Photoelectrochemically Active and Environmentally Stable CsPbBr₃/TiO₂ Core/Shell Nanocrystals

Abstract

Inherent poor stability of perovskite nanocrystals (NCs) is the main impediment preventing broad applications of the materials. Here, TiO 2 shell coated CsPbBr 3 core/shell NCs are synthesized through the encapsulation of colloidal CsPbBr 3 NCs with titanium precursor, followed by calcination at 300 °C. The nearly monodispersed CsPbBr 3 /TiO 2 core/shell NCs show excellent water stability for at least three months with the size, structure, morphology, and optical properties remaining identical, which represent the most water-stable inorganic shell passivated perovskite NCs reported to date. In addition, TiO 2 shell coating can effectively suppress anion exchange and photodegradation, therefore dramatically improving the chemical stability and photostability of the core CsPbBr 3 NCs. More importantly, photoluminescence and (photo)electrochemical characterizations exhibit increased charge separation efficiency due to the electrical conductivity of the TiO 2 shell, hence leading to an improved photoelectric activity in water. This study opens new possibilities for optoelectronic and photocatalytic applications of perovskites-based NCs in aqueous phase.

Ultrathin, Core–Shell Structured SiO2 Coated Mn2+‐Doped Perovskite Quantum Dots for Bright White Light‐Emitting Diodes

“…Zheng and co‐workers prepared CsPbBr 3 @TiO 2 core–shell nanocrystals, which presented super stability for three months storage in water with identical optical features remained. Whereas the crystallization process of TiO 2 required high temperature assist (300 °C), which resulted the quenching of perovskite QDs . Except these above materials, encapsulating QDs with silica shell has been recognized as one fantastic approach to improve the stability for perovskite QDs, because silica as an optical transparent, chemical inert, and nontoxic material can prevent the core materials from the release of toxic ion as well as chemical degradation.…”

Highly Efficient and Water‐Stable Lead Halide Perovskite Quantum Dots Using Superhydrophobic Aerogel Inorganic Matrix for White Light‐Emitting Diodes

“…[11,12] Accordingly, PQDs exhibit much lower stability than conventional rare-earth-based phosphor materials. [30] Generally, the protective shells of PQDs are prepared using these inorganic materials by in situ synthesis. [30] Generally, the protective shells of PQDs are prepared using these inorganic materials by in situ synthesis.…”

Monochromatic LEDs based on perovskite quantum dots: Opportunities and challenges

“…However, encapsulation of perovskite NCs in different inorganic matrixes can be a powerful strategy to enhance the NC stability and the protection against the above‐mentioned conditions such as high temperatures or humidity. Various inorganic matrixes such as SiO 2 , TiO 2 , and alumina have been reported . The investigations of the thermal stability of the perovskite QDs in display applications are crucial for applying them in optoelectronic devices such as LEDs.…”

“…Various inorganic matrixes such as SiO 2 , TiO 2 , and alumina have been reported. [53][54][55] The investigations of the thermal stability of the perovskite QDs in display applications are crucial for applying them in optoelectronic devices such as LEDs. Until today, perovskite NCs could not be integrated in the commercialization of display technologies.…”