Preparation And Study Of Temperature Sensor Based On Phenothiazine Pyrene Triarylphosphoroxy Compounds

The change of temperature is closely related to our daily life,and people pay more and more attention to the research of temperature monitoring.Compared with traditional thermometers,organic fluorescent temperature sensors have unique advantages in flexibility,large-area,microenvironment and in-situ temperature measurement.Among them,the ratiometric fluorescent thermometer is based on the change of emission intensity ratio of two different wavelengths,which reduces the background interference and improves the sensitivity and accuracy through self calibration,so that it is a better temperature sensing method.However,most organic luminescence materials can not avoid luminescence quenching at high temperature and can not be applied to temperature detection in extreme environment.Based on this,we have carried out the following research:1、We have designed and prepared two phenothiazine pyrene triarylphosphoroxy compounds PZ1and PZ2 with high temperature resistance and ratio emission characteristics.After preliminary exploration,it is found that compound PZ1 has aggregation behavior in THF solution and PS film.2、Based on the dual effect of the temperature dependent change of molecular twist angle and thermal balance between local excited（LE）state and charge transfer（CT）state,both compounds can be used as liquid ratiometric temperature sensors with a wide thermo-detection range from-60℃to90℃.The maximum relative sensitivity（Sr）of PZ1/MOE solution is 1.033%K^-1 at 363 K（90℃）,the temperature resolution and relative error is less than 0.5 K and 1.8%in the range of 0-90℃,respectively.And the reversibility is excellent in the range of-60～70℃.The maximum Sr of PZ1 in buffer solution（PBS）was 3.35%K^-1（330 K/57℃）,the relative error is less than 4%and the temperature resolution is less than 1.2 K in a range of around 37.5 to 70℃.3、We prepared a series of high temperature threshold organic film indicators by synergetic effects of intramolecular local excited to charge transfer states and disaggregation from CT state aggregates to monomers when the temperature is higher than T_g of polymer matrix.In a single sample（the same polymer matrix PS）film,the multi threshold temperature sensing with luminescence color indication can be realized.Among them,PZ1/PS film can indicate three kinds of high temperature:120℃,140℃and 200℃,corresponding to blue white,sky blue and dark blue polychromatic emission respectively.In addition,PZ1/PS and PZ2/PS films can also achieve multi threshold and time-temperature dual indication,and they can display different colors at least four time points at120℃.In addition,by changing the polymer matrix with different T_g,the threshold temperature in different sensing system can be adjusted.These drop-casting organic themometer films indicate great potentials in robust and low-cost outdoor applications,as well as large area and flexible threshold temperature sensing.