Preparation And Working Mechanism Of MXene Based Highly Sensitive And Multifunctional Pressure Sensor

As a fundamental device in transferring force signal to electrical signal,pressure sensor plays an important role in mass weighting,human-health monitoring,precision measuring and gesture capturing.However,challenges like low sensitivity,finite sensing range and limited sensing ability refrain the flexible pressure sensor from massive application.To overcome problems mentioned above,MXene are chosen as the core sensitive material in this article to couple with other materials and structure to realize high sensitivity,multifunctional and wide pressure range sensing.The main research content describes as bellow:1.To improve the pressure sensitivity of PTFE film based pressure sensor,we propose the method of introducing MXene material into PTFE film,which could significantly improve its strain rate(450%),tensile strength(50%)and surface charge density(600%)and realize sensitive pressure sensing.The pressure sensor which based on this MXene/PTFE composite film shows high sensitivity(80 V/k Pa)and excellent robustness(keep stable even under 100000 cycles test)2.To help the room-limited microelectronics realize multifunctional sensing,we propose a micro-channel confined effect to improve the sensing ability of MXene and achieve multifunctional applications.The resistivity of the compressible accordion-liked MXene could be changed under external pressure and the micro-channel structured electrode could help the MXene form a three-dimensional stacking structure leading to a larger resistance variation range and higher pressure sensitivity.The pressure sensor based on 78?m micro-channel structured electrode shows the best sensing ability.Its sensitivity is 99.5 k Pa^-1,limit of detection is 9 Pa,response/recovery time is 4 ms/13 ms.In addition,this sensor exhibits an excellent multifunctional micro-force sensing ability like pulse sensing,sound sensing,vibrating sensing and even acceleration sensing.3.To simultaneously build up the sensitivity and detecting range of the pressure sensor,we propose a multisensory mechanism inspired by the human skin.A pressure sensor was prepared with a wide pressure detecting range and high sensitivity by two kinds of MXene/sponges with different mechanical properties.Melamine sponge(called MA)is composed of a large number of fine melamine skeletons and has good elastic property in a small pressure range.The corresponding pressure sensor made by MXene/MA sponge shows excellent force detecting ability in small pressure(less than10 k Pa).Polyurethane sponge(called PU sponge)is composed of a sparse and strong polyurethane skeleton,which can achieve rapid contact among skeletons under the high-pressure range.The corresponding pressure sensor made by MXene/PU sponge shows an outstanding force detecting ability in large pressure(large than 10 k Pa).Through adjusting the concentration of MXene solution and the design of the 0.6 mm thick hollow spacer layer,the integrated pressure sensor can realize continuous current variation during the full detection period.The integrated pressure sensor could achieve high sensitivity(1045 k Pa^-1and 366 k Pa^-1)in both low pressure(less than 10 k Pa)and high-pressure range(10-50 k Pa).Furthermore,the sensor has an ultra-low detecting limit of 1.15 Pa.