Soft circuits — circuits based on flexible substrates — have been a hot topic for years now, in fields from medicine to consumer electronics. Graphene would be a nearly perfect material to use for these circuits, if only we could apply it effectively. While it’s extremely conductive, it’s flaky and difficult to manufacture at scale.
Unlike metal wiring, which you can melt and deposit, graphene doesn’t really melt. Most conductive ink or paint is made with finely powdered metal. When it dries, the metal particles are close enough to pass through a limited amount of current. Graphene sheets don’t self-assemble from a slurry of carbon atoms in solution, though, and if you try to start with big graphene sheets in solution, they tend to clog nozzles. Worse, they don’t dry flat, and that means a tiny conductive cross-section, high resistance, and terrible performance. Is Scotch tape really our best option for making graphene sheets?
There has to be a better way. A team of Chinese researchers just offered their take on the problem. They’ve come up with a way to print soft circuits using graphene ink — and the method keeps the graphene flakes in the same plane, making the printed graphene traces much more effective.
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