Design of white-emitting optical temperature sensor based on energy transfer in a Bi 3+ , Eu 3+ and Tb 3+ doped YBO 3 crystal

Phosphors for remote optical determination have gained great attention for their promising applications, due to their advantageous rapid and noninvasive detection compared to traditional thermometers. In this work, a novel white-emitting optical temperature sensor based on energy transfer in a Bi 3+ , Eu 3+ and Tb 3+ doped YBO 3 crystal was designed. By making full use of the crystal structure information and an energy transfer strategy, we obtained a series of wide range color tunable phosphors including one with white emission, which makes it a candidate to replace phosphors for white light emitting diodes (WLEDs). The temperature sensitive energy transfer from the host and Bi 3+ to Eu 3+ and Tb 3+ has been demonstrated by analyzing the spectra from phosphors with different concentrations of the doping ions, in which Bi 3+ acts as both the emission center and sensitizer. By investigating the temperature-dependent emission of the white light emitting phosphor YBO 3 :0.04Bi 3+ ,0.003Eu 3+ ,0.008Tb 3+ , the absolute sensitivity value ( S a ) and relative sensitivity value ( S r ) were calculated in different temperature ranges of 200 to 300 K and 298 to 473 K, in which the maximum value of S r reaches 0.57% K −1 at 398 K. Although the S r values are not high enough for practical application, our design concept may provide a new perspective for developing novel multifunctional phosphors used as optical temperature sensors and WLED phosphors.