Luminescence characterization and the energy level scheme for lanthanide doped CaYAl3O7

Spectroscopic studies of CaYAl3O7 doped with Ce3+, Tb3+, Eu3+ and Sm3+ were performed from visible to vacuum ultraviolet (VUV) at room temperature and showed the characteristic emission of the dopants. From the excitation curves,4f-5d transitions were identified for Ce3+ and Tb3+ and charge transfer processes were observed for Eu3+ and Sm3+. The experimental data were used to predict the energy levels of all divalent(Ln2+) and trivalent lanthanides (Ln3+) and to construct the host referred binding energy (HRBE) and vacuum referred binding energy (VRBE) schemes. The predicted values are in good agreement with experimental results which provide a better understanding of the CaYAl3O7 luminescent processes.