The next generation of electronics could be made of exotic metamaterials, or something quite unexpected and simple: unrefined coal. Coal is frequently burned for energy, but researchers at MIT suggest that this popular material could be even better suited for solar panels, batteries, or electronic devices.
They came to this conclusion after studying coal and, for the first time, characterizing in detail its chemical, electrical, and optical properties. They looked at thin films of four different kinds of coal, and there is even more unlocked potential in hundreds of other varieties that haven’t been studied yet.
The material has never been approached this way before, to find out what the properties are, what unique features there might be.
The researchers discovered that coal didn’t need to be refined in order to be a useful material. Instead, to prepare coal for electronic devices, they simply crushed it into a powder, put it in a solution, and then deposited it in thin films on a substrate. By making slight temperature changes during this process, the researchers were able to tune many of the material’s optical and electrical properties.
Unrefined coal is already inexpensive, and this simple processing method would keep costs low. It is tunable, highly conductive, and stable under temperature changes; in other words, a highly promising material for electronic devices. To demonstrate one possibility, the researchers made an electrical heating device that could be used for defrosting car windows or airplane wings, or as part of a biomedical implant. The researchers describe their study in a paper titled, “Rethinking Coal: Thin Films of Solution Processed Natural Carbon Nanoparticles for Electronic Devices,” in the journal NanoLetters.
