Under some conditions, these monolayers emit red light 2D materials researchers aim 'beyond graphene'

Monday, July 20, 2015
Under some conditions these monolayers emit red light. Graphic Illustration of Point-of-Care Diagnostics

In the realm of 2D materials, weirdness works

Joshua Robinson recalls the day in 2006 when he learned of a material that is, for all practical purposes, two-dimensional.

At the time, he was a post-doctoral researcher at the Naval Research Laboratory in Washington, D.C. His advisor, Eric Snow, was raving about graphene, a newly isolated form of carbon. A cousin of the widely known buckminsterfullerene (or "buckyballs") and carbon nanotubes, graphene was a flat sheet only one carbon atom thick. The atoms were linked together in a six-sided, chicken-wire pattern, forming a lattice with astonishing properties. It was flexible, transparent, and stronger than steel. It conducted electricity better than copper and heat better than anything. In short, carbon in this form didn't behave like carbon anymore. It acted like an entirely new material.

Graphene became known as the first two-dimensional, or monolayer, material. Indeed, at one-third of a billionth of a meter thick, it’s as close to two-dimensional as a tangible object can get. Graphene is 300,000 times thinner than common printer paper. If the paper was as thick as a six-story building is high, graphene would be the thickness of the original paper.

Robinson was in an ideal position to recognize the importance of two-dimensional (2D) materials. He was working with carbon nanotubes, adapting them to detect minute amounts of airborne substances such as those given off by chemical weapons and explosive devices.

“Graphene was simply an unzipped nanotube,” says Robinson, who is now an assistant professor and Corning Faculty Fellow in the Department of Materials Science and Engineering, Penn State. “Eric was so damn excited that I couldn’t help but start reading about graphene, and instantly became hooked—this ‘new material’ seemed too good to be true.”