Performance of Pressure Sensors based on Laser Induced Graphene Material on Polymeric Coated Substrate

Abstract

Direct laser writing is an efficient and accurate material forming method with high accuracy, strong selectivity and small influence on adjacent areas. It can be used in the fabrication of graphene through the carbonization of polyimide. The graphitic carbon patterning has shown promising potential for different applications. This work introduces a force sensor based on laser induced graphene (LIG) material, including its fabrication process, microscopic characterization of laser- assisted patterns, the piezoresistive behavior under the applied load. The LIG sensor operates in a pressure range up to 100 N/cm2 with high sensitivity (up to 80 % relative change in the low force range ≤ 25 N) and high cyclic stability which facilitate its potential in the application of health monitoring and even human-computer interaction. Several parameters such as laser power, writing speed and writing resolution were investigated and evaluated by their effect on sensor sensitivity. The sensitivity of the pressure sensor depends on laser power and the initial resistance achieved by laser writing. The advantage of using a PDMS coated Kapton sheet for fabrication of pressure sensors is the increase of sensitivity and stability. However, high laser power is required for the writing.