Beetle‐Inspired Gradient Slant Structures for Capacitive Pressure Sensor with a Broad Linear Response Range

Abstract Flexible pressure sensors with broad linearity range and excellent sensor‐to‐sensor uniformity have attracted unprecedented attention in the electronic skins, human–machine interfaces, and environmental monitoring. However, challenges including poor sensor‐to‐sensor uniformity owing to the randomness of the used nanomaterials or porous structures and saturated response that leads to a restricted linearity range because of structural stiffening have been yet addressed. Herein, a novel dielectric layer based on beetle‐inspired gradient slant structures (GSS) is proposed to endow capacitive pressure sensors with extensive linearity range and excellent sensor‐to‐sensor uniformity. The excellent compressibility of the GSS due to the bending deformation of the slant pillars significantly enhances sensor sensitivity. The broad linearity range comes from the compensation of contact area during sequential contact of the GSS dielectric layer from tall to low slant pillars with electrodes. The high sensor‐to‐sensor uniformity is ascribed to the excellent batch‐to‐batch consistency of prepared GSS via 3D printing‐based fabrication process. Moreover, the proposed GSS‐based pressure sensors present rapid response/recovery, low detection limit, excellent dynamic response, negligible hysteresis, and outstanding long‐term stability. Finally, the excellent applicabilities of proposed capacitive pressure sensors in diverse scenarios including external pressure stimuli detection, a flexible perception array, and a smart insole system are demonstrated.