The VUV–vis spectroscopic properties of phosphors Ca3Gd2(1−x)Ln2x(BO3)4 (Ln3+ = Ce, Sm, Eu, Tb)

The spectroscopic properties in VUV–vis range for phosphors calcium and gadolinium double borate Ca3Gd2(BO3)4 doped with rare-earth ions Ce3+, Sm3+, Eu3+ and Tb3+ were investigated. The host-related absorption, the f–d transitions of Ce3+ and Tb3+, as well as the charge transfer transitions of Sm3+ and Eu3+ in the host lattice are assigned and discussed. The CIE chromaticity coordinates for Eu3+- and Tb3+-activated phosphors are calculated.