Rational Design of All Resistive Multifunctional Sensors with Stimulus Discriminability

A rational approach is proposed to design soft multifunctional sensors capable of detection and discrimination of different physical stimuli. Herein, a flexible multifunctional sensor concurrently detecting and distinguishing minute temperature and pressure stimuli in real time is developed using electrospun carbon nanofiber (CNF) films as the sole sensing material and electrical resistance as the only output signal. The stimuli sensitivity and discriminability are coordinated by tailoring the atomic- and device-level structures of CNF films to deliver outstanding pressure and temperature sensitivities of −0.96 kPa−1 and −2.44% °C−1, respectively, enabling mutually exclusive sensing performance without signal cross-interference. The CNF multifunctional sensor is considered the first of its kind to accomplish the stimulus discriminability using only the electrical resistance as the output signal, which is most convenient to monitor and process for device applications. As such, it has distinct advantages over other reported sensors in its simple, cost-effective fabrication and readout system. It also possesses other invaluable traits, including good bending stability, fast response time, and long-term durability. Importantly, the ability to simultaneously detect and decouple temperature and pressure stimuli is demonstrated through novel applications as a skin-mountable device and a flexible game controller. © 2021 Wiley-VCH GmbH