Preparation And Applications Of Temperature Sensors Based On Aryl Diphosphate Oxides And Difluoroboron β-diketonate Derivative

Temperature is one of the most basic physical parameters in daily life and scientific research.The development of temperature sensor has attracted increasing attentions.Compared with the traditional contact thermometers,the fluorescent temperature sensors exhibit the advantages of self-reference,high spatial resolution,convenience,fast response and remote measurement.Organic fluorescent temperature sensors are favorable due to potentials in large area and flexible applications,good biocompatibility,and real-time measurement.Organic thin film temperature sensors provide a reliable and feasible method for displaying reversible temperature change or irreversible thermal history on large area or irregular surfaces.However,at present,the main bottleneck is the lack of organic materials for high temperature sensing or indication.This is because most organic fluorescent dyes face the problem of significant emission quenching caused by thermal deactivation.Firstly,this paper introduces the development of temperature sensors,including the types of fluorescent thermosensors,comparison between the national and international research development and especially high temperature ratiometic sensors.Then,we designed and prepared a ratiometic luminescence temperature sensor based on heat-resistant material of aryl diphosphate oxide,and studied the temperature sensing performance of the thermosensor.On the other hand,a series of high-performance film high temperature threshold temperature sensors based on thermochromic material of a difluoroboronβ-diketonate derivative with three naked-eye output signals have been developed.The excellent threshold temperature detection performance and applications of these temperature indicators are explored.In the first work,the ratiometric luminescent temperature sensor designed in this paper is based on the aggregation/disaggregation mechanism of high temperature resistant organic material aryl diphosphate oxide（DPO）.The compound exhibits dual emissions from both monomer and excimer.The ratio of the two luminescence can be affected by adjusting the temperature,and then the temperature sensing based on this ratio luminescence can be realized.The compound can be used as either a liquid temperature sensor or a solid film temperature sensor.Among them,in phosphoric acid buffer solution（PBS）,the ratio liquid temperature sensor is applied to the detection range from 20℃to 90℃,with the relative sensitivity as high as 2.22%℃^-1（50℃）.The relative error is less than 0.8%,and the temperature resolution is below 0.4℃.This indicates good potentials in biological microenvironment thermometers.In the solid film temperature sensor using polymer matrix of polymethylmethacrylate（PMMA）,a wide temperature sensing range（28-300℃）has been demonstrated,with the relative sensitivity of 2.01%℃^-1（at 178℃）and temperature resolution less than 0.3℃.The relative error is less than 2%in the high temperature range of 100-300℃.All these results show excellent sensing performance of this film temperature sensor.In another work,a series of sensitive high temperature threshold temperature sensors have been developed based on organic thermochromic dye of a difluoroboronβ-diketonate derivative（PR）.The temperature indication of these thermal sensitive films is based on three clear and high contrast naked-eye output signals,namely thermochromism,fluorescence discoloration and changes in luminous intensity.This is beneficial for portable temperature indication.Among them,in the PC film,the maximum sensitivity related to the emission wavelength shift,the variation of luminescence ratio and fluorescence intensity change can reach 4.64 nm℃^-1,441%℃^-1and 4.53%℃^-1 respectively.To the best of our knowledge,it is best film threshold thermometer reported so far.Using polymer matrixes of polystyrene（PS）,polymethylmethacrylate（PMMA）and polycarbonate（PC）with different glass transition temperatures,the threshold indicated temperatures are well tunable in the temperature range of 140℃to 180℃.Moreover,these threshold sensing films have excellent air stability,light stability and waterproof characteristics.This shows great potential in robust and outdoor threshold temperature indication and information storage.Finally,we summarize the research results of this paper,which reflects the excellent performance of organic luminescent temperature sensors and threshold thermosensors in the high temperature region,and outlook possible advances of these high-performance temperature sensors.