Optical properties of Eu3+-doped antimony-oxide-based low phonon disordered matrices

A new series of monolithic Eu2O3-doped high antimony oxide (40-80 mol%) content disordered matrices (glasses) of low phonon energy (about 600 cm(-1)) in the K2O-B2O3-Sb2O3 (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 Eu3+ 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 Eu2O3-doped glasses upon excitation at 393 nmradiation exhibit six emission bands in the range 500-750 nm due to their low phonon energy. Of these, the magnetic dipole D-5(0) -> F-7(1) transition shows small Stark splitting while the electric dipole D-5(0) -> F-7(2) transition undergoes remarkable Stark splitting into two components. They have been explained by the crystal field effect. The Judd-Ofelt parameters, Omega(t=2,4,6), were also evaluated and the change of Omega(t) with the glass composition was correlated with the asymmetric effect at Eu3+ ion sites and the fundamental properties like covalent character and optical basicity. We are the first to report the spectroscopic properties of the Eu3+ ion in KBS low phonon antimony glasses.