Amorphous carbon derived from daily carbon ink for wide detection range, low-cost, eco-friendly and flexible pressure sensor

Abstract

Flexible pressure sensor has important applications in wearable electronic system. However, most reported flexible pressure sensors still face problems such as expensive raw materials, complex preparation processes, and narrow pressure detection ranges. Inspired by low-cost daily carbon ink and filter paper, a flexible pressure sensor is designed and fabricated using a simple dip-coating method. The proposed pressure sensor consists of two filter papers coated with carbon ink as sensitive layers, fabric conductive tapes as flexible electrodes, and polyimide tape as packaging layer. The filter paper has a fibrous microstructure, which is beneficial for improving the pressure sensing performance of the pressure sensor. The main component of carbon ink is amorphous carbon, which has a moderate conductivity. The results indicate that the pressure sensor exhibits wide detection range (0.1–100 kPa), high sensitivity of 0.627 kPa−1 (0.1–15 kPa), short response/recovery times (230 ms/290 ms) and good durability (4000 cycles at 50 kPa). In addition, the pressure sensor can be used for physiological and motion monitoring, such as pulse and step count. This work provides an optional strategy for developing wide detection range, low-cost, eco-friendly and flexible pressure sensor.