Study On Spectral Regulate And Control And Fluorescence Temperature Sensing Performance Of Multi-location Eu²⁺ Ion Luminescent Phosphors

In this paper,Eu²⁺activated single host multi-location phosphors were prepared by high temperature solid-phase method in reducing atmosphere.The effects of doping concentration and temperature on the spectral regulation of fluorescent materials were studied.Due to the different response of two different luminescent centers to the temperature change,the fluorescence temperature sensing performance and its potential application value in the field of optical temperature sensing such as fluorescence probe are studied.The phosphor Sr₄Al₁₄O₂₅ activated by Eu²⁺was prepared.The effects of Eu²⁺concentration on the photoluminescence,excitation spectrum,diffuse reflection spectrum and fluorescence lifetime attenuation of Sr₄Al₁₄O₂₅ phosphors were studied.Under the excitation of 290nm,the 4f⁷→4f⁶5d¹ energy conversion behavior of Eu²⁺between 400nm and 490nm emission was confirmed.The fluorescence temperature was measured in the temperature range of 293-423K.It is observed that the thermal quenching behavior of two Eu²⁺emission centers were different.The fluorescence intensity ratio（FIR）curves of I₄₉₀ and I₄₀₀ in the phosphor showed obvious temperature dependence.At 373K,the maximum absolute sensitivity and relative sensitivity are 0.004K^-1 and 0.624%K^-1,respectively.Eu²⁺activated Ba₃Gd Na（PO₄）₃F phosphor was prepared.Under the excitation of365nm,its emission spectrum has two distinguishable luminescence bands in the blue and red region,which is caused by the characteristic emission of Eu²⁺4f⁷→4f⁶5d¹.Temperature-dependent luminescence experiments were performed,and the two light-emitting regions of the prepared phosphors respond differently to temperature changes.Using the FIR detection technology,the optimal absolute sensitivity and relative sensitivity of the material were obtained,which were 0.007K^-1（293K）and1.67%K^-1（293K）,respectively.Using fluorescence lifetime thermometry,the maximum values of S_a and S_r were 1.94K^-1（528K）and 1.63%K^-1（528K）,respectively.A series of Eu²⁺activated and N^3-substituted Li₄Sr Ca（Si O₄）₂ phosphors were prepared.Photoluminescence spectra and fluorescence decay curves were used to verify the dual sites of Eu²⁺in Li₄Sr Ca（Si O₄）₂ structure.The glow color of phosphor changed from blue to yellow with the increase of N^3-substitution concentration and temperature.Under the excitation of 363nm,the relationship between the luminescence intensity and decay lifetime of Eu²⁺in the range of 303K to 573K was studied systematically.As temperature rises,the color of the phosphor changes from the blue-violet light area to the yellow light area.According to the FIR detection technology,the maximum S_a of the material is 0.086K^-1（473K）,and the maximum of S_r is 3.18%K^-1（423K）.In addition,based on the fluorescence lifetime method,the maximum value of S_a is 1.47K^-1（363K）,and the maximum value of S_r is42.57%K^-1（573K）.In addition,through the substitution of N^3-,optical temperature measurement performance of Li₄Sr Ca（Si O₄）₂:Eu²⁺phosphor has been improved.