Preparation And Static Performance Study Of The Temperature Sensing Layer Of The Flexible Temperature Sensor Based On Fabri

With the development of flexible wearable and portable electronic devices,intelligent wearable products had become a part of people’s life.In recent years,flexible electronic devices had shown explosive growth,and a new generation of flexible wearable sensors had become the core of intelligent flexible electronic systems.But so far,most flexible temperature sensors used polymer as the substrate,which was difficult to meet the temperature measurement on the surface of high curvature objects.Based on this,in this paper,TPU coated polyester fabric was used as the substrate of flexible temperature sensor,silver paste was printed on the substrate by screen printing technology as the electrode,Ag nanoparticles were deposited on the substrate by magnetron sputtering technology,and finally a Zn O nano film was deposited on the temperature sensing layer as the isolation layer to isolate the water and oxygen in the air,prolonged the service life of the temperature sensing layer and enhanced the oxidation resistance of the film.Different temperature sensing layers of Ag film flexible temperature sensors were prepared by changing magnetron sputtering power,sputtering pressure and film thickness.A self-assembled flexible temperature sensor test platform was used to test the change of square resistance of the temperature sensing layers in the temperature range of 25-42℃.The TCR,linearity,hysteresis,drift and reliability of the Ag temperature sensing layers were calculated to evaluate the static characteristics of the Ag temperature sensing layers prepared under different sputtering conditions.Combined with XRD crystallization test and SEM surface morphology test of Ag layers,the factors affecting the static parameters of temperature sensing layers of Ag were further analyzed.The control variable method was used to explore the optimal preparation process of the flexible temperature sensor.The self-assembled flexible temperature sensor test platform was used to test the resistance of the Ag layers with the change of temperature,and the static parameters of the layers were calculated.The experimental results showed that when the sputtering power was 90W,the sputtering pressure was0.8Pa and the film thickness was 200nm,the optimal TCR of Ag layers was0.00234℃^-1.After the heat treatment at 160℃,the TCR was further improved to0.00262℃^-1.X-ray diffractometer,thermal field emission scanning electron microscope and energy dispersive spectrometer were used to analyze the structure and element content of the surface of Ag layers.It was found that under the same sputtering conditions,after low-temperature heat treatment,the crystallinity of the temperature sensing layer of Ag became better,the bonding between Ag particles became closer,the sensitivity to temperature increased,the conductivity and TCR increased.SEM test results showed that the better the flatness of the film,the larger the particles formed by Ag nanoparticles,the better the conductivity of the temperature sensing layer of Ag layer and the higher the TCR.EDS test results showed that the element contents of oxygen and nitrogen in the temperature sensing layer had not changed before and after heat treatment,and the temperature sensing layer has certain antioxidant capacity.The sensor temperature layer lays a foundation for the body temperature monitoring system of intelligent wearable products.