Biodegradable components could come to a store ... and then a compost heap near you (Credit: KIT)
Some day soon your obsolete gadgets could be as compostable as banana peels and spent coffee grounds. Researchers from the Young Investigator Network at Karlsruhe Institute for Technology (KIT) in Germany are developing printed electronics from natural and compostable materials that could help make a dent in the millions of tons of electronic waste piling up worldwide each year.
Instead of silicon, heavy metals and other elements that can stick around for a while, even potentially creating toxic hazards as they break down in landfills, the researchers are working with biodegradable materials including semiconductors and dyes made of plant extracts and insulators fashioned out of gelatin.
"These may not be as long-lived as the inorganic alternatives, but they easily survive the service life of disposable electronics," says Dr. Gerardo Hernandez-Sosa, leader of the Young Investigator Group of KIT.
When they're no longer needed, he says the components can be thrown in with biowaste or compost where they will rot like any other organic matter that decomposes. He notes however, that some products with the word "organic" in their names like organic light-emitting diodes (OLEDs) aren't biodegradable in the same way.
"We call all synthetic materials that are based on carbon 'organic'. But this term does not tell us anything about environmental compatibility," he explains.
Instead of using metals or metalloids like silicon, the researchers are working with carrier foils made from natural materials like starches and cellulose, similar to the recent work of a Wisconsin-based team. Hard gelatins like those used to make drug capsules can also be good for insulation.
A key part of creating fully biodegradable electronics will be developing inks for printing circuits that have all the required environmental and conductive properties and also won't plug printers, among other concerns.
Addressing this challenge is the current focus of the research team. The scientists hope to have compostable organic electronics ready for suppliers or store shelves in about three years.