Homogenizing LARP Precursor Clusters Enhances Luminance and Efficiency of FAPbBr3 QLEDs.

Perovskite quantum dots (PQDs) hold great promise for next-generation displays owing to their excellent optoelectronic properties and low-cost solution processability. Ligand-assisted reprecipitation (LARP) is a widely adopted room-temperature synthesis method, yet inhomogeneous prenucleation clusters in precursors yield PQDs with broad size distribution and high surface defect density. Herein, we introduce a zwitterionic ligand with multiple coordination sites and strong adsorption energy. It homogenizes prenucleation clusters by regulating the coordination state of lead bromide complexes in precursors, suppressing dynamic ligand dissociation and enabling a homogeneous crystallization pathway. The resulting PQDs show a narrowed emission full width at half-maximum from 25.1 to 21.2 nm and a prolonged photoluminescence lifetime from 22.28 to 57.88 ns. The corresponding perovskite light-emitting diodes achieve a maximum external quantum efficiency of 20.8% (from 5.6%), a peak luminance of 64 005 cd m-2 (from 16 370 cd m-2), and a T50 operational lifetime at 1000 cd m-2 extended from 30 to 309 s. This provides a strategy for the controllable room-temperature synthesis of high-quality PQDs toward the construction of high-performance PeLEDs.