So far we’ve showcased paper artwork, robots and USB drives here on Inhabitat – and now researchers at the Max Planck Institute of Colloids and Interfaces in Potsdam-Golm have utilized sheets of paper to create targeted conductive structures. Using an inkjet printer, the team was able to deposit a catalyst on paper and heat it, turning the surface into graphite that is able to conduct electricity. The team, Led by Cristina Giordano, is now pioneering the field of carbon electronics.
For most scientists working on flexible electronics, plastics have been the substrate of choice. While they do a good job of moving electrons, they are all sensitive to heat. This becomes a problem, as some of their processing temperatures reach over 400 degrees Celsius. Carbon electronics, on the other hand, are able to withstand up to 800 degrees Celsius, and the paper base is cost-effective, lightweight, and is easy to produce in both flat and three dimensional structures.
To fabricate their electronics, the Potsdam researchers converted the cellulose in paper into graphite by using an iron nitrate catalyst laid down by a commercial inkjet printer. After being heated to 800 degrees Celsius in a nitrogen atmosphere, the cellulose expelled water until all that was left was pure carbon. These areas become conductive, while the non-printed areas are less able to move electrons.
In an experiment, the scientists printed a picture of Minerva, the Roman goddess of wisdom and symbol of the Max Planck society, onto a sheet of paper. They used the image as a cathode that was then electrolytically coated in copper. To test a three-dimensional structure, the team immersed an origami crane in the catalyst and heated it in a similar fashion. Taking a transmission electron microscope, they were able to record how the catalyst moved through the paper in nanodroplets of the iron-carbon mixture, leaving only graphite.
The researchers are hoping to further develop their techniques, taking advantage of the magnetic properties of the material from the iron carbide. By weakening the paper and controlling the conducting paths of graphite, they are working towards creating graphene, or stacks of carbon sheets stacked on top of one another in the graphite. In the future, it is likely that our cutting edge electronics may use one of the oldest of human inventions.