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.