Homogeneous Surface Attachment of Functional Ligands for Compatible Perovskite Nanoparticle Crystallization

Abstract

Metal halide perovskite-based nanoparticles exhibit high quantum yields (QYs) compared to their bulk phases due to an increased stability, a bright exciton triplet state, and superfluorescence properties. This study suggests a strategy to synthesize pure red-emitting perovskite quantum dots (PQDs) at low-temperatures by controlling the molarities of the monodentate ligands in dimethylformamide (DMF) as a polar-solvent. Ligand compatibility was analyzed based on the LaMer model. A range of various conditions are identified using plots of the compatible/incompatible synthetic conditions. The red PQD with the highest iodine content exhibits an QY of 76.9%, along with a strong photoluminescence intensity. This exhibits no discoloration after 90 h, and maintain 88% of the luminescence intensity, indicating almost no change in CIE coordinates. This confirms that defects of vacancies on the perovskite surface are filled with the appropriate ligand. Overall, this approach provides a facile platform for obtaining high quality DMF-based pure-red PQDs.

Keywords: perovskite, quantum dot, nanoparticles, red characteristics, LaMer model