Efficient Enhancement of Stability and Luminescence of Three-Dimensional CsPbBr3 Nanoparticles via Ligand-Triggered Transformation into Zero-Dimensional Cs4PbBr6 Nanoparticles

Because of their impressive charge-transport properties, strong light absorption, long carrier diffusion lengths, and long excited-state lifetime, metal halide perovskites have emerged as attractive materials for use in solar cells, light-emitting diodes, and other optoelectronic devices. The extensive research on these materials has paved the way for a new class of materials: low-dimensional metal halide perovskite nanoparticles (NPs). The low-dimensional perovskite NPs have sparked a wave of research for improving the stability and luminescence of their three-dimensional (3D) counterparts. In addition to direct synthesis for low-dimensional materials, the transformation between various structures is another noteworthy approach that can not only provide high-quality materials but also reveal the internal relationships among materials in different dimensions. Herein, the conversion from 3D CsPbBr3 NPs to zero-dimensional (0D) Cs4PbBr6 NPs with the assistance of hexadecyltrimethylammonium bromide was investigated. An exfoliating intermediate stage of ligand insertion occurred during the dimensionality transformation. The stability and photoluminescence were an evident enhancement for the CsPbBr3 NPs. In this work, the chemical transformation procedure was systematically explored by adapting the ligand type and concentration, and the resulting products had significantly improved stability and photoluminescence, which indicates promising application prospects.