Fabrication of blue-emitting CH3NH3PbBr3 nanocrystals: Effects of dipole moment and oxygen functional groups in precipitation solvents on the crystal growth and optical properties of CH3NH3PbBr3 nanocrystals

Abstract

In this study, blue-emitting CH3NH3PbBr3 nanocrystals (NCs) were achieved by changing the precipitation solvent used in ligand-assisted re-precipitation (LARP) process from a non-polar to a polar solvent. As the dipole moment of precipitation solvent (Sol. B) with oxygen functional groups increased, the photoluminescence (PL) spectrum of CH3NH3PbBr3 NCs was blue-shifted and the crystal size decreased. The high dipole moment of Sol. B increased the interaction between the ligands and Sol. B, promoting the growth of CH3NH3PbBr3 bulk particles rather than CH3NH3PbBr3 NCs. This decreased the monomer concentration in the reaction vessel, thereby limiting the crystal growth of CH3NH3PbBr3 NCs. This study demonstrates that blue-emitting CH3NH3PbBr3 NCs can be achieved by controlling the interaction between the ligands and Sol. B through variations in the dipole moment of Sol. B, and that the presence of oxygen functional groups is essential for tuning the optical bandgap of CH3NH3PbBr3 NCs. © 2025 Elsevier Inc.