Wearable electronics, electronic skins, and human–machine interfaces demand flexible sensors with not only high sensitivity but also a wide linear working range. The latter remains a great challenge and has become a big hurdle for some of the key advancements imperative to these fields. Here, we present a flexible capacitive pressure sensor with ultrabroad linear working range and high sensitivity. The dielectric layer of the sensor is composed of multiple layers of double-sided microstructured ionic gel films. The multilayered structure and the gaps between adjacent films with random topography and size enhance the compressibility of the sensor and distribute the stress evenly to each layer, enabling a linear working range from 0.013 to 2063 kPa. Also, the densely distributed protrusive microstructures in the electric double layer contribute to a sensitivity of 9.17 kPa–1 for the entire linear working range. For the first time, a highly sensitive pressure sensor that can measure loading conditions across 6 orders of magnitude is demonstrated. With the consistent and stable performance from a low- to high-measurement range, the proposed pressure sensor can be used in many applications without the need for recalibration to suit different loading scenarios.

Recent years have seen a rapid development of electronic skin for wearable devices, autonomous robotics, and human–machine interaction. As a result, the demand for flexible pressure sensors as the critical sensing element in electronic skin is also increasing. These sensors need to feature high sensitivity, short response time, low detection limit, and so on. In this paper, inspired from the cobweb in nature, we propose a piezoresistive pressure sensor by forming a cobweb-like network made of a zinc octaethylphorphyrin (ZnOEP)/carbon nanotube (CNT) hybrid on an array of polydimethylsiloxane (PDMS) microposts. The hybrid material exhibits excellent adhesion to PDMS, benefitting from ZnOEP’s low Young’s modulus and the nonpolar bonding between ZnOEP and PDMS such that no delamination and resistance variation are found after thousands of cycles of bending and twisting. With the overhanging morphology of the ZnOEP/CNT network on the micropost array, we realized a pressure sensor with an ultrahigh sensitivity of 39.4 kPa–1, a super-fast response time of 3 ms, a low detection limit of 10 Pa, and a reproducible response without degradation after 5000 cycles of pressure loading/unloading. The sensor can be employed for a variety of applications, including wrist pulse measurement, sound level detection, mechanical vibration monitoring, etc., proving its great potential for use in electronic skin systems.

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