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!
Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View
22.06.2018 | University of Sussex
New cellular pathway helps explain how inflammation leads to artery disease
22.06.2018 | Cedars-Sinai Medical Center
Russian researchers together with their French colleagues discovered that a genuine feature of superconductors -- quantum Abrikosov vortices of supercurrent -- can also exist in an ordinary nonsuperconducting metal put into contact with a superconductor. The observation of these vortices provides direct evidence of induced quantum coherence. The pioneering experimental observation was supported by a first-ever numerical model that describes the induced vortices in finer detail.
These fundamental results, published in the journal Nature Communications, enable a better understanding and description of the processes occurring at the...
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
25.06.2018 | Physics and Astronomy
25.06.2018 | Earth Sciences
25.06.2018 | Power and Electrical Engineering