Synthesis and electronic structure study on CsPbBr3 nanoplatelets: Thickness manipulation using surface ligands

Abstract

Cesium Lead Halide based Perovskites have received significant attention due to their potential application in all inorganic solar cells. To date, there is only limited literature on their anisotropic nanostructures. Here, we report synthesis of 2D nanostructures of CsPbBr3 with thickness of few monolayers (MLs). Due to size quantization, the 2D nanostructure showed a blue shifted absorption from bulk absorption. We manipulate acid: amine (capping agents) ratios to achieve a monolayer level thickness control as evidenced by absorption spectroscopy and TEM analysis. The thickness of 1 ML-4 ML could be seamlessly controlled by varying the ratio. The study shows rich solution phase reaction dynamics during growth with size evolution over time. Additionally, we also compute band structure to validate the effect of size quantization on electronic structure for NPLs investigated. This study opens up possibility of synthesis of these nanostructures with good reaction control over growth of NPLs and also sheds light on complex acid base chemistry that exists in reaction.