Highly Sensitive Flexible Capacitive Pressure Sensor with ZnO NW interlayers

Abstract

Pressure or force sensors that can reliably detect a broad range of pressure with high sensitivity are prerequisite for applications such as human-machine interface, electronic skin in robotics, and health monitoring. This paper presents a novel approach to fabricate a highly sensitive capacitive pressure sensor by introducing a zinc oxide nanowire (ZnO NW) interlayers between the polydimethylsiloxane (PDMS)/electrodes interface in the conventional metal-insulator-metal architecture. The sensing performances of PDMS-based pressure sensors with and without ZnO NW interlayers were investigated. The ZnO NW interlayers reinforced the electrical connection from metal to PDMS to significantly enhance the device performance with ~50 times improvement in sensitivity (from 0.125 %kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> to 5.6452 %kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at a low-pressure range (0-10 kPa)) with respect to conventional PDMS only dielectric-based capacitive sensors.