Research On Flexible Pressure Sensor Based On Graphene

Sensing technology is considered to be an important part of the development of science and technology in the 21 st century.Sensing technology,computer technology and communication technology are known as the three pilars of modern information industry,which are widely used in electronics,aerospace,defense,and scientific research And other fields.Modern technology is developing towards intel igence.Flexible sensors that can be used to detect human physiological conditions and wearable health monitoring devices have attracted much attention.At present,researches on flexible sensors are mainly to change the structure of sensors and find sensitive materials with better performance.Graphene has become more and more popular in scientific research due to its excellent electrical,mechanical,and mechanical properties.In this paper,we carefully read the current situation of graphene flexible pressure sensor in recent years,and found that the sensitivity of graphene flexible pressure sensor is very high,which is suitable for detecting weak signals,but the preparation method of the sensor is cumbersome,resulting in increased cost.Based on the analysis of current graphene flexible pressure sensor,a grid structure graphene flexible pressure sensor is proposed.Then,through the COMSOL finite element simulation software,the mechanical simulation of the graphene flexible pressure sensor with grid structure is carried out.The simulation results show that in a certain range,the larger the micro grid structure is,the greater the stress the graphene film bears,and the larger the shape variable of the graphene film is.In this paper,the copper wire mesh is used as the template,PDMS is used as the flexible film,and the grid structure substrate is prepared by the method of embossing.A simple and economical method for the preparation of graphene flexible pressure sensor is proposed in this paper.Graphene thin films were prepared by CVD method.In this experiment,methane was used as carbon source,copper foil as the metal substrate of graphene,argon as the protective gas,hydrogen as the reducing gas.Feldspar was produced in 1050 ? by placing copper foil in CVD tube furnace.In the experiment,the gas flow parameters and growth time parameters were adjusted continuously to prepare different layers of graphene films.The growth parameters of graphene were determined by experiments.In order to test the performance of graphene flexible pressure sensor,a set of signal acquisition system is designed according to the characteristics of graphene flexible pressure sensor.The Huygens differential bridge circuit and amplifying circuit are welded by the resistance and circuit board of the laboratory.The output of the circuit is connected with AD converter and single chip microcomputer.The collected signal is transmitted to the computer through the serial port.The collected data is processed by MATLAB,and the collected signal is displayed in real time by LABVIEW software.According to the collected data,the sensor is analyzed.The sensor is in the range of 0-0.1KPa,the sensitivity can reach 100KPa-1;in the pressure range of 0.1KPa to 4KPa,the sensitivity is 4KPa-1,the resolution of the sensor can reach 0.08 KPa,the response time is 28 ms,the sensor can detect the pressure of 0.008 KPa.Further,this paper tests the detection ability of graphene flexible pressure sensor based on grid structure in terms of weak physiological signals.The sensor is installed on the wrist,chest,and fingers to collect and analyze pulse signals before and after exercise,breath signal acquisition and Analysis,analysis of finger movement status.Through these applications,we know that the sensor can accurately measure weak signals,showing its application potential in wearable devices and human-machine interfaces.