Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Graphene imperfections key to creating hypersensitive 'electronic nose'

23.09.2014

Researchers have discovered a way to create a highly sensitive chemical sensor based on the crystalline flaws in graphene sheets. The imperfections have unique electronic properties that the researchers were able to exploit to increase sensitivity to absorbed gas molecules by 300 times. The study is available online in advance of print in Nature Communications.

Amin Salehi- Khojin, asst professor of mechanical and industrial engineering in the lab with Mohammad Asadi, graduate student and Bijandra Kumar, post doc where they are doing research in graphene sensors. Photo: Roberta Dupuis-Devlin/UIC Photo Services

When a graphene lattice or sheet is formed, its polycrystalline structure has random boundaries between the single-crystal grains. The properties of the lattice are significantly affected by these "grain boundaries," said Amin Salehi-Khojin, UIC assistant professor of mechanical and industrial engineering and principal investigator on the study.

In many applications, grain boundaries are considered faults because they scatter electrons and may weaken the lattice. But Salehi-Khojin and his colleagues showed that these imperfections are important to the working of graphene-based gas sensors. They created a micron-sized, individual graphene grain boundary in order to probe its electronic properties and study its role in gas sensing.

Their first discovery was that gas molecules are attracted to the grain boundary and accumulate there, rather than on the graphene crystal, making it the ideal spot for sensing gas molecules. A grain boundary's electrical properties attract molecules to its surface.

A theoretical chemistry group at UIC, led by Petr Kral, was able to explain this attraction and additional electronic properties of the grain boundary. The irregular nature of the grain boundary produces hundreds of electron-transport gaps with different sensitivities.

"It's as though we have multiple switches in parallel," said graduate student Poya Yasaei, first author on the paper. "Gas molecules accumulate on the grain boundary; there is a charge transfer; and, because these channels are all paralleled together, all the channels abruptly open or close. We see a very sharp response."

Researchers have been trying to develop a highly sensitive and robust sensor for decades, said UIC postdoctoral fellow Bijandra Kumar, a co-author on the paper.

"We can synthesize these grain boundaries on a micrometer scale in a controlled way," Kumar said. "We can easily fabricate chip-scale sensor arrays using these grain boundaries for real-world use."

Salehi-Khojin said it should be possible to "tune" the electronic properties of graphene grain-boundary arrays using controlled doping to obtain a fingerprint response -- thus creating a reliable and stable "electronic nose."

With the grain boundary's strong attraction for gas molecules and the extraordinarily sharp response to any charge transfer, such an electronic nose might be able to detect even a single gas molecule, Salehi-Khojin believes, and would make an ideal sensor.

###

Other co-authors are Reza Hantehzadeh, Artem Baskin, Nikita Repnin, Canhui Wang and Robert Klie of UIC and Morteza Kayyalha and Yong Chen of Purdue University.

This work was supported by a UIC Startup budget; National Science Foundation DMR Grant No. 1309765; the acquisition of the UIC JEOL JEM-ARM200CF is supported by a MRI-R2 NSF grant, DMR-0959470; resources of the National Energy Research Scientific Computing Center, supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, and the Extreme Science and Engineering Discovery Environment (XSEDE), supported by the NSF Grant No. OCI-1053575; and partial support from the U.S. Defense Threat Reduction Agency.

Jeanne Galatzer-Levy | Eurek Alert!
Further information:
http://www.uic.edu

More articles from Life Sciences:

nachricht New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences

nachricht The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>