Printable Copper for Advanced Electronics

Printable metallic conductors, coupled with robust mechanical and thermal stability, exhibit potential for additive manufacturing in radiofrequency electronics. However, their electrical conductivity is indispensable for realizing their potential in microwave communication, particularly considering the essential aspect of miniaturization in microwave applications. Contemporary research has demonstrated varying success in the use of conductive inks with these methods. These inks include metallic nanostructured inks, carbon nanoscale inks, as well as conductive polymer inks. Metallic inks consistently show a greater viability for printable electronics due to their relatively higher electrical conductivity. This leaves copper as a sustainable alternative due to its low cost and competitive electrical performance. Despite this, there are some inherent challenges to using copper inks. Commonly copper inks have consisted of copper nanostructured inks and copper precursor based molecular decomposition inks. Copper anostructured inks have a greater tendency of ambient condition oxidation as compared to
traditional gold or silver-based inks as well as other copper molecular decomposition inks. Similarly, they often require the use of additives to prevent agglomeration, to enhance printability and decrease their oxidation potential. Although useful, these additives often increase the initial sintering conditions for high electrical conductivity. Therefore, the combination of additive manufacturing techniques using a copper precursor-based ink can prove more effective for the manufacturing of electronic devices.