Asymmetric microdome structured flexible and skin-mountable pressure sensors monitored with computational analysis

Abstract

Flexible pressure sensors are a crucial component in the next generation of wearable electronics. However, the lack of a structural design strategy that can achieve both high sensitivity and a straightforward manufacturing method remains a challenge. This study proposes a novel solution with an asymmetric microdome structure consisting of different radius sizes fabricated by a simple and cost-effective method. Additionally, large-sized reduced graphene oxide is utilized as a sensing material to improve the electrical conductivity by facilitating electron transfer within its large basal plane. The fabricated sensor shows high sensitivity of 63.07 kPa⁻¹ up to 0.5 kPa and 1.96 kPa⁻¹ in the range of 0.5–10 kPa. The finite element method validates a gradual increase in the number of contact points and area as the applied pressure increases in the asymmetric microdome structure. Moreover, the sensor exhibits a fast response time of 50 ms, excellent repeatability, and mechanical durability over 1000 cycles. Consequently, the sensor is successfully utilized in monitoring the weak radial arterial pulse and detecting various human motions, including wrist bending, phonation, and swallowing activity. The real-time wireless monitoring of daily activities further establishes the sensor's potential for future wearable electronics.