| Temperature is one of the most fundamental physical parameters in daily life and various natural sciences,and the development of temperature sensors is receiving increasing attention.Compared with traditional contact thermometers,the new fluorescent temperature sensor has advantages such as anti-interference,high spatial resolution,convenience,and non-contact remote measurement.Organic fluorescence temperature sensors can achieve large-scale,flexible,biological environment,and real-time temperature measurement performance.Organic thin film temperature sensors provide a reliable and feasible method for displaying reversible temperature changes or irreversible thermal history of large or irregular surfaces.However,the main obstacle currently lies in the lack of organic compounds for high-temperature sensing or indication,as most organic fluorescent dyes face significant emission quenching problems due to thermal deactivation.This article first introduces the development history of temperature sensors,discribes the various types of fluorescent temperature sensors,compares the current domestic and foreign research of temperature sensors,and emphasizes the importance of developing high-temperature ratiometric temperature sensors and threshold temperature sensors.Next,we designed and prepared a luminescent temperature sensor based on boron difluorideβ-diketone compound for ratio liquid temperature sensing and its performance was studied.In addition,we designed a high-performance solid film high-temperature temperature sensor with visible change of emission color,and explored the temperature detection performance and application value of this temperature indicator.The ratiometric luminescent temperature sensor designed in this article is based on the aggregation/depolymerization mechanism of boron difluorideβ-diketone compound（PXP,PZP）.The compound exhibits dual emission of monomers and excimers at appropriate concentrations.By adjusting temperature,the ratio of the two types of luminescence can be affected,thereby achieving temperature sensing of ratio luminescence.This compound can be used as both a liquid temperature sensor and a solid film temperature sensor.In MOE solution,the PXP ratio type liquid temperature sensor is applied in the detection range of 20℃to 90℃,with an absolute sensitivity of up to 0.3℃-1 and a relative sensitivity of up to 1.6%℃-1;Within the range of 20-90℃,the temperature resolution is less than 5K,and the relative error is less than 2.5%.At 90℃,the maximum absolute sensitivity of the MOE solution of PZP is 0.55℃-1,and the maximum relative sensitivity is 1.08%℃-1;Within the range of 20-90℃,the temperature resolution is less than 3.5K and the relative error is less than 3.3%.The temperature sensor designed in this article is based on PXP and PZP,which are doped in polymer matrix polystyrene（PS）and polymethyl methacrylate（PMMA）to prepare high-performance high-temperature sensing films visible to the naked eye.The temperature indication of these thermosensitive films can be based on changes in thermochromism,fluorescence discoloration,and luminescence intensity,which is beneficial for portable temperature indication.Among them,in PXP,its maximum absolute sensitivity（Sa）is 9℃-1（140℃）,and its maximum relative sensitivity（Sr）is 4%℃-1（180℃）.Meanwhile,taking PXP compounds as an example,within the temperature range of 20 to 220℃,the temperature resolution is less than 3.5 K,and the relative error is less than1%.In PZP,within the temperature range of 20 to 220℃,the temperature resolution is less than 3K,and the relative error is less than 1.9%.In addition,temperature indications that can be recognized by the naked eye based on rich changes in luminous colors.Finally,we summarize the research results of the paper,reflecting the excellent performance of the organic luminescent temperature sensors in the field of high-temperature sensing in this research work,and look forward to the development prospects of these organic luminescent temperature sensors. |
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