Research On Optical Temperature Sensing Properties Of Rare-Earth Doped SrWO₄

Temperature is a very important physical parameter in the fields of scientific research,medical treatment and military.In recent years,rare earth doped materials have gradually become a research hotspot in the field of optical temperature sensing due to their advantages of non-contact measurement,wide measurement range,low cost,good stability and high sensitivity.In this paper,the optical temperature sensing properties of SrWO₄ as matrix,Tm³⁺/Yb³⁺,Nd³⁺/Yb³⁺,Ho³⁺/Yb³⁺and Sm³⁺doped rare earth materials are studied and analyzed.The main work is as follows:The optical temperature sensing properties of three up-conversion phosphors,SrWO₄:Tm³⁺/Yb³⁺、SrWO₄:Nd³⁺/Yb³⁺and SrWO₄:Ho³⁺/Yb³⁺,were investigated.Firstly,the samples were prepared by high temperature solid-state reaction method.Then under a 980 nm diode laser excitation,the up conversion emission spectra of the sample materials were measured at different temperatures.Finally,with the fluorescence intensity ratio technique and fluorescence color change,thermal sensing properties of the samples were investigated.The conclusions are as follows:The maximum thermal sensitivity of 0.00617 K^-1 at 323K of SrWO₄:Tm³⁺/Yb³⁺and0.02857 K^-11 at 453 K of SrWO₄:Nd³⁺/Yb³⁺were achieved.And with the increase of temperature,the fluorescence color of SrWO₄:Ho³⁺/Yb³⁺gradually changed from yellow to orange.The research result showed that SrWO₄:Tm³⁺/Yb³⁺phosphor has advantages at room temperature,SrWO₄:Nd³⁺/Yb³⁺phosphor has important application value in the field of high temperature sensing,and SrWO₄:Ho³⁺/Yb³⁺phosphor can be used for fluorescence calibration of temperature changes.The down conversion Sm³⁺codoped SrWO₄ phosphors for optical temperature sensing have been investigated.Under a 404 nm excitation,the down conversion emissions of SrWO₄:Sm³⁺at the 564nm(⁴G_5/2→⁶H_5/2),600nm(⁴G_5/2→⁶H_7/2)and647nm(⁴G_5/2→⁶H_9/2)were obtained,respectively.Then we analyzed the relationship between the ratios of different emission peak and temperature in the down conversion spectrum.The results show the maximum temperature sensitivity of0.016 K^-1 at 300K is achieved.The research result showed that SrWO₄:Sm³⁺has a good prospect of temperature measurement at room temperature.