Microstructure, luminescence and thermal stability properties of NaSrPO_4: Tb~(3+) phosphors with various doping concentrations prepared using conventional solid-state sintering

摘要

This paper reports the microstructure, luminescence and thermal stability properties of the NaSr_(1-x)PO_4:x Tb~(3+) powders (x = 0.008,0.01,0.02,0.04 and 0.06) via the conventional solid-state sintering at 1200 ℃ for 5 h. The X-ray diffraction result verifies all diffraction peaks are pure phase of NaSrPO_4. 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 Tb~(3+), and a major emission peak of around 546 nm. The concentration quenching of the NaSr_(1-x)PO_4:xTb~(3+) phosphors is appeared at x= 0.02. The decay time values of the NaSr_(1-x)PO_4:Tb~(3+) phosphors for the ~5D_4 state of the Tb~(3+) are around 3.30 ms to 3.60 ms. It is also found the chromaticity coordinate of NaSrPO_4:Tb~(3+) phosphor varies with the increase of the concentration of Tb3* ions from blue to green. Moreover, the thermal stability of the NaSrPO_4:xTb~(3+) phosphors is slightly better than that of conventional YAG phosphors.