A novel green phosphor GdCaAlO4:Tb3+ for PDP application

A novel green-emitting nano-sized phosphor, Tb3+-doped GdCaAlO4 was synthesized with a precursor prepared by citrate sol-gel method at relatively low temperature. Powder X-ray diffraction (XRD) analysis confirmed the formation of GdCaAlO4. Field-emission scanning electron microscopy (FE-SEM) observation indicated a narrow size-distribution of about ∼100 nm for the particles with a spherical shape. Upon excitation with near UV and vacuum ultraviolet (VUV) light, the phosphor showed strong green-emission peaked at around 546 nm, corresponding to the 5D4→7F5 transition of Tb3+, and the highest photoluminescence (PL) intensity at 546 nm was found at a content of about 12 mol% Tb3+. As the Tb3+ concentration increases, the fast diffusion of energy among terbium ions toward traps or impurities resulting in a decrease of the lifetime. The optical properties study suggests that it is a potential candidate for plasma display panels (PDPs) application.