Ultra-Wide Linear Flexible Piezoresistive Sensor Based on CVD-Synthesized Monolayer MoS2 Film

Abstract Monolayer MoS2 films exhibit the intrinsic piezoresistive effect, but existing composite MoS2 piezoresistive sensors usually achieve high sensitivity at the cost of a narrow linear detection range, restricting their application in full-scale quantitative pressure monitoring. In this work, centimeter-scale monolayer MoS2 films were grown by CVD, and a nondestructive PU/PMMA water-assisted transfer strategy was proposed to prepare flexible conductive substrates. A water-film packaging method was developed to reduce interfacial contact resistance, expanding the linear response range by 250% versus traditional packaging. Bumped PU packaging layers were further designed to concentrate surface stress, boosting sensitivity by 400% relative to flat structures. The fabricated 403 µm-thick pure monolayer MoS2 sensor realizes a continuous linear response from 0.1 kPa to 200 kPa with a response time of 26 ms and stable signals over 5000 loading cycles. Though the sensor adopts intrinsic single-layer MoS2 without composite conductive fillers and thus has moderate absolute sensitivity, it delivers reliable resolution for both micro airflow and high plantar pressure, showing great potential in multi-scale human motion and physiological signal monitoring.