A comparative study of low-cost coatings for inkjet printed silver

Silver is the most widely used conductive material in printed electronics. However, silver in contact with atmospheric gases tarnishes and loses its electrical conductivity within a few weeks. Thus, usually a protective coating on the printed silver is needed. On the other hand, in many printed electronic devices, flexibility and/or working temperature range is important, as well, while these characteristics may be affected by the coating. Here several low-cost polymeric and metallic protective coatings for inkjet printed silver are compared, and their effects on tarnishing, flexibility and working temperature of the inkjet printed silver are investigated and compared to each other. In particular, each coating electrical resistance is studied as a function of temperature, so aging in its accelerated tarnishing environment and mechanical strain are measured. Furthermore, the highest curvature and flexural fatigue of the printed silver associated with each coating is also measured.

Keywords:

inkjet printing , flexible pattern , silver , coating