Upconversion emission, cathodoluminescence and temperature sensing behaviors of Yb3+ ions sensitized NaY(WO4)2:Er3+ phosphors

A series of Yb3+ ions sensitized NaY(WO4)2:Er3+ phosphors were synthesized through a solid-sate reaction method. The X-ray diffraction (XRD), upconversion (UC) emission and cathodoluminescence (CL) measurments were applied to characterize the as-prepared samples. Under the excitation of 980 nm light, bright green UC emissions corresponding to (2H11/2,4S3/2)→4I15/2 transitions of Er3+ ions were observed and the UC emission intensities showed an upward trend with increasing the Yb3+ ion concentration, achieving its optimum value at 25 mol%. Furthermore, the temperature sensing behavior based on the thermally coupled levels (2H11/2,4S3/2) of Er3+ ions was analyzed by a fluorescence intensity ratio technique. It was found that the obtained samples can be operated in a wide temperature range of 133-773 K with a maximum sensitivity of approximately 0.0112 K−1 at 515 K. Ultimately, strong CL properties were observed in NaY(WO4)2:0.01Er3+/0.25Yb3+ phosphors and the CL emission intensity increased gradually with the increment of accelerating voltage and filament current.