Tb-doped YPO4 phosphors: Polyacrylamide gel synthesis and optical properties

摘要

Single phase of Tb-doped YPO4 phosphors with xenotime structure were successfully synthesized via a polyacrylamide gel at different annealing temperatures (650-1050 degrees C). The crystal structure, thermal behavior and optical properties of the as-synthesized samples were investigated by XRD, TG-DTA, FT-IR, PL, and XPS. The effects of heat treatment on the structure and luminescence properties of samples were discussed. The PL spectra results reveal that the annealing temperature plays a key role in the luminescence properties of products. The samples obtained under 650-850 degrees C exhibit a strong green emission at 546 nm, attributing to the D-5(4)-F-7(5) transition of Tb3+, while the samples produced above 850 degrees C emit dominating blue lines at 381 and 415 nm, corresponding to the D-5(3)-F-7(6) and D-5(3)-F-7(5) transitions, respectively. The XPS results imply that a part of doping Tb3+ ions may be oxidized to Tb4+ on the high-temperature thermal treatment process, which could be the reason for the bluish color of Tb-doped YPO4 phosphors. (C) 2016 Elsevier B.V. All rights reserved.