Optical Temperature Measurement Design Of Rare Earth Doped Fluorescent Materials

By using the luminescence intensity ratio of adjacent thermal coupling energy levels of rare earth ions as a function of temperature,Er³⁺doped Ca₃Al₂O₆,Tm³⁺(Ho³⁺)doped Y₂O₃:Er³⁺,and Ca²⁺adjusted Er³⁺doped NaGdF₄ phosphor,Er³⁺doped NaYF₄ glass ceramic under dual-mode photoexcitation were designed for optical temperature measurement,and its application in the field of optical temperature measurement,it explores the effects of doping ion species,doping concentration,sample morphology,excitation power,excitation mode and host material on optical temperature measurement.The specific work of this paper is as follows:In the first chapter,the introduction introduces the optical temperature measurement background of rare earth doped fluorescent materials,the photoluminescence mechanism of rare earth doped phosphorescent materials,the optical temperature measurement mechanism.In the second chapter,this work presents a method to improve optical temperature detection of novel Ca₃Al₂O₆:Yb³⁺,Er³⁺as well as the control of excitation power.The fluorescence intensity ratio of the green emissions at 526 nm and 551 nm in Ca₃Al₂O₆:Yb³⁺,Er³⁺was studied as a function of temperature.By analyzing the temperature dependent upconversion spectra,total emission intensity,ratios of fluorescence intensity,and sensitivity,the effect of doping ions on the optical temperature detection of Ca₃Al₂O₆:Yb³⁺,Er³⁺is studied.The results show that the relative and absolute temperature sensitivity of Ca₃Al₂O₆:Yb³⁺,Er³⁺can be effectively enhanced by co-doping with Ba²⁺,Mg²⁺,Y³⁺,La³⁺,and Lu³⁺ions and controlling excitation powers.The temperature sensitivity of Ca₃Al₂O₆:6%Yb³⁺,0.6%Er³⁺,1.2%Mg²⁺can reach a maximum relative sensitivity of0.0078 K^-1 at 145 K.The third charpter presents a new method to improve the optical temperature behavior of Er³⁺doped Y₂O₃ microtubes by energy transfer and controlling excitation power.The influence of Tm³⁺(or Ho³⁺)ion and Er³⁺enenrgy transfer on optical temperature behavior of Y₂O₃:Er³⁺microtubes is investigated by analyzing the temperature and excitation power dependent emission spectra,thermal quenching ratios,fluorescence intensity ratios,and sensitivity.It is found that the thermal quenching of Y₂O₃:Er³⁺microtubes is inhibited by co-doping with Tm³⁺(or Ho³⁺)ion,moreover the maximum sensitivity value based on the thermal coupled ⁴S_3/2/²H_11/2 levels is enhanced greatly and shifts to the high temperature range,while the maximum sensitivity based on ⁴F_9/2?1?/⁴F_9/2?2?levels shifts to the low temperature range and greatly increases.The sensitivity values are dependent on the excitation power,and reach two maximum values of 0.0529/K at 24 K and 0.0057/K at 457 K for the Y₂O₃:1%Er³⁺,0.5%Ho³⁺at 121 mW/mm² excitation power.In the forth charpter,a method to adjust the optical temperature behavior by Ca²⁺doping to adjust the morphology of NaGdF₄:Er³⁺was presentsed.With the introduction of Ca²⁺,the phase changes from the GdF₃ to NaGdF₄ was achieved,and the shapes of NaGdF₄:2%Er³⁺were modified from irregular particles to pure hexagonal NaGdF₄ microtubes.An obvious enhancement of the total fluorescence intensity was observed after doping the Ca²⁺ion.The mixed GdF₃:2%Er³⁺and NaGdF₄:2%Er³⁺were not be quenched at the high temperature more than 473 K.A maximum relative sensitivity of 0.00213/K?416 K?was obtained at 20%Ca²⁺doping.In the fifth chapter,an effective method to adjust the optical temperature behavior of NaYF₄:Er³⁺through changing the up-conversion route under dual-mode excitation was presentsed.X-ray diffraction and transmission electron microscopy analyses show that NaYF₄:Er³⁺nanocrystalline are precipitated among the glass matrix.A synergistic enhancement effect between two infrared up-conversion processes is observed in NaYF₄:Er³⁺glass ceramics through controlling the dual wavelength?980 nm and 1545 nm?excitation source.The Er³⁺ions in metastable states excited by 980 nm photons are excited again by the 1545 nm photons.The 192.26%absolute enhancement of the 669 nm red emission is realized through the synergistic effect of infrared up-conversion induced by the 980 nm and 1545 nm dual-mode excitation,and it has excellent optical temperature measurement performance under single mode and dual mode excitation,which is suitable as an optical temperature measuring device.