Abstract

Eu³⁺-activated calcium silicate (CaO–SiO₂∶Eu³⁺) luminescent films were prepared by the sol–gel method. The structural evolution of the film was studied by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the luminescence properties of the phosphor films were investigated as a function of heat treatment temperature. The XRD study indicates that a kilchoanite phase forms in the film sintered at 800 °C, which is different from that in gel powder treated under the same conditions. The SEM results show that the film thickness decreases and the particles in the film become smaller with increasing heat treatment temperature. The CaO–SiO₂∶Eu film shows the characteristic emission of Eu³⁺ under UV excitation, with the Eu³⁺⁵D₀ → ⁷F₂ band (616 nm) being the most prominent. A large difference in the Eu³⁺ lifetime is observed between the film samples treated at 500 and 700 °C (or above). Concentration quenching occurs when the Eu³⁺ doping concentration is above 6 mol% of Ca²⁺ in the film.