Dy3+/Pr3+ co-doped YVO4 white phosphor: Luminescence properties and highly sensitive optical thermometry

A novel dual luminescence centers thermometric strategy is proposed, by choosing intervalence charge transfer (IVCT) interfered Pr3+ emission as the temperature probe and lanthanide ion Dy3+ emission as the reference signal. Following this strategy, Dy3+/Pr3+ co-doped YVO4 phosphors were synthesized by a solid-state method and were characterized by XRD, SEM and luminescent spectroscopy of down-conversion. Under 320 nm UV excitation, the emitting color of YVO4:Dy3+, Pr3+ is white (0.315, 0.317) and the color temperature is 6479 K, suggesting the sample can be a promising LED white phosphor. Based on the distinct temperature-dependent behaviors of Dy3+ and Pr3+, the fluorescence intensity ratio of Dy3+:4F9/2-6H15/2 to Pr3+:1D2-3H4 in the sample exhibits excellent thermometry performance. The maximum absolute and relative sensitivity are 3.167 K-1@383 K and 4.094% K−1@333 K, respectively, not only that, but the relative sensitivity is more than 3% K−1 in the temperature range of 303–383 K, which are much higher than those of the previously reported optical thermometric materials. Furthermore, YVO4:Dy3+, Pr3+ has a temperature resolution of less than 0.136 K, and the phosphor exhibits good repeatability and reversibility. This work provides a novel approach to the development of highly sensitive optical thermometric materials.