Preparation, structure and luminescent properties of P2O5-Gd2O3-Ga2O3-NaF-ZnO glasses co-doped with Tb3+and Sm3+

White light-emitting diodes have been intensively explored as a technique of green energy-conversion in recent decades. In this work, a unique Tb3+/Sm3+ co-doped P2O5-Gd2O3-Ga2O3-NaF-ZnO glass consisting of Q0, Q1 and Q2 units was successfully synthesized. The DSC curves demonstrated that the glass stability gradually deteriorated with the increase of Sm3+ contents. The emission spectra exhibited the energy transfer from Dy3+ to Tb3+ ions, and the energy transfer efficiency and probability grew monotonously with the increase of Sm3+ contents. With the help of temperature-dependent emission spectra, the glasses were validated to be thermally stable. The fluorescence curves and Inokuti-Hirayama model demonstrated that the dominant mechanism in the energy transfer process was electric dipole-quadrupole interaction. In addition. the white-light emission with suitable chromaticity coordinates and CCTs could be obtained by adjusting the contents of the sensitizer and activator for PGGNZ glasses. All investigations revealed the potential application of Tb3+/Sm3+ co-doped glasses in optical device applications.