High performance silica micro-tube optical temperature sensor based on β-NaLuF4:Yb3+/Tm3+ nanocrystals

•β-NaLuF4:Yb3+/Tm3+ nanocrystals with a uniform morphology and hexagonal structure have been prepared by the solvothermal method.•SiO2 hollow capillary enhances the chemical and thermal stability of β-NaLuF4:Yb3+/Tm3+ nanocrystals.•The device can achieve higher sensitivity and accuracy as a high-temperature sensor.

Rare earth co-doped nanocrystals of β-NaLuF4: Yb3+/Tm3+ with a uniform morphology and hexagonal structure were synthesized by a solvothermal route. The structure of the synthesized material was investigated with X-ray diffraction, scanning electron microscope and transmission electron microscope techniques. The micro-tube structure including rare earth nanocrystals was achieved by drawing the SiO2 capillary under the flame. The fluorescence intensity ratio of non-thermal coupling levels of 1D2→3F4 and 1G4→3H6 were studied as a function of temperature around the range of 300-550 K. The maximum sensitivity was estimated to be 0.0047 K−1 at 525 K. These results indicated that the device may have great potential applications in optical temperature sensor.