Andrea Ferrari and his science team of the University of Cambridge recently discovered a way to print quality electronics. This without any adding of metal. How? They succeeded in strengthening the conductive polymers (type of plastic) with graphene. The problem with printed electronics made out of conductive polymers is the quality. Silicon-based electronics conduct electricity much better. Graphene, a sort of honey grid of carbon atoms that makes graphite, conducts as well as metal. Now that Andrea Ferrari managed to combine graphene with conductive polymers it is for the first time possible to print quality electronics with the same conduction as silicon-based electronics.
Unfortunately, because of the shape of the graphene flakes, it is rather difficult to push the material through the printer head. Graphene is an irregular mixture of small and large flakes. The large flakes clog the printer head and at the same time prevent that small regular droplets are formed.
Ferrari and his team managed to solve this problem. With the use of sonication they can peel off layers of graphene from a block of graphite and at the same time filter them so the biggest flocks don’t clog the printer anymore. Then they solve the flakes in the solvent N-Methylpyrrolidone (better known as NMP) which counteracts the infamous coffee ring effect (a pattern left by a puddle of particle-laden liquid after it evaporates, in this case the ink). This problem needed to be solved when printing delicate electronic parts. In the final stage, the NMP combined with the dissolved graphene flakes are put in the printer head. The researchers printed a couple of circuits and thin-film transistors.
Because of this breakthrough printed electronics can now conduct electricity faster than before but not yet as fast as silicon-based electronics. Note that this product is still in development and not even close to what it is going to be. This opens doors for fully printed graphene based devices on any random surface. Imagine that.