Pure red CsPbBr_0.96I_2.04/SiO₂ core/shell nanocrystals with simultaneous high efficiency and stability for Mini-LEDs

Pure red mixed halide CsPbBr3-xIx perovskite nanocrystals (NCs) exhibit a high photoluminescence quantum yield (PLQY) and narrow full width at half maximum (FWHM), but there are phase stability issues that hinder their application in displays. In this work, we propose pure red CsPbBr0.96I2.04/SiO2 core/shell NCs by using (3-aminopropyl)triethoxysilane as the surface ligand and silicon source via a hot-injection and in situ hydrolytic process. The CsPbBr0.96I2.04/SiO2 NCs not only show excellent optical properties with a near-unity PLQY but also exhibit high stability against moisture, blue light, and heat. Pure red CsPbBr0.96I2.04/SiO2 NC inks were prepared by dispersing CsPbBr0.96I2.04/SiO2 NCs into a mixed solvent of toluene and dodecane and used to inkjet print NC color conversion films (NC-CCFs) with excellent luminescence uniformity and high stability. Finally, white-emitting Mini-LEDs were fabricated by combining pure red CsPbBr0.96I2.04/SiO2 NC-CCFs with green CsPbBr3/SiO2 NC-CCFs and blue Mini-LED chips, showing a high external quantum efficiency (EQE) of 24.8% and an ultrawide color gamut of 132.58% NTSC and 99.2% Rec. 2020 standards. This demonstrates the potential of pure red CsPbBr0.96I2.04/SiO2 NCs for Mini-LED backlights.