CsPbI3 quantum dots with synergistic passivation and encapsulation for high-performance and stable red LEDs

Metal halide perovskite quantum dots (PQDs) are promising for optoelectronic applications, yet CsPbI 3 PQDs face challenges from intrinsic defects, poor stability, and limited processability. Herein, we report a dual-ligand synergistic passivation strategy (DLSPS) combining La(acac) 3 and benzamide, coupled with EPDM encapsulation. The strategy employs La(acac) 3 for lattice defect compensation and La 3 + fills Pb 2+ vacancies while benzamide for surface passivation, synergistically suppressing non-radiative recombination and ion migration. EPDM encapsulation forms a hydrophobic network, enhancing processability and environmental robustness. Density functional theory (DFT) calculations confirm strong and selective binding of ligands to CsPbI 3 , which achieve a high PLQY of 70.11%, narrow emission at 688 nm, and exceptional stability under thermal, aqueous, and UV stresses. Red LEDs fabricated with CsPbI 3 (DLSPS)/EPDM films deliver deep-red emission (CIE: 0.73, 0.27) and retain 70% of initial intensity after 72 h operation. This scalable strategy bridges material engineering with device fabrication, advancing industrialization of perovskite-based red LEDs.