New and efficient way to create nanographene for power and display devices

Nanographene is a material that could radically improve solar cells, fuel cells, LEDs, and more. Typically, the synthesis of this material has been imprecise and difficult to control. For the first time, researchers have discovered a simple way to precisely control the manufacture of nanographene. In doing so, they shed light on the previously unclear chemical processes involved in the production of nanographene.

Graphene, layers of carbon molecules one atom thick, could revolutionize future technology. The units of graphene are called nanographene; these are tailored to specific functions and, as such, their manufacturing process is more complicated than that of generic graphene. Nanographene is made by selectively removing hydrogen atoms from organic carbon and hydrogen molecules, a process called dehydrogenation.

“Dehydrogenation takes place on a metallic surface such as that of silver, gold or copper, which acts as a catalyst, a material that allows or accelerates a reaction,” said assistant professor Akitoshi Shiotari of the Department. of advanced materials science. “However, this surface area is large relative to the target organic molecules. This contributes to the difficulty of creating specific nanographene formations. We needed a better understanding of the catalytic process and a more precise way to control it.”

Shiotari and his team, exploring different ways to synthesize nanographene, have come up with a method that provides the precise control needed and is also very efficient. They used a specialized type of microscope called an atomic force microscope (AFM), which measures details of molecules with a needle-like nanoscopic probe. This probe can be used not only to detect certain characteristics of individual atoms, but also to manipulate them.

“We found that the AFM metal probe can break carbon-hydrogen bonds in organic molecules,” Shiotari said. “It could do this very precisely given that its end is so tiny, and it could break bonds without the need for thermal energy. This means that we can now manufacture nanographene components in a more controlled manner than ever before.”

To verify what they were seeing, the team repeated the process with a variety of organic compounds, specifically two molecules with very different structures called benzonoids and nonbenzoids. This demonstrates that the AFM probe in question is capable of extracting hydrogen atoms from different types of materials. Such detail is important if this method is to be extended to a commercial means of production.

“I envision that this technique could be the ultimate way to create functional nanomolecules from the bottom up,” Shiotari said. “We can use AFM to apply other stimuli to target molecules, such as the injection of electrons, electronic fields or repulsive forces. It is exciting to be able to see, control and manipulate structures on such a tiny scale.