Optical and luminescence properties of Eu3+-doped phosphate based glasses

Phosphate based glasses with chemical compositions of P2O5 + K2O+Al2O3 + CaF2 + Eu2O3 were prepared and characterized by the SEM with EDS, X-ray diffraction (XRD), differential thermal analysis (DTA), Fourier transform infrared (FTIR), Raman, absorption, emission, excitation and decay measurements at room temperature. An intense red emission at 614 nm has been observed corresponding to the D-5(0)-> F-7(2) transition of Eu3+ ions. Phonon side band (PSB) spectroscopic technique has been used to investigate the local structure around Eu3+ ions and phonon energy of the host. Judd-Ofelt parameters have been evaluated from the emission intensity ratios of D-5(0)-> F-7(J)/D-5(0)-> F-7(1) (J = 2, 4) transitions as well as from the absorption data under different constraints. The evaluated JO intensity parameters have been used to predict the radiative properties for the D-5(0)-> F-7(J) (J = 0-4) transitions. The experimental decay times (tau(exp)) of the D-5(0) level obtained by monitoring the emission at 614 nm are found to be independent of Eu3+ ions concentration.