Synthesis, enhanced photoluminescence, and multifunctional applications of CaSr2(VO4)2:Sm3+ phosphor via co-doping with alkali metal (Li+, Na+, K+) ions

In this work, CaSr2(VO4)(2) phosphors singly doped with Sm3+ ions and co-doped with alkali metal (Li+, Na+, and K+) are prepared by using the high temperature solid state reaction. The X-ray diffraction (XRD) patterns exhibit that all the samples belong to the rhombohedral CaSr2(VO4)(2) phase with a space group of R3c (161). Upon excitation with the near-ultraviolet (UV) light, the characteristic Sm3+ emission lines, with the peak dominated at 605 nm, are achieved. Importantly, the photoluminescence (PL) intensity of Sm3+ ions can be enhanced significantly by co-doping with Li+, Na+, and K+ ions, and the reason can be attributed to the charge -compensated role of the alkali metal ions. Furthermore, the temperature-dependent PL experiments measured in the range of 298-573 K show that the optimal phosphor feature excellent stability against heat, making it suitable for acting as a UV-excited orange-red component for phosphor-converted wLEDs (pc-wLEDs). Besides, the PL intensity change of Sm3+ between F-4(3/2) -> H- 6(5/2) (531 nm) and (4)G(5/2) -> H- 6(5/2) (562 nm), F-4(3/2) -> H- 6(5/2) (531 nm) and( 4)G(5/2) -> H-6(7/2) (605 nm), and F-4(3/2) -> H-6(5/2) (531 nm) and (4)G(5/2) -> H-6(9/2) (645 nm) is also analyzed further in the temperature range from 298 K to 973 K, and the results show that the obtained phosphors are suitable for applying in thermometry. Obviously, we reveal multifunctional applications of the obtained phosphors for UV-excited pc-wLEDs and thermometry.

Automated summary

In this work, CaSr2(VO4)(2) phosphors singly doped with Sm3+ ions and co-doped with alkali metal ions (Li+, Na+, and K+) were prepared by high temperature solid state reaction. The study showed that co-doping with alkali metal ions significantly enhanced the photoluminescence intensity of Sm3+ ions. Moreover, the phosphors exhibited excellent stability against heat and were suitable for temperature measurement, making them ideal for UV-excited pc-wLEDs and thermometry.