Single-Crystal Thin Films of Cesium Lead Bromide Perovskite Epitaxially Grown on Metal Oxide Perovskite (SrTiO 3 )

Chen, Jie [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States; International
Research Center for Renewable Energy, State Key Laboratory of Multiphase
Flow in Power Engineering, Xi’an Jiaotong University, Shaanxi 710049, P. R. China] (ORCID:0000000220070896); Morrow, Darien J. [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States] (ORCID:0000000289228049); Fu, Yongping [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States] (ORCID:0000000333622474); Zheng, Weihao [Key
Laboratory for Micro-Nano Physics and Technology of Hunan Province,
School of Physics and Electronic Science, Hunan University, Changsha 410082, P. R. China]; Zhao, Yuzhou [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States]; Dang, Lianna [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States]; Stolt, Matthew J. [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States] (ORCID:0000000267040862); Kohler, Daniel D. [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States]; Wang, Xiaoxia [Key
Laboratory for Micro-Nano Physics and Technology of Hunan Province,
School of Physics and Electronic Science, Hunan University, Changsha 410082, P. R. China]; Czech, Kyle J. [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States]; Hautzinger, Matthew P. [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States]; Shen, Shaohua [International
Research Center for Renewable Energy, State Key Laboratory of Multiphase
Flow in Power Engineering, Xi’an Jiaotong University, Shaanxi 710049, P. R. China]; Guo, Liejin [International
Research Center for Renewable Energy, State Key Laboratory of Multiphase
Flow in Power Engineering, Xi’an Jiaotong University, Shaanxi 710049, P. R. China] (ORCID:0000000236715628); Pan, Anlian [Key
Laboratory for Micro-Nano Physics and Technology of Hunan Province,
School of Physics and Electronic Science, Hunan University, Changsha 410082, P. R. China] (ORCID:0000000333353067); Wright, John C. [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States]; Jin, Song [Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States] (ORCID:0000000186937010)

doi:10.1021/jacs.7b07506

Abstract

All‐inorganic lead halide perovskite nanocrystals (NCs) have great optoelectronic properties with promising applications in light‐emitting diodes (LEDs), lasers, photodetectors, solar cells, and photocatalysis. However, the intrinsic toxicity of Pb and instability of the NCs impede their broad applications. Shell‐coating is an effective method for enhanced environmental stability while reducing toxicity by choosing non‐toxic shell materials such as metal oxides, polymers, silica, etc. However, multiple perovskite NCs can be encapsulated within the shell material and a uniform epitaxial‐type shell growth of well‐isolated NCs is still challenging. In this work, lead‐free vacancy‐ordered double perovskite Cs₂SnX₆(X = Cl, Br, and I) shells are epitaxially grown on the surface of CsPbX₃NCs by a hot‐injection method. The effectiveness of the non‐toxic double perovskite shell protection is demonstrated by the enhanced environmental and phase stability against UV illumination and water. In addition, the photoluminescence quantum yields (PL QYs) increase for the CsPbCl₃and CsPbBr₃NCs after shelling because of the type I band alignment of the core/shell materials, while enhanced charge transport properties obtained from CsPbI₃/Cs₂SnI₆core/shell NCs are due to the efficient charge separation in the type II core/shell band alignment.

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