Encapsulation of CsPbBr in TiO Microcrystals to Enhance Environmental Stability.

All-inorganic lead halide perovskite has emerged as an attractive semiconducting material due to its unique optoelectronic properties. However, its poor environmental stability restricts its broad application. Here, a simple method for the fabrication of CsPbBr/TiO is investigated. The introduction of p-aminobenzoic acid, which has two functional groups, is critical for the capping of amorphous TiO on CsPbBr. After calcination at 300 °C, amorphous TiO crystallizes into the anatase phase. The CsPbBr/TiO NCs show high long-term stability in water and enhanced stability against ultraviolet radiation and heat treatment, owing to the chemical stability of TiO. More importantly, photo-electrochemical characterizations indicate that the formation of TiO shells can increase the charge separation efficiency. Hence, CsPbBr/TiO exhibits improved photoelectric activity owing to the electrical conductivity of the TiO in water. This study provides a new route for the fabrication of optoelectronic devices and photocatalysts based on perovskite NCs in the aqueous phase. Furthermore, the present results demonstrate that CsPbBr/TiO NCs has considerable potential to be used as a photoelectric material in optical sensing and monitoring.