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

• Published in: Advanced functional materials Vol. 28; no. 1
• Main Authors: Li, Zhi‐Jun, Hofman, Elan, Li, Jian, Davis, Andrew Hunter, Tung, Chen‐Ho, Wu, Li‐Zhu, Zheng, Weiwei
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 04-01-2018
• Subjects: Anion exchanging; Charge efficiency; charge transport; Coating effects; core/shell nanoparticles; Electrical resistivity; functional coatings; Materials science; Nanocrystals; Optical properties; Optoelectronics; Perovskites; Photodegradation; Photoelectricity; Photoluminescence; Shell stability; Titanium dioxide; Titanium oxides; Water stability
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201704288

Inherent poor stability of perovskite nanocrystals (NCs) is the main impediment preventing broad applications of the materials. Here, TiO2 shell coated CsPbBr3 core/shell NCs are synthesized through the encapsulation of colloidal CsPbBr3 NCs with titanium precursor, followed by calcination at 300 °C. The nearly monodispersed CsPbBr3/TiO2 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, TiO2 shell coating can effectively suppress anion exchange and photodegradation, therefore dramatically improving the chemical stability and photostability of the core CsPbBr3 NCs. More importantly, photoluminescence and (photo)electrochemical characterizations exhibit increased charge separation efficiency due to the electrical conductivity of the TiO2 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.
TiO2 shell coated CsPbBr3 core/shell nanocrystals are successfully constructed, resulting in excellent water, photo and thermal stability. TiO2 shell coating effectively increases charge separation efficiency, hence leading to an improved photoelectric activity in water.