Perovskite Quantum Heterostructure Constructed by Halide Mixing between a Single CsPbI 3 Nanocrystal and an Individual CsPbBr 3 Microplate

• Published in: The journal of physical chemistry letters 2024-07, Vol.15 (26), p.6763-6770
• Main Authors: Yuan, Junyang, Hu, Fengrui, Ju, Yu, Li, Si, Zhao, Hao, Zhang, Chunfeng, Gan, Zhixing, Xiao, Min, Wang, Xiaoyong
• Format: Article
• Language: English
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.4c01312

Ion migration is significantly enhanced in lead-halide perovskites with a soft crystal lattice, which can promote the formation of a heterogeneous interface between two such materials with different halide-anion compositions. Here we have deposited a single CsPbI nanocrystal (NC) on top of an individual CsPbBr microplate to create a mixed-halide CsPbBr I (0 < < 3) NC by means of the anion exchange process. The formation of a CsPbBr I /CsPbBr heterostructure is confirmed by the much-enlarged geometric volume of the CsPbBr I NC as compared to the original CsPbI one, as well as by its capability of receiving photogenerated excitons from the CsPbBr microplate with a larger bandgap energy. The quantum nature of this heterostructure is reflected from single-photon emission of the composing CsPbBr I NC, which can also be bulk-like during phase segregation to demonstrate a red shift in the photoluminescence peak that is opposite to the common trend observed in smaller-sized mixed-halide NCs.