Tunable upconversion luminescence and optical temperature sensing based on non-thermal coupled levels of Lu3NbO7:Yb3+/Ho3+ phosphors

摘要： The color-tunable upconversion (UC) emission and optical temperature sensing based on non-thermal coupled levels (NTCL) were observed from the Yb3t/Ho3t codoped Lu3NbO7 phosphors synthesized by the solid-state method. The phosphors are capable of generating color tunable UC luminescence from green (yellow) to yellow (green) with the increase of the Yb3t concentration. The tunable emission is due to the different energy back transfer processes from Ho3t to Yb3t. The temperature sensing performances are investigated in the temperature range of 293–573 K based on NTCL by using fluorescence intensity ratio technology. The maximum absolute sensitivities are 0.37%K?1, 0.94%K?1, 0.27%K?1 at 298 K, which are based on three pairs NTCL of (5F4/5S2→5I8)/(5F5→5I8), (5F5→5I8)/(5F4/5S2→5I7) and (5F4/5S2→5I8)/(5F4/5S2→5I7) of Ho3t, respectively. The above results suggest that the as-prepared Lu3NbO7:Yb3t/Ho3t phosphors have great potential for the application prospects of upconverter, color tunable device and optical temperature sensor.