Study On Er³⁺/Yb₃₊codoped YAG?Y₂O₃and Lu₂O₃ Single Crystal Upconversion Luminescence Thermometry

In recent years,the optical temperature sensors using rare earth ion doped materials have attracted lots of attentions,among which the up-conversion fluorescent material is one of the research hotspots.In this paper,the up-conversion and the related temperature characteristics of Er3+/Yb3+co-doped YAG,Y2O3,and Lu2O3 single crystal fibers have been studied.In this paper,the following five types of fluorescent up-conversion materials:I#Er3+(0.5%)/Yb3+(5%):YAG,2#Er3+(0.5%)/Yb3+(5%):Y2O3,3#Er3+(0.5%)/Yb3+(1%):Lu2O3,4#Er3+(0.5%)/Yb3+(3%):Lu2O3 and 5#Er3+(0.5%)/Yb3+(5%):Lu2O3 are prepared through the steps of powders mixing,sintering and laser heated pedestal growth method(LHPG).Under the 980 nm laser diode excitation,the up-conversion and temperature sensing characteristics of Er3+/Yb3+ions co-doped different host materials have been studied.And the up-conversion and temperature sensing characteristics of Er3+ ions doped with various concentrations of Yb3+ions have also been were investigated.The results are shown as follows:(1)In the visible range,under the excitation of a 980 nm laser diode,the Er3+ions will be excited to emit three main emission bands:the green emission band corresponding to the 2H1 1/2?4I15/2 transition and the 4S3/2?4I15/2 transition and the red emission band,corresponding to the 4F9/2?4I15,2 transition.(2)The 2H11/2 and 4S3/2 energy levels of Er3+ions are a pair of thermally coupled energy levels.At different temperatures,the population will be changed,resulting in the changes of the corresponding fluorescence intensity.Therefore,it is possible to use the fluorescence intensity ratio(FIR)technique to process the fluorescence intensity data at different temperatures to obtain a curve of FIR value as a function of temperature for thermometry.(3)The results obtained by using the peak processing method,the partial range integrated processing method,and the overall range integrated processing method show that,although the results of the peak processing and partial range integrated processing methods are not significantly varied from the overall range integrated method,the fitting curve obtained by the range integration and the peak processing method does not match the data points very well.Some data points will deviate far from the fitted curve.Above all,the overall range integrated processing method can effectively avoid the lack of the other two processing methods,and effectively reduce the errors in processing.(4)The concentration of Yb3+ions can affect the up-conversion fluorescence efficiency and fluorescence intensity of Er3+ions.The proposal concentration of Yb3+ions is 5%,and the corresponding concentration of Er3+ion is 0.5%.