HC Plastics News: A new study from the University of Nebraska-Lincoln says that fixing a DNA-like ribbon to a gas sensor can improve its sensing sensitivity, far superior to all known carbon materials.
The team developed a new form of nanoribbon made of graphene, which is a two-dimensional honeycomb composed of carbon atoms. When the researchers integrated the nanoribbon-made film into the gas sensor circuit, the sensor with the nanobelt film responded to the molecule by about 100 more than the original sensor (even the carbon-based material with the best performance). Times.
Alexander Sinitskii, an associate professor of chemistry at Nebraska, said that sensors based on other carbon-based materials, such as graphene and graphene oxide, have been studied. In graphene nanobelt-based sensor testing, we suspected that the sensor's response was observed, but unexpectedly more sensitive than ever before.
Researchers published in the journal Nature Communications believe that gas molecules can significantly change the resistance of nanoribbon films. Different gases have unique resistance characteristics that allow the sensor to distinguish between different gases.
Sinatskii, a member of the Nebraska Center for Materials and Nanosciences, said: "There are multiple sensors on the chip that are sufficient to distinguish molecules with almost the same chemical properties, such as methanol and ethanol. Thus, similar to graphene nanoribbon-based sensors are not only sensitive. High and selective."
The rendered image shows that the gas molecules expand the spacing between the graphene nanoribbons. Nebraska's Alexander Sinitskii and colleagues suggest that this phenomenon explains to some extent how the nano-ribbons have improved the sensitivity of the sensor as never before.
Sinitskii and colleagues predict that the extraordinary performance of nanoribbons is partly due to the unusual interaction between nanoribbons and gas molecules. Unlike previous graphene materials, the team's nanoribbon arrangement is similar to Charlie Brown's shirt stripe, which replaces the horizontal distribution vertically downwards. The team suggested that gas molecules can separate these stripes, effectively extending the nanoribbon gap, and electrons must skip these stripes to conduct electricity.
Entry of benzene ring
Graphene was discovered in 2004 and won the Nobel Prize for its unparalleled conductivity. However, given the lack of band gaps in graphene materials (bandgap requires electrons to gain energy before being driven by conductivity to jump from the orbit around the atom to the outer "conduction band"), researchers are unable to control the amount of conductivity. This poses a challenge to graphene applications, the field of electronics that require adjustment of material conductivity.
A potential solution is to trim the flake graphene into nanoscale ribbons and computer simulations to build hard-to-capture band gaps. This proves that the difficult-to-retain properties of graphene are closely related to the atomic precision required, so the researchers began to make ribbons by specifically capturing the molecules on a specific type of solid surface from bottom to top. Although this process worked, and the resulting ribbon did have a band gap, this process limited the researchers to making only a few ribbons in a single pass.
In 2014, Sinitskii pioneered a method for mass production of nanoribbons in solution, a key step in expanding electronic application technology. However, the conductivity of these nanobelt films produced in solution is not particularly good, and it is difficult to measure electronically. The team's latest research accommodates the original chemical method by adding a benzene ring (a ring molecule with six carbon atoms and hydrogen atoms) on either side of the first generation of nanoribbons. These benzene rings broaden the ribbon, reduce the band gap, and improve the conductivity of the nanobelt film.
Sinitskii said: "People do not usually use graphene nanoribbons as sensing materials. However, devices with similar properties to nanometers such as transistors (with the ability to increase conductivity by several orders of magnitude) are equally suitable for applications. in".
At present, many different types of graphene nanoribbons with different characteristics can be designed. So far, experiments have proved only a few types. However, there are many interesting theoretical hypotheses for those nanoribbons that have not yet been synthesized, so the new nanobelts are likely to have better sensor characteristics. 
Editor in charge: Wang Ning 12
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