Ultrasensitive Thin-Film Pressure Sensors with a Broad Dynamic Response Range and Excellent Versatility Toward Pressure, Vibration, Bending, and Temperature

Abstract

Flexible pressure sensors with high sensitivity and wide pressure response range are attracting considerable research interest for their potential applications as e-skins. Nowadays, it seems a dilemma to realize high-performance, multifunctional pressure sensors with cost-effective, scalable strategy, which can simplify wearable sensing systems without additional signal processing, enabling device miniaturization and low power consumption. Herein, pressure sensors with ultrahigh sensitivity and broad response pressure range are developed with a low-cost, facile method by combining strain-induced percolation behavior and contact area contributions. Due to their special surface structure and strain induced conductive network formation behavior, these unique pressure sensors exhibit wide sensing range of 1 Pa-500 kPa, ultra-high sensitivity (1×106 kPa-1and 3.1×104 kPa-1 in the pressure ranges of 1 Pa-20 kPa and 20-500 kPa, respectively), fast signal response (< 50 ms), low detect limit (1 Pa) and high stability over 500 loading/unloading cycles. These characteristics allow the devices work as e-skins to monitor human pulse signals and finger touch. Moreover, these sensors illustrate precise electrical response to mechanical vibration, bending and temperature stimuli, which afford the ability of detecting cell phone call-in vibration signals, joint bending and spatial pressure & temperature distributions, indicating promising applications in next-generation wearable, multifunctional e-skins.