Ligand-modified synthesis of shape-controllable and highly luminescent CsPbBr3 perovskite nanocrystals under ambient conditions

Abstract

All-inorganic CsPbBr₃ perovskite nanocrystals with well-defined morphology have attracted considerable attention due to their unique size/shape-dependent optical properties. However, the formation mechanism of CsPbBr₃ nanocubes (NCs) and nanorods (NRs) remains unknown. Herein, we report a simple room-temperature ligand-mediated synthesis of high-quality CsPbBr₃ NCs and NRs by exploiting the synergistic effect of oleic acid (OA), 1-octanethiol (OT) and n-octylamine (OTAm) ligands. High-resolution transmission electron microscopy (HRTEM) images and density-functional theory (DFT) calculations reveal the shape transformation mechanism between CsPbBr₃ NCs and NRs with the variation of an OTAm/OT mole ratio. The obtained CsPbBr₃ NRs exhibit tunable aspect ratios of 1.6–7.5, and the optimal photoluminescence quantum yield (PLQY) can reach up to 91.2%. Most importantly, the universality of alkyl amine ligands for modifying the shape and optical properties of CsPbBr₃ nanocrystals was also demonstrated. A white light emitting diode (WLED) is fabricated by combining the green-emitting CsPbBr₃ NRs and commercial red phosphors with a blue chip, which shows a bright white light and wide colour range (121.2% of National Television System Committee (NTSC) standard). This work offers a reliable reference for precisely modifying the morphology of thCsPbBr₃ nanocrystals, which will accelerate their commercial application process in the optoelectronic field.