| As one of the most basic and important thermodynamic parameters,temperature plays an extremely important role in many fields,such as industrial production,aerospace,scientific research,and biomedicine.Therefore,accurate temperature measurement has always been a key research topic in scientific research.Optical temperature sensing technology has quickly become the most potential temperature measurement technology due to its non-contact,fast response,high precision and other advantages.At present,the research field of optical temperature sensing materials is facing two urgent problems.The first is that the temperature measurement range of the material is generally limited to the range of room temperature to 200?,and the luminescence material loses its temperature measurement performance due to temperature quenching at ultra-high temperatures.The second is that the temperature measurement sensitivity of the material is still not satisfactory,and it is difficult to meet the requirement of practical applications.In recent years,domestic and foreign many scientific and technological workers have tried various strategies to solve the above problems.Based on previous research,this thesis further researches and explores several new inorganic optical temperature sensing materials.The work not only develops several new temperature sensing materials with better performance,but also provides strategies and inspiration for exploring inorganic optical temperature sensing materials with excellent performance.This thesis comprehensively investigated the literature on optical temperature sensing materials in recent years,and summarized temperature sensing based on multiple parameters such as fluorescence intensity,fluorescence intensity ratio,fluorescence lifetime,fluorescence spectrum peak position,fluorescence spectrum bandwidth,and polarization anisotropy,and analyzed their principles,advantages and disadvantages.On this basis,a detailed classification and discussion of inorganic optical materials based on fluorescence intensity ratio to achieve temperature sensing are carried out.The temperature sensing performance of temperature sensing materials(absolute sensitivity,relative sensitivity,resolution,repeatability and temperature measurement range)and its influencing factors are summarized and summarized On the basis of previous studies,we further researched and explored new inorganic optical temperature sensing materials,and developed several excellent temperature sensing materials,which provided some ideas for exploring the strategies and methods of excellent inorganic optical temperature sensing materialsThe work of this thesis mainly includes the following four parts(1)Sr2MgA122O36:Cr3+ materials were synthesized by high temperature solid-phase reaction method.The narrow-band originated from 2E?4A2 transition and broadband originated from 4T2?4A2 transition emission of Cr3+ions in this material are studied,ald it is found that the two emi ssion have different temperature-dependence under the effect of thermal coupling.The potential of the two emission intensity ratios as a signal sensing temperature was investigated,indicating that the Sr2MgAl22O36:Cr3+materials have high sensitivity near physiological temperature.This work reports a new energy-level thermally coupled optical temperature sensing material based on a single transition ion Cr3+to achieve dual emission(corresponding to the second chapter of this thesis)(2)The Li5Zn8Al9Ge5O36:Mn2+materials were synthesized by the high-temperature solid-phase reaction method.The occupancy of Mn2+ in Li5Zn8Al9Ge5O36:Mn2+ Materials can be controlled by changing the synthesis atmosphere.Mn2+ ions occupy four-coordinate tetrahedral centers in Li5Zn8Al9Ge5O36:Mn2+ materials synthesized under N2 atmosphere,while Mn2+ ions occupy six-coordinate octahedral centers in Li5Zn8Al9Ge5P36:Mn2+ materials synthesized under O2 atmosphere.By adjusting the atmosphere to O2 deficient environment,Mn2+occupies two sites at the same time,and Li5Zn8Al9Ge5O36:Mn2+materials exhibit two different emissions of green light and near-infrared light.Taking advantage of the temperature dependence of Mn2+emission in different coordination environments,a non-thermally coupled fluorescence intensity ratio temperature sensing model was constructed to achieve ultra-high sensitivity temperature sensing.This work is the first to realize high-sensitivity temperature sensing based on the dual-occupancy of Mn2+ ions in one host,which provides new inspiration for the design of new temperature sensing materials(corresponding to Chapter 3 of this thesis)(3)La2Mo3O12:Yb3+,Pr3+materials were synthesized by the sol-sol method.This work not only studied the down-conversion temperature sensing performance of Pr3+ single activated La2Mo3O12 materials,but also studied the temperature sensing performance of the dual-switch Yb3+,Pr3*co-activatied La2Mo3O12 materials in the down-conversion and up-conversion modes.The study found that the La2MO3O12:Yb3+,Pr3+ materials show up-conversion fluorescence thermal enhancement phenomenon under the combined interaction of up-conversion and intermediate valence charge transfer.The La2Mo3O12:Yb3+,Pr3+materials show excellent temperature sensing performance under the up-conversion mode.This work not only confirms the effectiveness of the intermediate valence charge transfer strategy for improving the temperature measurement sensitivity of materials,but also provides new strategy for exploring temperature sensing materials with high sensitivity,muti-switch and wide temperature measurement range(corresponding to Chapter 4 of this thesis).(4)The negative thermal expansion materials RE2Mo3O12:Yb3+,Er3+(RE=Sc,Y)and the positive thermal expansion materials La2W3O12:Yb3+,Er3+/Ho3+were synthesized by high-temperature solid-phase secondary sintering method.The up-conversion fluorescence thermal enhancement phenomenon of negative thermal expansion materials is attributed to its negative thermal expansion properties based on analysis and proof,the integrated intensity of SC1.42Mo3O12:0.54Yb3+,0.04Er3+sample at 753 K is thermally enhanced to 74.5 times that at 303 K.The effect of the photothermal effect excited by 980 nm on the heating of the SC1.42Mo3O12:0.54Yb3+,0.04Er3+was studied.The temperature sensing performance of negative thermal expansion materials was investigated.This work devolops suitable temperature sensing materials for measuring high temperature,and also provides reference for exploring inorganic temperature sensing materials with high sensitivity,high precision and wide temperature measurement range(corresponding to Chapter 5 of this thesis). |
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