Luminescent properties and energy transfer behavior between Tm3+ and Dy3+ ions in co-doped phosphate glasses for white LEDs

In order to obtain white light-emitting materials, the luminescent glasses composed of SrO-ZnO-TiO2-P2O5 co-doped with Tm3+ and Dy3+ ions were synthesized by a conventional melting-quenching method. The luminescent properties of Tm3+ and Dy3+ in zinc strontium phosphate glasses were investigated, where the emission spectra show possible energy transfer mechanism between Tm3+ and Dy3+ ions. The energy transfer carries out via resonant transfer modes, which is easily understood from Tm3+ and Dy3+ energy level diagrams. The decreasing in mean-duration time of Tm3+:1D2 and Dy3+:4F9/2 obtained from the decay curves makes a further evidence of energy transfer from Tm3+ to Dy3+ ions and Dy3+ to Tm3+ ions in the glasses.