Accordion-Inspired Flexible Pressure Sensor Based on Folded Interdigital Electrode

Flexible piezoresistive pressure sensors have attracted great attention for their wide application in human–machine interfaces, wearable electronics, and so on. However, it is often difficult to obtain sensors with both high sensitivity and wide sensing range. Here, we propose an accordion-inspired piezoresistive pressure sensor as a new solution. The flexible interdigital electrode is bent by mold pressing and then stacked along the compression direction with paper-based conductive sensing layers by appropriate assembly and encapsulation. The stacked structure obviously increases the change and upper limit of contact area between sensing layers and electrodes, which effectively improves the sensitivity of the pressure sensor over the whole sensing range compared to the single-layered structure. Thus, the sensor in this work shows high sensitivities (more than 300 kPa−1) in a wide sensing range (3.6–714.3 kPa), with a maximum value of 1431.7 kPa−1. This work provides a new strategy to design and fabricate piezoresistive pressure sensors with high sensitivity and wide sensing range.