Hybrid-Protected\nPerovskite Quantum Dot Films with\nUltra-High Efficiency and Stability for LED Backlighting

All-inorganic lead halide perovskite quantum dots (PQDs)\nhave emerged\nas highly promising materials for photonic and optoelectronic devices,\nsolar cells, and photocatalysts. However, PQDs encounter instability\nand color separation issues because of ion diffusion. Current strategies\nmainly address stability in green CsPbBr<sub>3</sub> PQDs, with limited\nfocus on the red-mixed halide PQDs because of their inferior stability\ncompared with green PQDs. Our study provides a new dual-protection\nmethodology for synthesizing high-efficiency green and red mixed-halide\nPQD films. Red CsPb(Br<sub>0.4</sub>I<sub>0.6</sub>)<sub>3</sub> and\ngreen CsPbBr<sub>3</sub> PQDs are embedded with silicone resin and\nthen incorporated with poly(methyl methacrylate) (PMMA) matrix to\nform red and green PQDs@silicone/PMMA films. The high photoluminescence\nquantum yield (PLQY) and great stability are recorded for the pure-red\nPQD polymer film. The ultrabright green CsPbBr<sub>3</sub> PQDs@silicone/PMMA\nfilm was also successfully fabricated with an outstanding PLQY beyond\n94%. These films exhibited enhanced stability against thermal and\nenvironmental degradation, attributed to the dense protective layer\nof silicone resin and PMMA matrices by the formation of Si–halide\nand Pb–O bonds, thereby reducing surface defects. Theoretical\ncalculations reveal that combining silicone resin and PMMA improves\nPb–O interactions, eliminating uncoordinated Pb<sup>2+</sup> and enhancing PQD stability. Applied to white light-emitting diodes\n(WLEDs), these films demonstrated a broad color gamut of 143.4%, indicating\ntheir potential for efficient WLED backlighting.