ORNL’s Yijing Stehle. Photo: ORNL.A new era of electronics and even quantum devices could be ushered in with the fabrication of a virtually perfect single layer of ‘white graphene’, according to researchers at the Department of Energy's Oak Ridge National Laboratory (ORNL).
Technically known as hexagonal boron nitride, white graphene boasts better transparency than graphene, a single-atom-thick layer of carbon, is chemically inert, or non-reactive, and atomically smooth. It also features high mechanical strength and thermal conductivity. Unlike graphene, however, it is an insulator instead of a conductor of electricity, making it useful as a substrate and as the foundation for the electronics in cell phones, laptops, tablets and many other devices.
"Imagine batteries, capacitors, solar cells, video screens and fuel cells as thin as a piece of paper," said ORNL's Yijing Stehle, postdoctoral associate and lead author of a paper published in Chemistry of Materials. She and colleagues are also working on a graphene hexagonal boron two-dimensional capacitor and fuel cell prototype that are not only ‘super thin’ but also transparent.
With their novel process for fabricating ‘perfect’ white graphene, ORNL researchers hope to unleash the full potential of graphene, which has not delivered performance consistent with its theoretical value. They propose doing this by using white graphene as a substrate for graphene, which would have the added advantage of further reducing the thickness and increasing the flexibility of electronic devices.
While graphene, which is stronger and stiffer than carbon fiber, is a promising material for data transfer devices, graphene on a white graphene substrate exhibits several thousand times higher electron mobility than graphene on other substrates. That property could allow data transfers that are much faster than currently possible "Imagine your message being sent thousands of times faster," Stehle said.
The novel process for fabricating ‘perfect’ white graphene utilizes standard atmospheric pressure chemical vapor deposition with a conventional furnace, temperature and time, but there's a twist. This twist is what Stehle describes as "a more gentle, controllable way to release the reactant into the furnace and figuring out how to take advantage of inner furnace conditions. These two factors are almost always neglected."
"I just thought carefully beforehand and was curious," she added. "For example, I remind myself that there are many conditions in this experiment that can be adjusted and could make a difference. Whenever I see non-perfect results, I do not count them as another failure but, instead, another condition adjustment to be made. This 'failure' may become valuable."
Stehle noted that this work is especially significant because it takes the material beyond theory. A recent theoretical study led by Rice University, for instance, proposed using white graphene to cool electronics. According to Stehle, this novel process for producing high-quality layers of hexagonal boron nitride could be cost-effectively scaled up to large production volumes.
"Various hexagonal boron nitride single crystal morphology – triangle to hexagon – formulations have been mentioned in theoretical studies, but for the first time we have demonstrated and explained the process," Stehle said.
This story is adapted from material from ORNL, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.