Fluorescence temperature sensing based on thermal enhancement effect in negative thermal expansion matrix

Temperature sensor based on fluorescence intensity ratio has become the focus of temperature measurement because of its advantages of non-contact and fast response. However, optical thermometry materials still have some shortcomings such as low sensitivity and narrow temperature measuring range. In this work, Dy3+, Tm3+ singly doped or co-doped Sc2W3O12 phosphors were successfully synthesized. The luminescence of Sc2-xW3O12: xDy3+ phosphor shows abnormal thermal enhancement phenomenon. In situ X-ray diffraction and thermogravimetric analysis indicate that the fluorescence thermal enhancement is caused by the negative thermal expansion effect of the matrix. Blue light from Tm3+ and yellow light from Dy3+ were selected as detection signals, and the fluorescence intensity ratio was designed to detect the temperature more accurately. For this temperature sensing technology, the maximal absolute sensitivity is up to 0.0135 K−1 at 365 K, the maximal relative sensitivity is up to 0.71% K−1 at 375 K. The high sensitivities indicate that the titled phosphor has potential application value in the field of optical temperature sensing.