Microstructure, luminescence and thermal stability properties of NaSrPO4:Tb3+ phosphors with various doping concentrations prepared using conventional solid-state sintering

This paper reports the microstructure, luminescence and thermal stability properties of the NaSr1-xPO4:xTb(3+) powders (x = 0.008, 0.01, 0.02, 0.04 and 0.06) via the conventional solid-state sintering at 1200 degrees C for 5 h. The X-ray diffraction result verifies all diffraction peaks are pure phase of NaSrPO4. The luminescence results show that the NasrPO(4):xTb(3+) powders mainly excited at 370 nm have a series of the emission-states, related to the typical 4f --> 4f intra-configuration forbidden transitions of Tb3+, and a major emission peak of around 546 nm. The concentration quenching of the NaSr1-xPO4:xTb(3+) phosphors is appeared at x = 0.02. The decay time values of the NaSr1-xPO4:xTb(3+) phosphors for the D-5(4) state of the Tb3+ are around 3.30 ms to 3.60 ms. It is also found the chromaticity coordinate of NaSrPO4:Tb3+ phosphor varies with the increase of the concentration of Tb3+ ions from blue to green. Moreover, the thermal stability of the NaSrPO4:xTb(3+) phosphors is slightly better than that of conventional YAG phosphors. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.