CsPbBr3 perovskite quantum dots by mesoporous silica encapsulated for enhancing water and thermal stability via high temperature solid state method

Abstract

All inorganic perovskite quantum dots (PQDs) have great application prospects in the lighting and display fields due to their excellent photoelectric properties. However, their instabilities in water and high temperature lead to photoluminescence (PL) quenching, and colloidal synthesis methods usually use a mass of organic solvents, limiting their practical application. Herein, we successfully synthesized mesoporous silica (m-SiO₂) and employed a confinement effect to successfully synthesize CsPbBr₃@m-SiO₂ powders using a simple high-temperature solid-phase synthesis method in an air atmosphere. When the m-SiO₂ content is 0.2 g, optimal green luminous intensity is achieved with a peak wavelength of 522 nm and a full width at half maximum (FWHM) of 23 nm. CsPbBr₃@m-SiO₂ powders have excellent thermal stability, the PL spectral shapes do not change and the PL intensity can maintain 88.1 % of the original level after 10 heating cycles (200 °C). In addition, CsPbBr₃@m-SiO₂ powders exhibit excellent water stability, which can still be well dispersed after 30 days exposure to water, and the PL strength remain basically unchanged. This study presents a novel approach for the advancement of stable perovskite luminescent materials.