Study On The Temperature Sensing Performance Of Several Apatite Structure Luminescent Materials

The non-contact temperature measurement technology based on the fluorescence intensity ratio of rare earth ions can provide accurate measurement in harsh environment,with fast response speed,higher accuracy and accuracy than other radiation temperature measurement technologies.Therefore,it is of great significance in temperature measurement.At the same time,excellent thermal stability and physical and chemical stability are provided by apatite structure luminescent materials,so it has great application potential in solid state lighting,industrial production and temperature sensing.Based on this,a series of apatite structure luminescent materials Ca₉Tb（PO₄）₅（Si O₄）F₂,which have potential application in the fluorescence intensity ratio temperature measurement,were synthesized by traditional high temperature solid phase method.The effects of structure regulation and trivalent cation doping on the luminescent performance and temperature sensing performance of the system luminescent materials were systematically studied.The main research results are as follows:（1）M_8.5Tb（PO₄）₅（Si O₄）F₂:0.5Mn²⁺（M=Ca,Sr,Ba）phosphors were prepared,and the effects of divalent cation substitution on the luminescence properties and temperature sensing properties of the system were studied.The results showed that Tb³⁺→Mn²⁺energy transfer occurred in the phosphors.With the increase of divalent cation radius,due to the increase of crystal plane spacing,the position of XRD diffraction peak of the samples shift to a lower angle and the emission peak of the phosphors shift to blue.Due to the increase of non-radiation relaxation rate,the fluorescence attenuation lifetime of the samples decreases gradually,and the color of the samples can be adjusted from yellow to green.In addition,due to the decrease of non-radiative transition,the energy transfer between Tb³⁺and Tb³⁺increases,so the overall luminescent thermal stability of the samples increases,and the maximum relative sensitivity of temperature sensing decrease significantly.（2）Ca_8.5Tb（PO₄）₅（Si O₄）_x（Ge O₄）_1-xF₂:0.5Mn²⁺（x=0,0.3,0.5,0.7,0.9,1）phosphors were prepared,and the effects of partial and complete substitution of[Ge O₄]^4-by complex anion[Si O₄]^4-on the luminescence and temperature sensing properties of the phosphors were studied.The results show that with the decrease of[Ge O₄]^4-doping concentration,the fluorescence decay lifetime of the phosphor decreases gradually,and the CIE coordinate of the sample can be adjusted from green to yellow,but the thermal stability of the sample does not change greatly.With the decrease of[Ge O₄]^4-complex anion group,the maximum relative sensitivity value of Ca_8.5Tb（PO₄）₅（Si O₄）_x（Ge O₄）_1-xF₂:0.5Mn²⁺phosphor increases gradually.（3）Ca₉Tb（PO₄）₅（Si O₄）F₂:x Tb³⁺,1-x Dy³⁺and Ca₉Tb（PO₄）₅（Si O₄）F₂:x Tb³⁺,1-x Sm³⁺（x=0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9）phosphors were successfully prepared,and the energy transfer mechanism of Dy³⁺→Tb³⁺and Tb³⁺→Sm³⁺was confirmed.By adjusting the doping amount of Tb³⁺and Dy³⁺or Tb³⁺and Sm³⁺ions,the phosphors can be changed from yellow-green to blue-green/blue.In addition,the lifetime of the phosphors increases gradually with the decrease of the concentration of Dy³⁺and Sm³⁺,because the sensitizer has an additional attenuation channel to shorten the lifetime of the excited state.Moreover,with the same doping amount of Dy³⁺and Sm³⁺,the fluorescence decay lifetime and maximum relative sensitivity of Dy³⁺doped phosphors are better than those of Sm³⁺doped phosphors.