Flexible bimodal sensor array for simulataneous sensing of pressure and temperature
Journal
ADV MATER
Date
2013.10.24
Abstract
Diverse signals generated from the sensing elements embedded in flexible electronic skins (e-skins) are typically induced by strain energy generated through processes such as touching, bending, stretching or twisting. When exposed to these myriad stimuli, eliminating background interferences is critical in discerning and quantifying precise sensing signals. In addition, improving the sensor design and employing appropriate sensing materials suitable for flexible sensors, while possessing a large stimulus-responsiveness, are also desirable. Herein, we demonstrate the fabrication of an integrated e-skin that can differentiate mechanical strain from target sensing signal. In specific, sensing signals in field effect transistors (FETs), coupled with various strains, can be accurately discerned from interferences through the integration of a functional gate dielectric into the FET platform. We demonstrate that by applying alternative current (AC) gate bias technique, we can harness their responsive properties. Specifically, tunability of electro-physical coupling effects in nanocomposite gate dielectrics of barium titanate nano-particles and highly crystalline poly(vinylidene fluoride-trifluoroethylene), as studied by piezo-response force microscopy and electrical characterizations, enabled improvement in the e-skin’s sensing responsiveness, stability and preciseness. Finally, we demonstrate the simultaneous and real-time quantification of various strains subjected to the e-skin’s FET, together with our target sensing signals, to realize multimodal sensing.