Space‐confined growth of CsPbBr3 nanocrystals in mesoporous KIT‐6 and application in LEDs.

All‐inorganic CsPbX3 (X = Cl, Br, and I) perovskite nanocrystals (NCs) have great application prospects in many fields due to their excellent photoelectric properties. However, CsPbX3 NCs are extremely sensitive to water, heat, light, and oxygen, which leads to dramatic photoluminescence quenching and seriously restricts their future commercial applications. Herein, a novel, simple one‐step solution strategy for synthesizing high‐quality CsPbBr3 NCs was reported. By the combination of the hot‐injection process with the mesoporous template confinement effect of the KIT‐6 matrix, the space‐confined growth of NCs was precisely achieved. The CsPbBr3 NCs encapsulated by KIT‐6 (CsPbBr3@KIT‐6 composite) exhibited a uniform size, a high photoluminescence quantum yield (PLQY) of up to 82%, and a narrow full width at half‐maximum (FWHM) of 24 nm. Most importantly, CsPbBr3@KIT‐6 powder composites had dramatically enhanced light, thermal and water stability in comparison with colloidal CsPbBr3 NCs due to the dual protection of organic ligands and matrix templates. Ultimately, a white light‐emitting diode (LED) device was successfully fabricated by encapsulating a mixture of green‐emitting CsPbBr3@KIT‐6 composite and red‐emitting K2SiF6:Mn4+ phosphor onto a blue‐emitting InGaN LED chip. A color coordinate of (0.327, 0.337) and a wide color gamut of 128% NTSC well demonstrate their potential applications in lighting and display. [ABSTRACT FROM AUTHOR]