One-Pot Synthesis of Highly Stable CsPbBr₃@SiO₂ Core–Shell Nanoparticles

The practical applications of CsPbX₃ nanocrystals (NCs) have been limited by their poor stability. Although much effort has been devoted to making core-shell nanostructures to enhance the stability of CsPbX₃ NCs, it is still very difficult to coat CsPbX₃ NCs with another material on a single-particle level. In this work, we report a facile one-pot approach to synthesize CsPbBr₃@SiO₂ core-shell nanoparticles (NPs), in which each core-shell NP has only one CsPbBr₃ NC. The formation process has been carefully monitored. It has been found that the formation rates, determined by reaction temperature, precursor species, pH value, etc., of both CsPbBr₃ and SiO₂ are critical for the successful preparation of core-shell NPs. Thanks to the protection of SiO₂ shell, the product shows much higher long-term stability in humid air and enhanced stability against ultrasonication treatment in water than that of naked CsPbBr₃ NCs. This work not only provides a robust method for the preparation of core-shell nanostructures but also sheds some light on the stabilization and applications of CsPbX₃ NCs.