Temperature is one of the basic physical quantities. Nowadays, emerging industries are developing rapidly, and it is difficult for existing commercial thermometers to meet the difficult and high-precision requirements of some special applications. Instead, optical temperature sensing solution based on luminescent materials has demonstrated unique advantages in temperature detection.

Luminous intensity ratio (LIR) temperature measurement technology is a very promising optical temperature measurement method. It is not affected by non-temperature factors, so the error is small. Combining LIR temperature measurement with UC can take advantage of both technology at the same time, particularly helpful in biomedical and autofluorescence environments.

In a study published in the Journal of Alloys and Compounds, Dr. WANG Qingran from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of Chinese Academy of Sciences (CAS) reports that Er³⁺/Yb³⁺ co-doped Gd₂Mo₄O₁₅ phosphor has potential application prospects in optical temperature measurement.

The researchers sunthesized the Gd₂Mo₄O₁₅: Er³⁺/Yb³⁺ system by using the solid-phase reaction method. X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectroscopy were used to study the phase, microstructure and morphology of the prepared samples. Compared with other kinds of oxides, under the excitationof 980 nm laser, the phosphor shows bright green UC luminescence, but red luminescence is very weak. This facilitates the application of luminescence temperature measurement based on the ²H_11/2 and ⁴S_³/2 energy levels of Er³⁺. 

Data shows that the weak red light emission is due to the high cut-off phonon energy of 960 cm^-1 and low emission efficiency of Gd₂Mo₄O₁₅. The above-mentioned phosphors are confirmed to have high absolute sensitivity and excellent heat resistance.

In addition, based on comparative studies of some familiar materials, it is suggested that the relative absorption rate of the transition from ⁴I_¹⁵/2 → ²H_11/2 to ⁴I_¹⁵/2 → ⁴S_³/2 can be used as a good measure of absolute sensitivity.

These important results show that Er³⁺/Yb³⁺ co-doped Gd₂Mo₄O₁₅ phosphor has potential application prospects in optical temperature measurement.

Contact:

Author: Dr. WANG Qingran

Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences

Changchun, Jilin 130033. China

E-mail: wangqingran20@mails.ucas.cn

Article links: https://doi.org/10.1016/j.jallcom.2021.162516