The luminescent properties of CaYBO 4:Ln(Ln=Eu 3+, Tb 3+) under UV–VUV range

Abstract

The luminescent properties of CaYBO 4:Ln(Ln=Eu 3+, Tb 3+) were investigated under ultraviolet (UV) and vacuum ultraviolet (VUV) region. The CT band of Eu 3+ at about 245 nm blue-shifted to 230 nm in VUV excitation spectrum; the band with the maximum at 183 nm was considered as the host lattice absorption. For the sample of CaYBO 4:0.08Tb 3+, the bands at about 235 and 263 nm were assigned to the f–d transitions of Tb 3+ and the CT band of Tb 3+ was calculated according to Jφrgensen's theory. Under UV and VUV excitation, the main emission of Eu 3+ corresponding to the 5D 0– 7F 2 transition located at about 610 nm and two intense emission of Tb 3+ from the 5D 4– 7F 5 transition had been observed at about 542 and 552 nm, respectively. With the incorporation of Gd 3+ into the host lattice of CaYBO 4, the luminescence of Tb 3+ was enhanced while that of Eu 3+ was decreased because of their different excitation mechanism.