(A) study on high performance and robust metal nanostructured electrodes for wearable electronics

Abstract

Attention of wearable electronics that facilitate the interaction with humans by real-time monitoring of physiological signals in response to environmental changes, but require the high mechanical robustness due to attachment to human body is enlarging with progress of excellent stretchable and foldable electrodes. These robust electrodes can be achieved by metal nanostructures such as metal nanowires, metal nanogrids, and metal nanofibers. However, as-prepared metal nanostructures have lower adhesion with substrates, lower opto-electrical performances, and poor environmental stability, requiring the additional post-treatment for robust electrodes that expands an applicability of wearable electronics. We demonstrate the high opto-electrical and mechanical performance of silver nanowires metal nanostructured electrodes for wearable electronics with chemical reduction process of nanostructures and high adhesion layer between nanostructures and substrate. Chemical reduction of oxide layers on metal nanostructures fuses junctions at nanoscale to improve the opto-electrical performance, and to ensure environmental stability of the interconnected nano-network. Moreover, using an auxiliary donor layer and a simple laminating process and dry process, metal nanostructures can be easily transferred to copy paper as well as various other substrates. Intercalating a polymeric binder between the metal nanostructures and the substrate through a simple printing technique enhances the adhesion, not only guaranteeing high foldability of the electrodes, but also facilitating selective patterning of the metal nanostructured electrodes, showing applicability of the technology to wearable electronics. Finally, we employ a vapor-phase method, initiated chemical vapor deposition (iCVD), for conformal coating and embedding of a silver nanowires electrodes on cloth. The metal nanostructures-embedded electrodes can be monolithically applied onto an arbitrary cloth with strong adhesion and environmental stability.