Luminescent Properties of Eu ³⁺ ‐Doped BaLn ₂ ZnO ₅ (Ln=La, Gd, and Y) Phosphors by the Sol–Gel Method

Abstract

Three series of Eu 3+ ‐doped BaLn 2− x Eu x ZnO 5 (Ln=Y, Gd, and La) phosphor powders were prepared by the sol–gel process. Parameters that affect the photoluminescence (PL) intensity of phosphors were investigated in detail. The phase formation and identification of samples were characterized by thermogravimetry and differential thermal analysis and X‐ray diffraction (XRD), respectively. The morphologies of the phosphor particles and the spectra of the as‐prepared phosphors were investigated by means of field‐emission scanning electron microscopy (FE‐SEM) and PL measurements. The XRD results reveal that the sample adopts a tetragonal structure for BaLa 2− x Eu x ZnO 5 and the other two samples adopt an orthorhombic structure in our experimental ranges, and the formation temperature of the pure phase increases with the decreasing of the radius of Ln 3+ ions. The FE‐SEM images indicate that the size and the shape of phosphor particles are regular. The PL spectra of phosphors BaLn 2− x Eu x ZnO 5 (Ln=Y, Gd, and La) show the characteristic emissions of Eu 3+ . And the emission color of phosphors BaLn 2− x Eu x ZnO 5 (Ln=Y, Gd) could be tuned from white to red by changing the concentration of Eu 3+ , but the BaLa 2− x Eu x ZnO 5 only shows red emission and was independent to the concentration of Eu 3+ .