Study On Preparation,Optical And Temperature Sensing Properties Of Rare-earth Doped Phosphate Glass Ceramics

With the rapid development of information,energy and biomedicine,the requirements for temperature measurement is becoming more and more stringent.Traditional thermometers are not suitable for temperature measurement in micro or corrosive special environments owing to some limitations of their internal properties.Optical temperature measurement has attracted extensive attention due to its non-contact nature.The optical temperature measurement of rare-earth doped fluorescent materials is different from that of traditional thermometers,them has the advantages of non-contact,fast response time,anti-electromagnetic interference,high sensitivity as well as high spatial resolution.Therefore,temperature detection has a wide range of application prospects in biological cells,high-voltage circuits,wind tunnel models and microelectronic devices.Phosphate glass and glass-ceramics are good luminescent matrix materials,which have the advantages of high rare earth solubility,long luminescent life,moderate phonon energy and not easy concentration quenching.However,pure phosphate glass also has some disadvantages,such as slightly poor stability and thermal conductivity,but also has a certain degree of moisture absorption.Therefore,the further exploration of phosphate glass with excellent comprehensive properties is the research focus in this field.Part one,a series of Tb³⁺/Eu³⁺ doped transparent Na₂O–Ba O–P2O5–B2O3–Zr O2 glass samples were successfully fabricated with the high-temperature melt-quenching method and systematically studied the optical properties.Besides,the energy transfer process and efficiency values were given.The variable temperature spectrum is tested repeatedly with a temperature-raising instrument,and the dependence of fluorescence characteristics on temperature is discussed in detail by using two optical temperature-measuring mechanisms.On the one hand,based on the thermal quenching effect of Eu3+ ions,the dependence of fluorescence intensity on temperature was discussed.On the other hand,another scheme of optical thermometry was demonstrated,the self-reference temperature dependence of intensity ratio of Tb³⁺ versus Eu3+ owing to energy transfer from Tb³⁺ to Eu3+,the maximum value of relative sensitivity SR was about 1.25% K^-1 at 573 K.The results imply that Eu3+/Tb³⁺ doped phosphate glass may find potential applications as optical temperature sensing substance.Part two,transparent glass was successfully prepared by high-temperature melt-quenching method.The process and efficiency of energy transfer from Dy³⁺ to Tb³⁺ were studied and employed in optical temperature sensor.In this work,the temperature dependence of the luminescence properties was explored in detail with two different schemes.On the one hand,the temperature dependence of fluorescent intensity ratio of Tb³⁺?541nm?against Dy³⁺?574 nm?utilizing energy transfer from Dy³⁺ to Tb³⁺ and diverse thermal quenching actions of them.Firstly,the temperature dependence of fluorescent intensity ratio of thermal couple energy levels of Dy³⁺ ions were investigated.What is more,three heating-cooling cycle tests were carried out.Based on above work,a highly relative sensitivity was obtained to be 1.65% K^-1 at 298 K,the results indicate that our work may broaden the way of non-contact optical thermometry.The work shows that although the FIR temperature measurement technology has made great progress,but has been curbed,in order to breakthrough the bottleneck of sensitivity,a new temperature measuring mechanism was established,combining with the characteristics of the energy level structure of rare earth ions,using excitation temperature dependence of the weak of low excited states rather than the ground state to achieve high sensitivity and low thermal effect of the temperature detection.The specific work is as follows:Part three,novel transparent Na₂O–Ca O–P2O5–B2O3 glass ceramics?GC?containing apatite type Ca₈Eu₂?PO₄?₆O₂ nanocrystals were successfully fabricated via high-temperature melt-quenching technique with subsequent heat treatment.Firstly,GC samples with a size of about 12 nm in visible light band were obtained through comprehensive tests including DSC,XRD,TEM and transmission spectrum.Then the spectrometer was used to test the spectrum at room temperature to obtain excellent luminescence performance.Finally,Eu3+ low-level thermal occupation technology for optical temperature measurement was successfully explored by repeated experiments with a thermometer,and a high sensitivity of 1.79% K^-1 was obtained near room temperature,which is expected to be applied to optical fiber temperature sensor.