A simple, compact, low-cost, highly efficient thermometer based on green fluorescence of Er3 +/Yb3 +-codoped NaYF4 microcrystals

- A simple, compact, low-cost, highly efficient thermometer is developed.
- It is based on ratiometric fluorescence technique and Er/Yb:NaYF4 microcrystals.
- It consists of an LD, two lenses, one filter, one Si-photocell and one multimeter.
- The sensor shows good signal-to-noise ratio, and high resolution and sensitivity.
- The thermometer shows great potential for use in biological tissues and cells.

We developed a highly efficient optical thermometer based on intensity ratio of upconversion green fluorescence of Er3 +/Yb3 +-codoped NaYF4 microcrystals. The sensor consists simply of a 980 nm laser diode, one narrow-band interference filter, two lenses, one Si-photocell and one multimeter, while being without use of spectrometer and additional electronics. The device not only has a simple, compact structure (hence a low cost), but also displays highly efficient sensing performance, characterized by large signal-to-noise ratio due to strong fluorescence intensity, high thermal resolution and sensitivity, which have the values 1.3 K and 1.24 × 10− 2 K− 1, respectively, at the physiological temperature 310 K. The excellent sensing performance of the device was further confirmed by the results of the measurements repeated using a spectrometer. The thermometer is highly generalized that can be applied to other luminescent materials, and shows great potential for the physiological temperature sensing in biological tissues and cells.

We have developed a thermometer based on the ratiometric fluorescence technique and Er3 +/Yb3 +-codoped NaYF4 microcrystals. The device not only has a simple, compact structure (hence a low cost), but also displays highly efficient sensing performance, which is characterized by strong fluorescence intensity (hence large signal-to-noise ratio), and high thermal resolution (1.3 K) and relative sensitivity (1.24 × 10− 2 K− 1) at the physiological temperature 310 K. The excellent sensing performance of the device is confirmed by the results of the measurements by a spectrometer. The thermometer is highly generalized that can be applied to other luminescent materials, and shows great potential for the physiological temperature sensing in biological tissues and cells.426