Ce3+luminescent centers of different symmetries in KMgF3single crystals

Abstract

Absorption, emission, and excitation spectra of KMgF${}_3$ doped with Ce${}^{3+}$ have been measured in the near ultraviolet up to 180 nm. In this fluoroperovskite lattice, absorption of the Ce${}^{3+}$ impurity is found at energies higher than 4.4 eV. Broad-band emissions are measured at 350 nm and 275 nm which are identified as the $5d\to 4f$ radiative recombination at two different Ce${}^{3+}$ centers. The same substitutional site is proposed for both centers, with the unperturbed site rapidly saturating with an increasing concentration of Ce${}^{3+}$ in favor of a site perturbed by two K${}^{+}$-ion vacancies.