Coal redefined for thin film electronics

April 20, 2016 // By Julien Happich
Taking a new look at coal in MIT's Department of Materials Science and Engineering (DMSE), PhD candidate Brent Keller Jeffrey unearthed new value in raw coal, as a prime material for electronics.

Rather than merely considering the material as a fossil fuel or as a raw source of carbon for the petrochemical industry, Keller and his colleagues studied the raw material properties, once processed into thin films.

The student developed a series of steps to crush the material to a powder, put it in solution, then deposit it in thin uniform films on a substrate, in order to fabricate electronic devices and characterize them.

As a first demonstration of what they see as a broad range of potential high-tech uses for this traditionally low-tech material, the MIT researchers have succeeded in making a simple electrical heating device that could be used for defrosting car windows or airplane wings, or as part of a biomedical implant.

In developing this initial application, they have also for the first time characterized in detail the chemical, electrical, and optical properties of thin films of four different kinds of coal: anthracite, lignite, and two bituminous types. Their findings have just been reported in the journal NanoLetters.

A simple heating device made by the researchers from unrefined pulverized coal, shown at left under visible light and at right in infrared light, showing the heat produced by the device. Photo courtesy of the researchers