Highly Sensitive, Flexible Pressure Sensors Based on Carbon Nanotube Microfibers Hybridized with Au Flowers

Abstract

Pressure-sensitive electronic skin (e-skin) has gained importance in the fields of prosthetics, health monitoring, sensitive tactile information display, and robotics. In particular, many previous studies have reported flexible and highly sensitive pressure sensors. Among them, e-skin devices based on CNT microfibers show wearable and excellent multimodal (pressure, temperature, humidity, and presence of chemicals) sensing capabilities However, the low sensitivity of these devices at high pressures remains a critical issue. Here, we report on highly flexbile and sensitive e-skin devices prepared by carbon nanotube (CNT) microfibers hybridized with Au flowers, which were synthesized by electrochemical methods. First, we controlled the voltage and reaction time in order to optimize the surface morphology of the CNT microfibers. Next, we fabricated capacitive pressure sensors to elucidate the impact of Au flowers on the sensing capability of the CNT microfiber-based pressure sensors, especially in high pressure regimes. The sensors based on CNT microfibers with Au flowers showed fourfold higher sensitivity than did those without the Au flowers, due to the enhanced air traps between the Au flowers. Furthermore, this morphology of CNT microfibers with Au flowers demonstrated satisfactory repeatability and durability under high pressure.