Solvothermal synthesis of perovskite CsPbCl3 nanoplates and improved photoluminescence performance through postsynthetic treatment

The controllable synthesis of two-dimensional all-inorganic lead halide perovskite (CsPbX3, X = Cl, Br and I) nanoplates (NPLs) has attracted wide attention of researchers. However, the direct synthesis of high-quality CsPbCl3 NPLs with controllable morphology still faces a challenge. Herein we report a solvothermal method to directly synthesize CsPbCl3 NPLs. By varying solvothermal reaction time, the thickness of the NPLs has be successfully adjusted from 2.8 to 3.6 nm, and the red shift of the photoluminescence (PL) emission from 391 to 402 nm has been realized. Subsequently, effective post-treatment on the as-prepared CsPbCl3 NPLs using CoCl2 results in the greatly enhancement of PL quantum yield (PLQY) from original 14.09 to final 50.4%, showing the best PLQY among all CsPbCl3 NPLs samples to date. This work not only provides a reliable process for the controllable preparation of CsPbCl3 NPLs, but also supplies more selectivity for the post-treatment of CsPbCl3 nanocrystals using chloride compounds.