| Summary: | Practical applications of CsPbX<sub>3</sub> nanocrystals (NCs) are limited by their poor stability. The formation of a heterojunction between CsPbX<sub>3</sub> NCs and oxides is an effective means to protect perovskite from polar solvents and other external factors. Significantly improving the stability and photocatalytic properties of the core/shell perovskite is very important for its application in photoelectric and photocatalytic technology. Here, we report the synthesis of asymmetrical CsPbBr<sub>3</sub>/TiO<sub>2</sub> core–shell heterostructure NCs at the single-particle level by hot-injection liquid-phase synthesis and sol–gel method, where each CsPbBr<sub>3</sub> NCs is partially covered by titanium dioxide. We tested not only the optical properties of the material but also the electrochemical impedance and photocurrent density of the material in sodium sulfate solution. It is shown that the type II arrangement is generated at the heterogeneous interface, which greatly facilitates the separation of electron–hole pairs and increases the carrier transport efficiency. Compared with CsPbBr<sub>3</sub> NCs, CsPbBr<sub>3</sub>/TiO<sub>2</sub> has higher photocatalytic efficiency. More crucially, due to the protection of the titanium dioxide shell, the product has higher long-term stability in humid air compared with bare CsPbBr<sub>3</sub> NCs. The asymmetrical core–shell heterostructure prepared in this study not only improves the stability of CsPbX<sub>3</sub> NCs but also provides some ideas for optoelectronic device applications and TiO<sub>2</sub>-based photocatalysts.
|
|---|