Multi-user equipment approved in grant: spectrofluorometer Edinburgh FS5

Abstract

Luminescent materials comprise a vast class of compounds, from photoluminescent, radioluminescent, cathodoluminescent materials, among others. In general, materials convert incident energy (Sunlight, ambient light, UV radiation, X-rays, etc.) into characteristic photon emission depending on the identity of the emitting ion. Luminescent materials are applied in high-performance solid-state devices, for example, phosphors for LEDs, radiation dosimeters, solar energy storage, photocatalysts, sensors and biological markers. In general, the materials most used for converting luminous energy are crystalline inorganic matrices originating from oxides (e.g. Y2O3), nitrides (e.g. AlN), oxynitrides (e.g. SrSiO2N2), sulfides (e.g. CaS), oxysulfides (e.g. Gd2O2S) and fluorides (e.g. NaYF4), doped with rare earth ions (RE: Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). Light emission from these materials can occur through various photophysical processes where the excitation and emission of the materials will largely depend on dopant rare earth ions. A special class of luminescent materials is the persistent luminescent materials (Persistent Luminescence - PeL). Such materials can store light energy for hours and even days in the form of charge carriers trapped in crystal defects. The stored energy can later be released in a controlled manner after absorption of available heat (kT) or light (hv). Because they have charge carrier storage properties through light irradiation, these materials can be called optical batteries. Optical batteries have diverse applications, including solid-state lighting, emergency lighting, optical markers, thermometry, bioimaging, photodynamic therapy and photocatalysis. In this project, PeL materials will be used as optical batteries to power photocatalytic processes in semiconductor photocatalysts (e.g. BiVO4/WO3). The selected materials will be obtained by microwave-assisted syntheses. The study of energy transfer and the mechanisms of the photophysical process will be studied using photoluminescence spectroscopy. (AU)