P-LIG on pine substrate

Pine block transformed into electronic components with laser treatment

Image credit: Rice University

Scientists from Rice University in Texas have turned wood into an electrical conductor, using a laser to blacken its surface into a new type of graphene.

“It’s a union of the archaic with the newest nanomaterial into a single composite structure,” said Professor James Tour, a Rice University chemist.

Laser-induced graphene (LIG) is created by using a laser to heat the surface of a polyimide sheet, leaving the extraordinary, conductive nanomaterial atop the plastic However, for some applications, such as 3D printing with graphene; polyimide is not an ideal choice of substrate.

The researchers attempted to recreate LIG on wood; a renewable, adaptable, environmentally friendly alternative to polyimide. In an inert atmosphere without the presence of oxygen, the heat of the laser does not burn the wood, but transforms the surface into wrinkled flakes of graphene “foam” sheets, with one edge bound to the surface of the wood.

After testing oak, pine and birch, the researchers concluded that pine was the best candidate for producing graphene, thanks to its high lignin (the polymer which forms rigid cell walls in plants) content. The Rice University team decided to call this graphene pine-LIG (P-LIG).

The researchers used P-LIG as a supercapacitor for energy storage, and as electrodes for splitting water by depositing layers of cobalt and phosphorous or nickel and iron onto the graphene to create a pair of electrocatalysts.

“There are more applications to explore,” said Mr Ye. “For example, we could use P-LIG in the integration of solar energy for photosynthesis. We believe this discovery will inspire scientists to think about how we could engineer the natural resources that surround us into better-functioning materials.”

According to Professor Tour, P-LIG held the potential for new biodegradable electronics.

“Graphene is a thin sheet of a naturally occurring mineral, graphite,” he said. So we would be sending it back to the ground from which it came along with the wood platform instead of to a landfill full of electronics parts.”

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