One-Step Melt Closed Mesoporous SiO2 for Large-Scale Synthesis of Confined CsPbX3 (X = Cl, Br, and I) Quantum Dots and LED Applications

All-inorganic perovskite quantum dots (PQDs) have great application prospects in many fields because of their excellent photoelectric properties. However, their instability in water, oxygen, light, and heat leads to photoluminescence quenching, and the method of colloidal synthesis makes it difficult to achieve a large-scale synthesis, limiting practical applications. Herein, we synthesize CsPbX3@SiO2 with excellent optical performance and stability by closing the mesopores of SiO2 at high temperature in air atmosphere. Moreover, the photoluminescence quantum yield (PLQY) of CsPbBr3@SiO2 is as high as 80.6%, and the full width at half-maximum (fwhm) is 23 nm. In addition, CsPbX3@SiO2 shows excellent stability as a result of the melt closed mesoporous SiO2, and the relative electroluminescence intensity of composites remains 125.6% of the original after operating at 85% humidity and 85 °C for 360 h. Neutral white light was obtained by assembling blue LEDs with green and red composite materials, whose color temperature (CCT) was 4995 K and color gamut covered 134.6% of NTSC. Impressively, the preparation process of mesoporous SiO2 and CsPbX3@SiO2 is simple and low-cost. Furthermore, it can enable large-scale preparation and shows great potential in practical applications.