Enhancing stability of CsPbBr ₃ nanocrystals light‐emitting diodes through polymethylmethacrylate physical adsorption

Boosting the efficiency and lifetime of all inorganic metal halide perovskite nanocrystals (PeNCs) based light-emitting diodes (PeLEDs) will promote the application of PeNCs in displays and lighting. However, achieving high-stability CsPbBr₃ NCs is still a critical challenge. In this study, a physical adsorption of polymethylmethacrylate (PMMA) on the surface of CsPbBr₃ NCs is proven effective to enhance CsPbBr₃ NCs stability by reducing the surface energy and preventing the attack of water and oxygen molecules. It also alleviates the energy transfer between neighboring NCs and greatly reduces the thin film roughness by suppressing the agglomeration of the CsPbBr₃ NCs within films. Specifically, compared with CsPbBr₃ NCs without PMMA adsorption, the photostability under the illumination of continuous ultraviolet light (96 hours) and storage stability under 0 °C (60 days) of the proposed CsPbBr₃ NCs with PMMA adsorption are therefore improved by >10 times and four times, respectively. Moreover, since the energy transfer between CsPbBr₃ NCs and the agglomeration of CsPbBr₃ NCs within films have been suppressed dramatically by the physical absorbed PMMA, the maximum luminance of as-fabricated LED devices is promoted from 5000 to 13,800 cd m⁻² with alleviated roll-off effect. The operational lifetime of the LED devices is also improved by 5.7 times owing to PMMA preventing the attack of water and oxygen molecules.