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

Abstract

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).

Stability and photocurrent enhancement of photodetectors by using core/shell structured CsPbBr3/TiO2 quantum dots and 2D materials

“…Subsequently, a calcination process performed to dehydrate and remove the organic component at 400 °C, which was reported as the most suitable temperature for the calcination step without any decomposition of QDs. 13 …”

“…Subsequently, a calcination process performed to dehydrate and remove the organic component at 400 °C, which was reported as the most suitable temperature for the calcination step without any decomposition of QDs. 13 Fig. 2(b)-(d) illustrate CsPbBr 3 QDs, and QDs aer the hydrolysis process and calcination process in toluene, respectively.…”

“…PL quenching occurred aer the coating of TiO 2 because the excited electrons from the conduction band of QDs under the illumination of blue laser light transfer to the layer of TiO 2, which provides a new pathway for transferring electrons. 10,13 UV visible absorption spectra of the CsPbBr 3 QDs, CsPbBr 3 / TiO x and CsPbBr 3 /TiO 2 are shown in Fig. 2(l).…”

“…Furthermore, TiO 2 can protect QDs from degradation from external factors, which is crucial for developing optoelectronic devices. 13 …”

“…Furthermore, TiO 2 can protect QDs from degradation from external factors, which is crucial for developing optoelectronic devices. 13 In recent years, perovskite layer-based photodetectors (PDs) have received tremendous attention due to the perovskite's exceptional optoelectronic properties. Flexible photodetectors (FPDs), which form the core elements of exible optoelectronic systems, play vital roles in various areas such as modern industrial production, scientic research, medical diagnosis and military defense.…”