Growth and Temperature-Dependent Spectral Properties of Yb3+, Tm3+ Co-Doped NaY(MoO4)2 Crystal

The NaY(MoO4)(2):Yb3+/Tm3+ single crystal was grown by the vertical Bridgman method using spontaneous crystallization. After annealing at 850 degrees C for 24 h in a muffle furnace under an air atmosphere, the obtained light black crystal became transparent and optically clear. Powder X-ray diffraction (PXRD) confirmed that the as-grown crystal had the structure of scheelite. The segregation coefficients of Tm3+ and Yb3+ were 0.589 and 0.588, respectively. Under 980 nm excitation, the temperature dependence of the emission intensity of the crystal in the temperature range of 298-473 K was measured. The results show that, because of the thermal quenching effect, the emission intensity decreases as the temperature rises. The possible energy transfer modes between Yb3+ and Tm3+ ions were analyzed. The emission cross section was calculated to be 1.97 x 10(-2)0 cm(2) by the Fuchtabauer-Ladeburg formula, and the fluorescence lifetime was fitted to be 166.67 mu s.