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.
Keywords: flexible pressure sensor; high sensitivity; iontronic sensor; multilayer double-sided microstructures; ultrabroad linear working range.