Flexible Substrate Based Few Layer MoS2 Electrode for Passive Electronic Devices and Interactive Frequency Modulation Based on Human Motion

This paper reports the demonstration of human integrated electronic devices, such as oscillators and RC filters, by utilizing flexible capacitor fabricated using few layer MoS
₂
grown on Al foil via hydrothermal method as electrodes and cellulose paper as a dielectric material. There are no reports of MoS
₂
on flexible substrate being utilized as capacitor electrode and further applied human interactive devices. Advantage of using MoS
₂
on Al foil is the enhanced capacitance upon strain due to the piezoelectric property of few layered MoS
₂
over monolayer MoS
₂
. As the applied strain increases, increase in the capacitance was observed, which is systematically explained by piezoelectric property of MoS
₂
, change in physical dimensions, and air gap between MoS
₂
-Al foil and cellulose paper. Upon application of external strain on capacitor, range of frequencies can be generated by oscillator circuit and the mathematical operations such as differentiation and integration are observed for different input signal using RC filter circuits. Further, the fabricated flexible MoS
₂
capacitor was integrated to human hand and the corresponding frequency modulation with hand movement was recorded. Such a simple technique for fabrication of flexible variable capacitor is a major step ahead in wearable electronics having applications in digital electronics and sensors.