The luminescent properties of CaYBO4:Ln(Ln=Eu3+, Tb3+) under UV-VUV range

The luminescent properties of CaYBO4:Ln(Ln=Eu3+, Tb3+) were investigated under ultraviolet (UV) and vacuum ultraviolet (VUV) region. The CT band of Eu3+ 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 CaYBO4:0.08Tb3+, the bands at about 235 and 263 nm were assigned to the f-d transitions of Tb3+ and the CT band of Tb3+ was calculated according to Jφrgensen's theory. Under UV and VUV excitation, the main emission of Eu3+ corresponding to the 5D0-7F2 transition located at about 610 nm and two intense emission of Tb3+ from the 5D4-7F5 transition had been observed at about 542 and 552 nm, respectively. With the incorporation of Gd3+ into the host lattice of CaYBO4, the luminescence of Tb3+ was enhanced while that of Eu3+ was decreased because of their different excitation mechanism.