The Study On Optical Temperature Sensing Performance Of Rare Earth Doped Gadolinium Aluminum Borate Phosphor

Optical temperature sensing technology has the advantages of high sensitivity and resolution,non-contact and non-invasive nature and so on.Therefore,it has been widely applied in industry,agriculture,medicine,etc.Rare earth ions-doped ratiometric optical thermometer is preferred by researchers as they can provide self-calibrated and sensitive measurement,and are independent of concentration,excitation source power fluctuation,emission loss,etc.However,the current study mainly focuses on single-mode temperature measurement,facing the problem of insufficient measurement accuracy.Therefore,it is an urgent need to exploit the dual-mode optical thermometer with temperature measurement performance mutually verified and complementary advantages.Herein,environment friendly and thermally stable rare earth gadolinium aluminum borate materials are selected as the matrix,and Dy³⁺and Eu³⁺co-doped ratiometric optical thermometer is constructed.On this basis,the energy transfer between rare earth ions is removed,and the luminescent intensity ratio-luminescent lifetime dual-mode optical temperature sensing is realized.By further replacing the luminescent center with metal ion,the sensitivity of luminescent lifetime temperature measurement in dual-mode optical temperature sensing is improved.This paper provides a reference for the development of new dual-mode optical temperature measurement technology.Specific research results are as follows:（1）Hexagonal phase Gd Al₃（BO₃）₄:Dy³⁺,Eu³⁺phosphors were prepared.Both Dy³⁺and Eu³⁺could be sensitized by Gd³⁺under 311 nm excitation,and Dy³⁺could transfer energy to Eu³⁺through dipole-quadrupole interaction.The optical temperature sensing with the highest sensitivity of 1.37%K^-1 was achieved by using the emission intensity ratio of Dy³⁺at 574 nm and Eu³⁺at 613 nm.（2）Hexagonal phase Gd Al₃（BO₃）₄:Dy³⁺phosphors were prepared.With the increase of temperature,the emission intensity of Dy³⁺increased at 452 nm and decreased at 482 nm,and the decay time of the strongest emission peak at 574 nm gradually became longer.The accurate and sensitive dual-mode optical temperature sensing was thus realized by using the luminescent intensity ratio of the thermal coupling levels and the luminescent lifetime of the strongest emission peak.（3）Hexagonal phase Ca₃Gd（Al O）₃（BO₃）₄:Bi³⁺,Eu³⁺phosphors were prepared by replacing Dy³⁺with Bi³⁺.The steady-state and transient spectra results showed that Bi³⁺can transfer energy to Eu³⁺by exchange interaction under 285 nm excitation,resulting in strong emission peaks at 388 nm and 622 nm,respectively.As the energy back transfer from Eu³⁺to Bi³⁺gradually dominated with the increasement of temperature,the thermal quenching effect of Bi³⁺at 388 nm was slightly weaker than that of Eu³⁺at 622 nm.By using the intensity ratio of the strongest emission peak of Eu³⁺at 622 nm and Bi³⁺at 388 nm as well as the luminescence lifetime of Bi³⁺at 388 nm,the dual-mode optical temperature sensing was realized.The measurement sensitivity with luminescence lifetime was improved by 11.4 times compared with the above work.