Yb3+/Tb3+ co-doped GdPO4 transparent magnetic glass-ceramics for spectral conversion

Tb3+ and Yb3+ ions co-doped transparent phosphate glass-ceramics containing monoclinic GdPO4 nanocrystals were successfully synthesized using a conventional high temperature melting quenching method in air atmosphere. The structure and morphology properties were systematically analyzed by recording X-ray diffraction patterns and transmission electron microscopy images, which indicate the GdPO4 glass-ceramics was well formed. The luminescent properties of the GdPO4: Yb3+, Tb3+ were investigated based on excitation, emission spectra and decay curves. All samples exhibited the emission of Tb3+ ions from 5D4 → 7FJ (J = 6, 5, 4 and 3) and 5D3 → 7FJ (J = 6, 5 and 4) under irradiation with ultraviolet and near infrared light. Specially, strong green up-conversion emission of Tb3+ at 543 nm (5D4 → 7F5) is observed. And the decay curves illustrate more efficient UC process in GdPO4 glass-ceramics rather than precursor glass. Energy transfer from Gd3+ to Tb3+ as well as cooperative energy transfer from Yb3+ pair to Tb3+ gives a dual mode luminescence. Laser power dependence of up-conversion shows that two-photon process is responsible for the green emission as expected. Additionally, the paramagnetic property of this material was discussed. The hysteresis plot (M−H) analysis results at room temperature indicate their good paramagnetic property. Based on the above results, the block GdPO4 glass-ceramics have potentials to serve as multifunctional materials applied in laser field materials.