Ionic Capacitive Pressure Sensor with Enhanced Sensitivity and Broad Detection Range Featuring Hierarchical Microridge Design

Abstract

Sensitivity and detection range are pivotal attributes in the design of flexible pressure sensors. Nonetheless, maintaining a high sensitivity across a wide detection range remains a difficult challenge. In response to this concern, we propose an ionic capacitive flexible pressure sensor that combines an electron double layer mechanism with hierarchical microridge structure. Experimentally, hierarchical microridge structures are fabricated by a low-cost etched polysilicon template method. The sensor demonstrates high sensitivity and segmented linearity over a wide pressure detection range. Within the pressure range of up to 193.06 kPa, the sensor demonstrates a maximum sensitivity of 119.05 kPa^–1 and a maximum linearity of 0.9876. Benefiting from the broad detection range, high sensitivity, and linearity, practical applications around human motion monitoring such as joint motions and pulse detection are demonstrated here. This work provides a strategy for developing capacitive, flexible pressure sensors with high sensitivity over a wide pressure detection range.