New conductive nano inks designed for printed electronics

According to Bayer, once BayInk TP S and TP CNT are adhered to plastic films, flexible substrates, glass and silicon, they provide highly stable structures. The properties of the new aqueous products are the result of adding nanoparticles. BayInk TP CNT contains Baytubes carbon nanotubes - an ink designed to enable production of switches and other electronic elements using traditional printing processes. This removes the need for resintering. BayInk TP S is based on silver nanoparticles. The dispersion can be used to produce conductor tracks and circuits using inkjet technology, for example. The resintering this requires can be performed at temperatures below 140^°C. According to Bayer, this results in conductivity amounting to up to 35% of that of solid silver, depending on the sintering conditions. The fact that the silver particles in BayInk TP S lie in the nanometer range makes it easier for them to melt during sintering. This enables the ink to be used at low temperatures to create more conductive structures than are possible with conventional screen printing pastes containing silver. Dr Daniel Rudhardt (pictured), Bayer's global head of research and development for conductive materials, said: "This makes them ideal in supporting the concept of flexible, inexpensive electronics. They also have the potential for use in conventional electronic components, where they can replace metallisation with its complex process technology." Rudhardt says areas of application could include e-books or rollable screens but also electrically conductive structures in vehicles, such as integrated receiving antennae for navigation systems. "We are open to development partnerships at all stages of the value added chain," he added. Researchers from Bayer say they have amassed wide ranging expertise in nanoparticle dispersion in aqueous media. The challenge is to stabilise particles with relatively small quantities of additives. A high proportion of emulsifiers would greatly reduce the conductivity of the printed electronics. The processes developed also allow production of these nano inks in larger volumes while maintaining the same quality.