Research On Wearable And Flexible Multifunctional Sensor Based On Patterned Graphene

Flexible electronic devices can be unaffected by deformations.As a 2D material,graphene has high electron mobility and excellent mechanical properties in the atmospheric environment.It can be used to make stretchable wearable devices.This paper mainly studies multi-functional flexible sensors based on graphene.The main research contents are as follows:(1)Graphene was grown on a germanium(110)substrate by chemical vapor deposition(CVD)and characterized by atomic force microscopy(AFM)and Raman spectroscopy.Results of characterization show that we have successfully prepared high-quality single-layer graphene.Based on graphene and graphene oxide materials,a flexible graphene humidity sensor was fabricated through patterning graphene,transfering graphene,growing metal,and spraying coating.The humidity response of the sensor was tested and its response mechanism was analyzed.Test results show that the sensor can respond to relative humidity,and its overall sensitivity reaches 0.57%/1%RH.Due to the different adsorption methods of water molecules,the flexible graphene humidity sensor can respond to different levels of humidity with two different mechanisms.(2)Based on graphene and reduced graphene oxide materials,flexible graphene temperature sensors were fabricated through patterning graphene,transfering graphene,growing metal,and spraying coating,and the temperature response of the sensors was tested.The test and analysis results show that the reduced graphene oxide exhibits a characteristic of decreasing resistance with increasing temperature,and the process is linear.After calculation,the sensitivity of the sensor to temperature reaches 0.31%/?.(3)Flexible graphene pressure sensor and flexible graphene proximity sensor were designed and fabricated.The flexible graphene pressure sensor was fabricated through patterning graphene,transfering graphene,growing metal and lamination processes,and the pressure response of the sensor is tested.The test results show that the capacitance of the sensor changes significantly under different pressures,and its sensitivity to pressure reaches 0.42%/k Pa.Similarly,we made a flexible graphene proximity sensor based on the edge effect of planar capacitors,and performed proximity measurement on the sensor.The test found that when an object approaches the sensor,the sensor capacitance drops sharply.The sensor was then optimized,and the performance is improved by about 5 times after optimization.(4)A flexible graphene multi-functional sensor was designed and fabricated.Through patterning graphene,transfering graphene,growing metal,and spraying graphene oxide or reduced graphene oxide,different flexible graphene sensors can be made relatively quickly,respectively as the upper and lower layers of the multi-function sensor.The two layers of sensors were laminated together at a 90-degree angle to obtain a flexible graphene multi-function sensor that can measure humidity,temperature,pressure,and proximity signals.Then,the corresponding test equipments were used to test the four signals respectively,and the selectivity of temperature,humidity and pressure of the multi-functional sensor were tested.The test results show that each function of the sensor is normal and the function selectivity is good.