Influence of Annealing Temperature on Structural Properties and Stability of CsPbBr3/TiO2 Core/Shell

Although all-inorganic CsPbBr3 perovskites quantum dots exhibit an excellent photophysical properties, which could be applied in various applications, they still suffer from poor structural stability owing to environment factors. Therefore, TiO2 was coated on the CsPbBr3 QDs as a protecting shell to enhance their stability. Moreover, anatase phase of TiO2 shell was obtained by annealing at more than 300°C due to its most effective electron extraction properties among other crystalline forms of TiO2. However, the CsPbBr3 QDs can be degraded under high temperature. Herein, the annealing temperatures ranging from 300-500°C were optimized to obtain the anatase TiO2 shell and good crystallinity of CsPbBr3 QDs core. The morphology and optical properties of CsPbBr3 QDs, CsPbBr3/TiOx and CsPbBr3/TiO2 were studied by using transmission electron microscope (TEM), photoluminescence (PL) measurement and UV-Visible spectroscopy, respectively. Finally, the CsPbBr3/TiO2 annealed at the optimum temperature was compared with the bare CsPbBr3 QDs to prove the enhancement of their structural stability under ambient air by using X-ray diffraction (XRD).