A review of properties influencing the conductivity of CNT/Cu composites and their applications in wearable/flexible electronics

Abstract

During the past few decades, CNT/Cu based composite materials have fascinated the worldwide research community with their phenomenal mechanical and thermal properties. In addition, CNT/Cu composites have shown remarkable electrical properties and have become a booming candidate in the present electrical, semiconductor and packaging industries. Though several research groups have developed CNT/Cu composites with high conductive properties, very few could even come closer to the benchmark conductivity of pure Cu conductors. The conductivity of the composite has shown dependency on several key factors, including CNT alignment, CNT dispersion and material interface, which can be shaped during its fabrication procedures. Each of these factors has shown a significant interdependency and effective tailoring of those factors can result in better composites with enhanced electrical properties while retaining its mechanical robustness. High flexibility and the improved fatigue life have opened the pathways for CNT/Cu composites into flexible/wearable electronics where CNT/Cu has been introduced into energy storage, energy conversion and sensing systems. In this review article, different approaches on achieving enhanced conductive properties will be presented based on the respective factors they have dealt with. On top of the main discussion on composite electrical conductivity, an overview on CNT/Cu composite applications in flexible/wearable electronics will be presented. The discussion on wearable/flexible electronics will be based on their materials, methods and principal functionalities.