An amine-mediated synthesis strategy for 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 their thickness. We develop a colloidal synthesis route for CsPbBr₃ perovskite NPLs using different degrees of amine. The shapes of the 2D CsPbBr₃ perovskites are systematically engineered into rectangular, truncated and hexagonal NPLs using primary, secondary and tertiary amines, respectively, in the synthesis, together with oleylamine. The lateral size of the NPLs is tuned by varying the amine degree, 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 CsPbBr₃ perovskite NPLs using different degrees of amine, and they are suitable for optoelectronic applications.