4f–5d Excitation Energy of Tb3+ in Solids

Abstract

Excitation spectra of the ${}^5{D}_4{\mathrm{\hspace{0.17em}\to \hspace{0.17em}}}^{7}F$ emission of Tb³⁺ were measured in Sc(or In) BO₃, and Y (or Gd) BO₃, Y₃Ga₅O₁₂, Sc (or Y) PO₄, and Sc₂ (or Y₂) O₃ at room temperature. The $\text{4f–5d}$ excitation band is discriminated from the host lattice excitation band by inspecting the concentration dependences of the excitation spectra. The energy and the shape of the $\text{4f–5d}$ excitation band are almost the same in the lattices with the same structure. The band splittings are related to the symmetry of the crystalline field acting on Tb³⁺. The $\text{4f–5d}$ excitation band is extremely enhanced by lowering temperature to 77°K.