MAY 14, 2019 06:00 AM PDT

Ultra-fast Chemical Reaction that Turns Graphene into Semiconductors

A hydrogen atom (blue) hits the graphene surface (black) and forms an ultra-fast bond with a carbon atom (red) (MPI)

German and US scientists recently reported an unusual feat: they observed the world's fastest chemical reaction, during which hydrogen atoms bind onto and then leave a sheet of graphene, all within ten quadrillionths (10^-14) of a second.

Since its discovery in the early 2000s, graphene has been under the limelight of the scientific community for being the material of the future. Although sharing a similar structure with other carbon-based material such as graphite and charcoal, graphene has a lot of unusual properties, steel-beating strength, and remarkable heat and electricity conductivity.

However, graphene isn't perfect: it lacks band gaps, a property that would give graphene the ultimate versatility in electronic and circuitry applications. A band gap is the energy needed for a valence electron to jump from one atom to another within the crystal lattice. The bigger the band gap, the harder for electrons to migrate and the less conductive the material is.

Materials that have large band gaps make good insulators, whereas those with very small or no band gaps are favorable conductors (such as pure graphene). Adding a small or big band gap to graphene can transform it into a semiconductor or an insulator, significantly broadening its usefulness in electronics and circuit boards.

A collaboration group between Max Planck Institute (MPI) and the California Institute of Technology (CalTech) intends to use hydrogen atoms to create a band gap in graphene. To achieve this, they relied on "bunch-compression photolysis", a technique first developed back in 2014 to conduct higher time-resolution experiments that involve reactions by atomic collision.

By bombarding a sheet of graphene inside a high vacuum environment with ultra-short pulses of hydrogen atoms, the researchers observed the scattering of hydrogen atoms from graphene. With the help of their highly time-resolved setup,  they discovered that a transient carbon-hydrogen bond formation as the hydrogen atom lands on the sheet.

It was believed that the hydrogen atom transfers almost all of its kinetic energy to graphene upon collision, a phenomenon the researchers compared to a pebble hitting the water, which triggers a series of waves. Since the bond exists for an extremely short window, the hydrogen atom dissociates right away, and the bond dissipates.

Their results provide the chemistry community eye-opening insights into such type of chemical bonding. Scientists were quite surprised to find that the hydrogen atom can bind more quickly to the carbon atom, which contradicts predictions from the previous modeling.

This discovery was published in the journal Science.

Why graphene hasn’t taken over the world...yet (Verge Science)

Source: ScienceDaily

About the Author
  • With years of experience in biomedical R & D, Daniel is also very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles.
You May Also Like
FEB 12, 2019
Chemistry & Physics
FEB 12, 2019
The Darkest Part of the Universe--Boötes Void
In the northern night sky, you can sometimes find a foreleg-shaped cluster of stars known as the Boötes (Greek word for "herdsman") constell...
FEB 22, 2019
Chemistry & Physics
FEB 22, 2019
The Wandering Pole: Where's Earth's Magnetic North Pole Now?
Although the geographic poles of the Earth (the two ends of Earth's rotation axis) remain by-and-large at the same location over a long period of time,...
MAR 24, 2019
Space & Astronomy
MAR 24, 2019
Could We Power a Spacecraft with a Kugelblitz?
Scientists are always looking for new and efficient ways of powering spacecraft, especially those that will travel far into deep space. The goal is to crea...
APR 11, 2019
Chemistry & Physics
APR 11, 2019
This Bioplastic and Rubber Blend is Biodegradable, Flexible, and Tough
If the over-reliance on petroleum for plastics production is not already a problem, the plastics pollution crisis is and will remain the most concerning en...
APR 25, 2019
Chemistry & Physics
APR 25, 2019
The Perplexing Nature of Time (Part III): Hawking's Guide to Time Travel
What if I tell you time travel is easier than it looks? Don't have to take my word for it. But in Stephen Hawking's last book for the general publi...
APR 28, 2019
Space & Astronomy
APR 28, 2019
Is it Possible for a Moon to Have its Own Moon?
Moons occur throughout our solar system. The Earth only has one, but other sport several, including Mars, Jupiter, and Saturn, to name a few. But given the...
Loading Comments...