Wireless, Smart, Human Motion Monitoring Using Solution Processed Fabrication of Graphene–MoS2 Transistors on Paper

Abstract Combining 2D graphene, which has zero bandgap yet high carrier mobility, with a permanent bandgap of 2D MoS 2 opens up numerous possibilities for development of future electronic devices and sensors. This study reports for the first time the fabrication of flexible all paper based few layer graphene (Gr)–MoS 2 field effect transistor (FET) using biodegradable cellulose paper as a substrate for growing Gr/MoS 2 as well as dielectric and pencil graphite as gate. The as fabricated Gr/MoS 2 transistor exhibits on/off ratio of ≈99 with carrier mobility of 18.7 cm 2 V −1 s −1 , which is remarkable considering the simplicity and low cost of the device fabrication. The Gr/MoS 2 transistor is utilized as strain sensor, which could detect negligible strains as low as 0.5%. Detailed mechanism studies in both resistor and FET configurations with Gr/MoS 2 as a channel are presented to better understand the sensing behavior under both tensile and compressive strain conditions. Further, by interfacing the sensor with the microcontroller, the data are acquired and transferred to the smartphone through bluetooth communication thus enabling human motion monitoring. This low cost, large area Gr/MoS 2 FET based strain sensor has huge potential in wireless wearable electronics, such as artificial electronic skin, medical diagnostics, human machine interface, etc.