Up-conversion and temperature sensing properties of Na2GdMg2(VO4)3:Yb3+, Er3+ phosphors

In this paper, Na2GdMg2(VO4)(3):Yb3+,Er3+ phosphors were synthesized through high-temperature solid-state method. According to X-ray powder diffractogram, diffuse reflection spectra, scanning electron microscopy, up-conversion (UC) emission spectra, power-dependent UC spectra, fluorescent lifetime curves, and temperature-dependent emission spectra, the crystal structures, UC luminescent characteristics, and the performances of temperature sensing by using fluorescence intensity ratio technique were studied in detail. Heavy-doped phosphors with 59% (Yb3+ and Er3+) doping content are achieved. In addition, excited by 980nm laser, three characteristic luminescence peaks of Er3+ at 525 nm (H-2(11/2) -> I-4(15/2)), 550 nm (S-4(3/2) -> I-4(15/2)) and 660 nm (F-4(9/2) -> I-4(15/2)) emerge in the UC spectra of Er3+ single-doped and Yb3+,Er3+ co-doped phosphors. UC spectra are dominated by green emission and greatly enhanced UC emission over 389 times is realized by introducing Yb3+. In addition, the ratiometric techniques of thermally coupled energy levels of Er3+ (525/550 nm, H-2(11/)/S-4(3/2) -> I-4(15/2)) are used to achieve a wide range of temperature measurement. When the temperature is 303 K, relative sensitivity is as high as 0.976%K-1. The minimal temperature resolution is 0.3 K@303 K. All experimental results show Yb3+,Er3+ co-doped Na2GdMg2(VO4)(3) phosphors might act as optical temperature sensing materials.

Automated summary

In this study, Na2GdMg2(VO4)(3):Yb3+,Er3+ phosphors were synthesized and their crystal structures, luminescent characteristics, and temperature sensing properties were investigated. The results suggest that these phosphors could potentially serve as optical temperature sensing materials.