Reserch On Optical Temperature Sensing Properties Of Rare Earth Doped Nano Fluorescent Materials

With the development of nano-devices,to achieve nano-scale temperature detection has become a challenge.Compared with ordinary thermometers,optical temperature sensing is a method of temperature measurement by monitoring the change of luminous intensity of the fluorescent material with the change of temperature,which is beneficial to the non-contact temperature measurement of micro-circuits,nano devices and intracellular liquid.In this paper,nano-core-shell materials with high luminous efficiency,nano-granular materials and transparent nano-ceramic materials with high thermal stability are used as the detection materials by using the relationship between the fluorescence intensity ratio of the adjacent thermal coupling energy of rare earth ions and the temperature change function.The rare earth ions Er3+,Tm3+,Eu3+ and Dy3+ doped nanomaterials were designed as optical temperature sensors,and the mechanism of optical temperature sensing was explained.The main contents of this paper are as follows:1?In order to solve the problem of easy oxidation of nanofluoride materials and realize the optical temperature sensing technology at high temperature,Na YF4:Yb3+,Re3+@Na YF4@Si O2(Re = Er,Tm)three-layer nano-phosphors were designed.The photo-temperature sensing of Yb3+/Er3+and Yb3+/Tm3+ double-doped three-layer core-shell nano-phosphor materials was studied in the range of 298 K-623 K based on the up-conversion of Er3+ and Tm3+ ions at 980 nm excitation.The dependence of the emission intensity ratios of Er3+ and Tm3+ ions of adjacent energy levels on the temperature is studied.It is proved that the 2H11/2/4S3/2 energy levels of Er3+ and 3F2,3/3H4 energy levels of Tm3+ are two pairs of thermally coupled energy levels.According to the sensitivity definition,the maximum relative sensitivity values of the two materials were obtained respectively.The mechanism of optical temperature sensing based on the upconversion luminescence of Er3+ and Tm3+ under 980 nm excitation is proposed.This work provides a new application prospect for three-layer fluoride nanoparticle as optical temperature sensor for temperature measurement.2?The energy transfer from the vanadate group to the Eu3+ was investigated by the effective absorption of the vanadate group [VO4]3-in the ultraviolet region.Eu3+ doped Ca7V4O17 nanoparticles were synthesized by the solution combustion method assisted with the citric acid as surfactant agent.Size and shape modifications were achieved by changing molar ratios of Ca2+/Cit3-.Under the UV excitation,the optical temperature sensing properties of Eu3+ doped Ca7V4O17 nanoparticles were studied in the temperature range of 298 K-573 K based on Eu3+ ion downconversion.Based on the fluorescence intensity ratio technique,the dependence of the intensity ratio of Eu3+ ions of the adjacent emission band on the temperature is studied.It is proved that the thermal coupling energy of Eu3+ is 5D1 and 5D0.The mechanism of optical temperature sensing based on the energy transfer from V4O17 to Eu3+ under 316 nm excitation is proposed.According to the study of the material sensitivity,it is found that the sensitivity of Eu3+ doped Ca7V4O17 nanoparticles is better than that of other Eu3+ doped materials in the low temperature range.3?The high temperature stability of La F3 nanocrystals and the solid solubility between other rare earth ions are proposed to realize the optical temperature sensing of La F3 nanocrystals doped with rare earth ions at high temperature.Dy3+ single-doped and Eu3+-Dy3+ co-doped containing hexagonal phase La F3 nanocrystals transparent glass ceramics were fabricated by a melt-quenching and subsequent heating method.The single-doped and co-doped samples showed that the strongest excitation of the two samples was at 394 nm,while that of the single-doped sample was 352 nm.The optical temperature sensing properties of Dy3+ single-doped La F3 transparent glass ceramics were studied in the temperature range of 298 K-523 K based on Dy3+ ion downconversion under 352 nm excitation.Based on the fluorescence intensity ratio technique,the dependence of the emission intensity ratio of Dy3+ ions on the temperature was studied.It was proved that the thermal coupling energy of Dy3+ was 4I15/2 and 4F9/2.Through the study of the chromaticity coordinates of the sample,it was found that the color of the sample was adjusted from white to yellow with the increase of temperature,which was mainly due to the decrease of blue luminescence.Based on the energy transfer between Eu3+ and Dy3+,the optical temperature sensing properties of Dy3+ doped transparent glass ceramics were discussed.It was found that the incorporation of Eu3+ ions could improve the thermal stability of ceramic materials.4?The high lumious efficiency of alkaline earth metal fluoride materials and the high thermal stability of ceramic materials were proposed to realize the light and temperature sensing technology of rare earth ion doped alkaline earth fluoride ceramic materials.Dy3+ doped transparent glass ceramic materials containing Ba F2,Ca F2 and Sr F2 nanocrystals were successfully prepared by a melt-quenching method.The optical temperature sensing properties of Dy3+ doped three kinds of nanoceramic materials were studied in the temperature range of 298 K-623 K based on Dy3+ ion downconversion under 350 nm excitation.Ba F2: Dy3+ glass ceramics can effectively inhibit the high temperature thermal quenching by studying the thermal quenching rate of Dy3+ ions with the temperature change.Based on the fluorescence intensity ratio technique,the relationship between the intensity ratio of adjacent emission peaks of Dy3+ ions and temperature is studied.It is proved that the thermal coupling energy of Dy3+ is 4I15/2 and 4F9/2.A new fitting formula is proposed to modify the relationship between the fluorescence intensity ratio and the temperature.Finally,the dependence of temperature and relative sensitivity of the three materials was studied.It was found that the relative sensitivity of Sr F2: Dy3+ glass-ceramic was higher and more suitable as the material of optical temperature sensing device.5?The optical temperature sensing of Ba2 Er F7 transparent glass ceramics under 980 nm infrared excitation was proposed by using high doped concentration of Er3+ in transparent Ba2 Er F7 glass ceramics.Ba2 Er F7 transparent glass-ceramic materials were successfully prepared by a melt-quenching method.The optical temperature sensing properties of the samples were studied in the temperature range of 298 K-573 K based on the fluorescence intensity ratio technique.The results show that 2H11/2/4S3/2 and 4F9/2(1)/4F9/2(2)are two pairs of thermally coupled energy levels by studying the relationship between the fluorescence intensity ratio and the temperature of the adjacent emission peaks.In particular,the 4F9/2(1)and 4F9/2(2)levels were first found in the Ba2 Er F7 transparent nanostructured ceramic material.The relationship between the sensitivity and temperature of the sample was obtained by comparing the relative sensitivity of the optical temperature sensing based on two pairs of thermally coupled energy levels.Furthermore,the results show that Ba2 Er F7 transparent glass and ceramic materials can simultaneously achieve optical temperature measuremen at high temperature and low temperature.