Stable, Three-Primary Color CsPbX₃‑Nanocrystal/SiO₂ Luminescent Composites via Melt Recrystallization for Backlight Light-Emitting Diodes

CsPbX₃ (X = Cl, Br, and I) perovskite nanocrystals (PNCs) have been recognized as potential optoelectronic materials due to their excellent optical characteristics. However, their poor stability limits their further practical application, and research on their stability improvement mainly concentrated on green-emitted CsPbBr₃ PNCs. Herein, high-stable red, green, and blue three-primary color CsPbX₃-nanocrystal/SiO₂ (PNC/SiO₂) luminescent composites have been synthesized by a simple high-temperature melt-crystallization method, which did not use any solvent or ligand. The sintering conditions for PNC/SiO₂ composites were optimized according to the X-ray diffraction and photoluminescence (PL) spectra, which ensured the composite structures and achieved higher PL quantum yield. The optimized red, green, and blue composites can remain at 99%, 90%, and 82% PL intensity after 15 heating loops, performing good thermal stability. To check the application potential, the optimized composites were fabricated as red, green, and blue light-emitting diodes (LEDs), showing high color purity to consist of a wide color gamut. The red, green, and blue LEDs remained at 83%, 82%, and 96% emission intensity and kept their color coordinates after a long working duration, showing excellent stability. The excellent stability and relatively higher color purity of the PNC/SiO₂ composites indicate their great potential for commercial background display applications.