Ultra-sensitive and precisely decoupled pressure and temperature detection with a “soft-hard” asymmetrically structured sensor based on carbon-nanocoils

Multi-function sensors are important in smart devices and integratable systems. However, achieving both high sensing performance and decoupling between signals with a simple device structure and circuit layout remains a great challenge. Herein, we developed an asymmetric “soft-hard” structured device composing of an elastic porous carbon-nanocoil (CNC)/polydimethylsiloxane (PDMS) pressure-sensitive layer and a relatively hard nonporous CNC/PDMS temperature-sensitive layer. The CNCs showed entanglement with one another and strong interaction with the PDMS matrix, and thus the thermal expansion of polymer induced considerable change of contact points and displacement of CNCs. This, along with the tunneling resistance effect, resulted in an ultra-high temperature sensitivity of 3045.95 % °C⁻¹ and a high resolution of 0.05 °C. Meanwhile, the porous CNC/PDMS layer delivered a high capacitive pressure-sensing performance with a low detection limit of 1.5 Pa. Importantly, the layered soft-hard device structure with a shared-electrode layout enabled precise decoupling of temperature and pressure. Our sensor was further demonstrated in object sensing and picking tests, and successfully employed as a false-touch switch, showing its great potential in smart sensing and safety guarding systems.