Energy Levels of ${\hbox {Ce}}^{3+}$ in ${\hbox {Lu}}_{0.8}{\hbox {Sc}}_{0.2}{\hbox {BO}}_{3}$

Cerium doped lutetium scandium orthoborate Ce³⁺:Lu_0.8Sc_0.2BO₃ is a novel and promising inorganic scintillator. For the sake of better understanding its scintillation mechanism, several approaches were undertaken to locate the Ce³⁺ energy levels relative to the host. To estimate the energy position of Ce³⁺4f levels with respect to the valence band, X-ray photoelectron spectroscopy (XPS) was used. Furthermore, the photoluminescence decays as a function of temperature, a widely used technique, was utilized to find the relative positions of Ce³⁺5d levels to the conduction band. Finally, the Ce³⁺ energy levels in Lu_0.8Sc_0.2BO₃ host was constructed, meanwhile, the effectiveness of the XPS technique to estimate the energy position of Ce³⁺ 4f levels relative to the conduction band was evaluated.