Optical properties of Eu(3+)-doped antimony-oxide-based low phonon disordered matrices.

A new series of monolithic Eu(2)O(3)-doped high antimony oxide (40-80 mol%) content disordered matrices (glasses) of low phonon energy (about 600 cm(-1)) in the K(2)O-B(2)O(3)-Sb(2)O(3) (KBS) system was prepared by the melt-quench technique. Infrared reflection spectroscopy was used to establish the low phonon energy of the glasses. Amorphicity and devitrification of the glasses were confirmed by x-ray diffraction analysis. UV-vis absorption spectra of Eu(3+) have been measured and the band positions have been justified with quantitative calculation of the nephelauxetic parameter and covalent bonding characteristics of the host. These Eu(2)O(3)-doped glasses upon excitation at 393 nm radiation exhibit six emission bands in the range 500-750 nm due to their low phonon energy. Of these, the magnetic dipole (5)D(0) --> (7)F(1) transition shows small Stark splitting while the electric dipole (5)D(0) --> (7)D(2) transition undergoes remarkable Stark splitting into two components. They have been explained by the crystal field effect. The Judd-Ofelt parameters, Ω(t = 2,4,6), were also evaluated and the change of Ω(t) with the glass composition was correlated with the asymmetric effect at Eu(3+) ion sites and the fundamental properties like covalent character and optical basicity. We are the first to report the spectroscopic properties of the Eu(3+) ion in KBS low phonon antimony glasses.