The Influence of Mechanical Properties of Dielectric Material and Structure of Electrodes on Capacitive Sensor Properties

摘要

Capacitive sensors are an important component of various intelligent electronics, which is mainly composed of electrodes and dielectric layer. How to improve the sensitivity, repeatability and response speed of the capacitive sensor has attracted much attention. In this study, we investigate the influence of structure of electrodes and mechanical properties of dielectric materials on capacitive pressure sensor performance. We fabricated capacitive sensors with PDMS and Ecoflex silicone elastomer as dielectric layer, respectively. What’s more, ITO and AgNWs network were used as electrodes for comparison. Characteristics of the above sensors were measured. The results demonstrate that Ecoflex silicone elastomer illustrates better sensitivity compared to PDMS, because Ecoflex silicone elastomer is easier to be deformed under pressure. Besides, nano-pores on the network structure affect effective area of the AgNWs electrodes, but the effective area is just about 1.1% less than monolithic ITO electrode with similar sheet resistance, demonstrating good application potential. What’s more, the rough surface with air voids of AgNWs electrodes benefits the sensitivity of sensor, which also shows good repeatability and response speed.