title: Nanocube Superlattices of Cesium Lead Bromide Perovskites and Pressure-Induced Phase Transformations at Atomic and Mesoscale Levels.
abstract: Lead halide perovskites are promising materials for a range of applications owing to their unique crystal structure and optoelectronic properties. Understanding the relationship between the atomic/mesostructures and the associated properties of perovskite materials is crucial to their application performances. Herein, the detailed pressure processing of CsPbBr3perovskite nanocube superlattices (NC-SLs) is reported for the first time. By using in situ synchrotron-based small/wide angle X-ray scattering and photoluminescence (PL) probes, the NC-SL structural transformations are correlated at both atomic and mesoscale levels with the band-gap evolution through a pressure cycle of 0 ↔ 17.5 GPa. After the pressurization, the individual CsPbBr3NCs fuse into 2D nanoplatelets (NPLs) with a uniform thickness. The pressure-synthesized perovskite NPLs exhibit a single cubic crystal structure, a 1.6-fold enhanced photoluminescence quantum yield, and a longer emission lifetime than the starting NCs. This study demonstrates that pressure processing can serve as a novel approach for the rapid conversion of lead halide perovskites into structures with enhanced properties.
authors.affiliation: Department of Chemistry, Brown University, 324 Brook St. Providence, RI, 02912, USA.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Nagaoka
authors.affiliation: Department of Chemistry, Brown University, 324 Brook St. Providence, RI, 02912, USA.
authors.forename: Katie
authors.initials: K
authors.lastname: Hills-Kimball
authors.affiliation: Department of Chemistry, Brown University, 324 Brook St. Providence, RI, 02912, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Tan
authors.affiliation: Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, 14853, USA.
authors.forename: Ruipeng
authors.initials: R
authors.lastname: Li
authors.affiliation: Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, 14853, USA.
authors.forename: Zhongwu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Brown University, 324 Brook St. Providence, RI, 02912, USA.
authors.forename: Ou
authors.initials: O
authors.lastname: Chen
keywords: halide perovskites; nanocrystal superlattices; phase transitions; photoluminescence; pressure-processing