Optical temperature sensing properties of Er3+/Yb3+ co-doped LuVO4 up-conversion phosphors

In this paper, Er3+/Yb3+ co-doped LuVO4 phosphors were synthesized by the hydrothermal method. The crystalline structure and up-conversion luminescence features have been investigated by X-ray diffraction (XRD), Raman spectroscopy and up-conversion emission spectra. Green emission located at 525 nm (H-2(11/2) -> I-4(15/2)) and 554 nm (S-4(3/2) -> I-4(15/2)), red emission centered at 655 nm (F-4(9/2) -> I-4(15/2)) have been observed excited by 980 nm laser. The up-conversion luminescence is enhanced significantly with the co-doping of Yb3+ ions due to the effective energy transfer from Yb3+ to Er3+ ions. Moreover, the optical temperature sensing property are recorded based on two thermally coupled levels (H-2(11/2) and S-4(3/2)) in the range of 100-500 K. By using the fluorescence intensity ratio method, the maximum value of absolute sensitivity (S-A) is obtained to be 0.0067 K-1 at 500 K. The results indicate that the LuVO4:Er3+/Yb3+ phosphors with high sensitivity could be applied as potential optical temperature-sensing materials.