Highly luminescent CsPbX3/PMMA (X=Br, I) composites with improved stability for full-color Micro-LED displays

Inorganic metal halide perovskite quantum dots (PQDs) have recently emerged as promising candidates for color conversion materials in Micro-LED displays, due to their outstanding color purity, high absorption coefficient, tunable emission wavelength. However the inferior stability and undesirable photoluminescence quantum yield (PLQY) restrict their particle applications. Herein, CsPbX3/PMMA (X = Br, I) composites with improved stability and optical performance were successfully prepared by a general and mild in-situ polymerization strategy. The ester carbonyl (CO) group in MMA formed complexes with Pb2+, leading to the in-situ thermal polymerization of polymethyl methacrylate (PMMA) under the action of the initiator. The multifunctional PMMA can efficiently passivate halogen vacancies while acting as a barrier against the degradation caused by heat, water, and oxygen. As a result, the PLQYs and stability of PMMA-coated CsPbX3 PQDs have been significantly improved. When implementing CsPbX3/PMMA/PDMS composites as color conversion layers in Micro-LEDs, they achieve an impressive color gamut of 127.23% with excellent stability. We believe our work will stimulate the exploration of perovskite/polymer composites for industrial Micro-LED applications. •A universal and effective strategy is developed to increase the optical properties and stability of metal halide quantum dots.•The PLQYs of PMMA-coated CsPbBr3 and CsPbI3 can be increased by 1.18 and 1.23 times, respectively.•The Micro-LED displays based on CsPbX3/PMMA composites not only have a wide color gamut of 127.23% NTSC, but also have excellent working stability.