Amine-Mediated Synthesis Strategy of Shape Controlled Cesium Lead Halide Perovskite Nanoplatelets

Abstract

Colloidal nanoplatelets (NPLs) represent a unique class of two-dimensional (2D) nanomaterials where quantum confinement originates from the thickness. We develop a colloidal synthesis route of CsPbBr3 perovskite NPLs using different degrees of amines. Shapes of the 2D CsPbBr3 perovskites are systematically engineered into rectangular, truncated and hexagonal NPLs using primary, secondary and tertiary amines respectively in the syntheses together with oleylamine. The lateral size of the NPLs is tuned by varying the degrees of amines, while the thickness of the NPLs remains around just a few unit cells suggesting a strong quantum confinement regime. The NPLs exhibit excitonic absorption features, narrow photoluminescence peaks and shape-dependent photoluminescence decay lifetimes showing a maximum for the hexagonal NPLs. A high photoluminescence quantum yield of 59% was achieved for the hexagonal NPLs synthesized using the tertiary amine. Our synthesis method provides a facile route to rationally control the shape of the CsPbBr3 perovskite NPLs using different degrees of amines suitable for optoelectronic applications.