The white light emission properties of Tm3 +/Tb3 +/Sm3 + triply doped SrO–ZnO–P2O5 glass

Abstract

The phosphate parent glasses, the rare earth ion single and tri-doped phosphate glasses in the SrO–ZnO–P2O5 ternary system were prepared by conventional melting–quenching method. The structure and thermal stability of the parent glasses were investigated by Fourier transform infrared spectroscopy (FT-IR) and differential thermal analyzer (DTA). The results show that with the P/O molar ratio increasing, the relative intensity of 530cm−1 bond becomes weaker and the relative intensity of 1284cm−1 bond gets strengthened, and the values of the glass stability parameters (K2, KSP) decrease after a previous increase, and reach the maximum when the mole ratio of P/O is 0.333 (P2O5=50mol%). Blue, green and red light emissions are separately observed in the photoluminescence spectra of Tm3+, Tb3+ or Sm3+ single-doped phosphate glasses excited by 357nm. The combination of these three emissions allows white light emission via adjustment of dopants' concentration. It is confirmed that energy transfer from Tm3+ (Tb3+) to Sm3+ occurs, which is reasonably interpreted based on energy level diagrams and the analysis of the fluorescence lifetimes.