A team of researchers from the University of Arkansas has developed a circuit that can convert the thermal motion of graphene into an electric current. Physicists said that the circuit, which could be incorporated into a chip, provides limitless, clean, and low voltage power for sensors and small devices. The whole idea of developing energy from the graphene circuit is controversial as it rebuts the well-known assertion of Richard Feynman that Brownian motion, or thermal motion of an atom, cannot do work. The study demonstrates that the thermal motion of graphene at room temperature induces an alternating current in a circuit. This is considered to be an achievement as it was always considered to be impossible.
Scientists used two diodes in the graphene circuit to convert alternating current into a direct current (DC) that performs work on a load resistor. The current is allowed to flow both ways with the diodes in opposition which provide separate paths through the circuit and produce a pulsing direct current that performs work on a load resistor. According to Paul Thibado, lead researcher in the discovery and professor of physics, they found that the design amplified the amount of power delivered. “We also found the switch like the on-off feature of the diodes increased the power delivered instead of reducing it, exactly opposite to earlier concept,” he said. Thibado added that the resistance provided by the diodes resulted in the rate of change that adds an extra factor to the power. Scientists used a relatively new physics field to prove the diodes increased the power of the circuit.
Thibado explained that people might think the flow of current in the resistor causes it to heat up, but the Brownian current does not. Scientists now plan to examine in future whether direct current can be used by storing in capacitors. The goal will require miniaturizing the circuit and then patterning it on a silicon chip or wafer. These tiny circuits can provide low power if millions of them can be built on a 1-millimeter by 1-millimeter chip. The finding has been published in the journal Physical Review E. This is an offshoot of research at the University of Arkansas three years ago. Researchers also found a low frequency of the current is induced in the circuit if the motion of graphene is slow.