Study unveils new future for coal

A new study has shown the potential for coal’s future usage in high tech devices.

Researchers at MIT have uncovered a way to harness coal in new ways, using thin films of the material for electronic devices.

“Disordered carbon materials, both amorphous and with long-range order, have been used in a variety of applications, from conductive additives and contact materials to transistors and photovoltaics,” researchers Brent D. Keller, Nicola Ferralis, and Jeffrey C. Grossman explain in their paper in Nano Letters.

“We show a flexible solution-based method of preparing thin films with tunable electrical properties from suspensions of ball-milled coals following centrifugation.”

Grossman went on to explain, “When you look at coal as a material, and not just as something to burn, the chemistry is extremely rich.”

He asked: “Could we leverage the wealth of chemistry in things like coal to make devices that have useful functionality?”

In their research, they found that different types of coal – without the refining processes typically needed for electrical components such as silicon – have ranges of electrical conductivities that span more than seven orders of magnitude.

“The measured hopping energies demonstrate electronic properties similar to amorphous carbon materials and reduced graphene oxide,” their paper states.

Keller told MIT News coal has never been studied in terms of its potential use in electronic devices.

“The material has never been approached this way before, to find out what the properties are, what unique features there might be,” he said.

The method of processing the material involves crushing the coal to a powder, putting it into a solution, and then spreading it as a thin, uniform film on a substrate – a step used in creating many different electronic devices such as transistors or photovoltaics.

The researchers found simply by adjusting the temperature at which they processed the coal the material’s optical and electrical properties could be fine-tuned.

Grossman went on to state that the low cost of the material, combined with these low fabrication costs, provide a potential new avenue for coal, and unlike grapheme or silica, does not require high levels of purity in its processing.

The study was supported through a Bose Fellows program and oil and gas company ExxonMobil through the MIT Energy Initiative and the ExxonMobil Fellow program.


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