CsPbBr₃@Glass@SiO₂ Composite Materials with Ultrahigh Water Resistance and Thermal Reversibility of Photoluminescence

Perovskite quantum dots usually possess excellent optical properties, such as high color purity, high photoluminescence quantum yield, and tunable emission wavelength. However, their relatively low stability against heat, water, oxygen, and light hinders their practical applications in the field of optoelectronic devices. Herein, melt-quenching and heat treatment crystallization methods are used to fabricate the CsPbBr₃@glass. Atomic layer deposition and the sol–gel method are applied to encapsulate the CsPbBr₃@glass with a dense SiO₂ layer and hydrophobic SiO₂ layer, respectively, to further improve the water resistance, thermal reversibility of photoluminescence, and photostability. The CsPbBr₃@glass@ASG can be synthesized with the triple layer encapsulation of the glass matrix, dense SiO₂ layer, and hydrophobic SiO₂ layer. During the water resistance test for seven weeks, CsPbBr₃@glass@ASG can preserve ≈100% of initial PL intensity. Similarly, it can preserve ≈100% of PL intensity after five continuous heating–cooling cycles between 30 and 100 °C. In addition, the internal and external quantum efficiencies of CsPbBr₃@glass@ASG can still be maintained at 42.0% and 33.7%, respectively. Results indicate that CsPbBr₃@glass@ASG can provide a balance between optical properties and extrinsic stability successfully, thereby becoming a potential candidate material for practical applications related to optoelectronic devices in the future.