Epitaxial CsPbBr<sub>3</sub> Perovskite - Cs<sub>3</sub>Cu<sub>2</sub>Br<sub>5</sub> Ternary Metal Halide Nanoheterostructures.

Vighnesh, Kunnathodi; Hassan, Md Samim; Li, Zhuo; Sokolova, Anastasiia V; Portniagin, Arsenii S; Liu, Haochen; Zhao, Xin; Wu, Ye et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Designing epitaxial nanoheterostructures of metal halide perovskites with other semiconductor materials offers a way to tune their optical properties and charge carrier dynamics. However, achieving an epitaxial interface between them presents a significant challenge due to the differences in their bonding nature, growth kinetics, and lattice mismatch. We synthesized a colloidal epitaxial nanoheterostructure with a pseudo type-II band alignment comprising CsPbBr<sub>3</sub> perovskite and Cs<sub>3</sub>Cu<sub>2</sub>Br<sub>5</sub> ternary metal halide. A hot-injection synthesis route was developed that offers a common reaction pathway for the formation of both kinds of nanocrystals, facilitating the heteronucleation of Cs<sub>3</sub>Cu<sub>2</sub>Br<sub>5</sub> on CsPbBr<sub>3</sub> nanocubes through shared Cs<sup>+</sup> and Br<sup>-</sup> sublattices. The crystallographic planes that align across the interface, having minimum lattice mismatch, establish the epitaxial relationship between the constituting counterparts of the nanoheterostructure. This study presents a method for utilizing the Cs and Br sublattices to create an epitaxial interface, enabling development of various combinations of perovskite-semiconductor nanoheterostructures.