A Hollow Pyramid Microstructure Iontronic Pressure Sensor With High Sensitivity Across a Wide Measuring Range

Capacitive flexible pressure sensors are limited by the compressibility of dielectric materials, which creates an inherent tradeoff between high sensitivity and a wide measurement range. This tradeoff makes it challenging to accurately capture physiological signals that require a wide dynamic range. This study presents an iontronic pressure sensor featuring an array of hollow pyramid microstructures. An electric double layer (EDL) with high interface capacitance was created at the junction of the ionic gel and the electrode, providing an intrinsic mechanism for signal amplification in response to pressure loads. The hollow pyramid microstructure array of ionic gel gives the sensor unique compression characteristics, allowing for better interface contact and more effective structural deformation under pressure. This design endows the structure with outstanding compressibility, which in turn enhances the sensor’s sensitivity and broadens its linear detection range. This sensor achieves a sensitivity of 227.56 kPa⁻¹ over a range of 0–400 kPa and maintains a sensitivity of 58.64 kPa⁻¹ across a wide measurement range of 400–2000 kPa. The device also demonstrates impressive dynamic performance metrics, including rapid response and recovery times, as well as excellent repeatability. It has been successfully deployed for the accurate acquisition of various physiological and movement-related signals, including radial artery pulse, biceps brachii contraction, and finger grasping movements. These results confirm the sensor’s ability to serve as a high-performance measurement device for wearable activity monitoring and robotic perception. Furthermore, the hollow pyramid microstructure offers a versatile design principle that can be applied to other sensing modalities to create devices with broader response ranges and improved sensitivity.