An ultra-high sensitivity optical thermometer based on NaYF₄:Yb³⁺, Nd³⁺ nanomaterials

In recent years, improving the sensitivity of optical thermometers has been a research hotspot. In this paper, an ultra-high sensitivity optical thermometer based on NaYF
4
:Yb,Nd nanomaterials is investigated. With increasing temperature, the infrared light intensity and visible light intensity exhibited opposite temperature dependence under 980 nm laser excitation. In the temperature range of 323-523K, based on the fluorescence intensity ratio (FIR) technique, the temperature dependence of the FIR between emission peaks is studied, and the relative ($\mathrm{S}_{\mathrm{A}}$) and absolute sensitivity ($\mathrm{S}_{\mathrm{R}}$) are obtained. It is found that the maximum SA reaches 92.78 $\mathrm{K}^{-1}$, and the maximum SR reaches 16.28 %$\mathrm{K}^{-1}$. These excellent properties make NaYF
4
:Yb
³⁺
, $\mathrm{Nd}^{3+}$ nanomaterials will be used in high-precision optical thermometers.