Synthesis and Photoluminescence of CaLnAl[sub 3]O[sub 7]:Tb[sup 3+](Ln=La, Gd) in Ultraviolet to Vacuum Ultraviolet Range

Abstract

Single-phase of CaLn1-x Al3 O7: x Tb3+ (Ln=La, Gd, 0x1) was synthesized by citric-gel processing and photoluminescence (PL) properties in the range of 125-300 nm were investigated. The bands below 200 nm with maxima at approximately 180 nm in excitation spectra were assigned to the host lattice absorption, the bands above 200 nm with a maximum at about 235 and 237 nm in CaLa1-x Al3 O7: x Tb3+ and CaGd1-x Al3 O7: x Tb3+, respectively, corresponding to 4 f8 →4 f7 5 d1 transition of Tb3+. The phosphors exhibited a strong emission at around 543 nm under 147 and 254 nm excitation corresponding to the D45 → F57 transition of Tb3+. Optimal emission intensity was obtained at x=0.8 under 254 nm excitation and at x=0.2 under 147 nm excitation in CaLn1-x Al3 O7: x Tb3+ (Ln=La, Gd). The calculated luminescent chromaticity coordinates were (0.340, 0.559) and (0.337, 0.523) in Ca (Tb0.2 La0.8) Al3 O7 and Ca (Tb0.2 Gd0.8) Al3 O7 under 147 nm excitation. © 2006 The Electrochemical Society. All rights reserved.