Low Temperature (80 °C) Sinterable Particle Free Silver Ink for Flexible Electronics

For the emerging field of flexible printed electronics, ink compatibility with substrate is always required. However, most of the commercial silver nanoparticle-based inks are not compatible with flexible substrates, as they need high- sintering temperatures (~150-250 °C). In addition, silver nanoparticle-based inks have several serious problems such as a complex synthesis protocol, high cost, particle aggregation, nozzle clogging, reduced shelf life, and jetting instability. These shortcomings in conductive inks are barriers for their wide spread use in practical applications. In this work, we demonstrate a silver-organo-complex (SOC) based particle free silver ink which can decompose at 80 °C and becomes conductive at this low temperature. The inkjet-printed film from this ink exhibits not only high conductivity but also excellent jetting and storage stability. To demonstrate the suitability of this ink for flexible electronics, an inkjet-printed film on flexible polyimide substrate is subjected to bending and crushing tests. The results before and after flexing and crushing are very similar, thus verifying the excellent tolerance against bending and crushing for this ink as compared to the commercial nanoparticles based ink.