The necessary metal-based inks typically consist of silver nanoparticles dispersed in a liquid carrier medium. In order to keep the ink stable and printable, the agglomeration and sedimentation of these functional components need to be prevented as long as they are not printed onto a substrate. This is typically done by the addition of organic (usually polymeric) stabilizers that induce repulsion between the metal nanoparticles. Process optimization involves the screening of a wide range of materials, temperatures, and sintering times and typically the resulting resistance is measured only at the end of the process. The measuring probe consists of an evaporated metal line that is covered with a thin isolating layer. In order to prevent direct electrical contact between the probe line and the conductive ink to be tested, the probe line is covered by an insulating layer.

Inkjet printing (IJP) is a highly versatile and useful tool for product development, prototyping, and even small-scale manufacturing in the printed electronics industry. This chapter discusses a number of printed electronic (PE) applications. PE applications make use of inkjet-printed electrically conductive structures. At first sight, IJP might not seem the most obvious method for the manufacturing of these structures and as a result, it is rather new for PE manufacturing. The potential of IJP for PE applications has been demonstrated recently in a variety of academic and industrial research laboratories. These examples are, however, usually achieved on a sheet-to-sheet (S2 S) basis and only on a small scale. Various types of functional electronic materials can be processed into functional structures and devices by IJP. Examples include conductive metallic inks, organic semiconductors, insulators, and many others.