Chad A.
基于卤化物钙钛矿的器件的稳定性、可靠性和性能取决于器件使能材料的结构、组成和颗粒大小。事实上，多组分钙钛矿晶体中的离子混合程度，尽管难以控制，但却是决定性能的关键因素。本文采用一种称为蒸发-结晶聚合物PEN光刻的新方法，合成并系统地研究了Cs0.5FA0.5PbX3(FA=甲酰胺；X=卤化物阴离子，ABX3)晶体的离子混合程度与尺寸、温度和组成的关系。这些实验已经发现了一种异质结构形态，其中A位的阳离子Cs和FA分别被分成核心层和边缘层。模拟和实验结果表明，这种异质结构的形成是两种离子在溶液中的溶解度差异和Cs-FA离子偏析的热效应共同作用的结果。这种偏析倾向可以通过减小晶体尺寸(<；60 nm)或提高温度来克服，以形成固溶体。最后，这些工具被用来识别和合成Cs0.5FA0.5Ph(Br/I)3的固溶体纳米晶，与它们的块体相比较，这些固溶体纳米晶显著地抑制了光致阴离子的迁移，为精心设计光稳定性光电材料提供了一条途径。
The stability, reliability, and performance of halide‐perovskite‐based devices depend upon the structure, composition, and particle size of the device‐enabling materials. Indeed, the degree of ion mixing in multicomponent perovskite crystals, although challenging to control, is a key factor in determining properties. Herein, an emerging method termed evaporation–crystallization polymer pen lithography is used to synthesize and systematically study the degree of ionic mixing of Cs0.5FA0.5PbX3(FA = formamidinium; X = halide anion, ABX3) crystals, as a function of size, temperature, and composition. These experiments have led to the discovery of a heterostructure morphology where the A‐site cations, Cs and FA, are segregated into the core and edge layers, respectively. Simulation and experimental results indicate that the heterostructures form as a consequence of a combination of both differences in solubility of the two ions in solution and the enthalpic preference for Cs–FA ion segregation. This preference for segregation can be overcome to form a solid‐solution by decreasing crystal size (<60 nm) or increasing temperature. Finally, these tools are utilized to identify and synthesize solid‐solution nanocrystals of Cs0.5FA0.5Pb(Br/I)3that significantly suppress photoinduced anion migration compared to their bulk counterparts, offering a route to deliberately designed photostable optoelectronic materials.