NUV light-induced-visible emissions and dopant concentration-dependent optical thermometric behaviors in Y2Mo4O15:2xEr3+ phosphors

We reported the photoluminescence (PL) and optical thermometric properties of Er3+-doped Y2Mo4O15 phosphors synthesized by a facile sol-gel method. Upon the light excitation at a wavelength of 377 nm, all the compounds emitted visible green emissions with high color purity of 94.8%. A gradual enhancement in PL emission intensity was observed with increasing the Er3+ ion concentration in resultant compounds, reaching its optimal value when x = 0.04. The concentration quenching mechanism of Er3+ ions in the Y2Mo4O15 host lattice was dominated by the dipole-dipole interaction and the critical distance was estimated to be around 36.7 Å. With the aid of fluorescence intensity ratio technique based on the thermally coupled levels of Er3+ ions, the optical thermometric behaviors of the resultant phosphors were studied by analyzing the temperature-dependent PL emission spectra. It was found that the sensor sensitivities of the as-synthesized samples were sensitive to the Er3+ ion concentration. The maximum sensor sensitivity of the obtained phosphors reached up to 0.01 K−1 at 473 K when the doping concentration was 1 mol%. These observed results reveal that the Er3+-doped Y2Mo4O15 phosphors have promising applications in noninvasion optical thermometry.