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The new graphene nano-belt has been developed successfully, and its sensitivity is unprecedented!

A new study from the university of Nebraska, Nebraska, says that the DNA size of a carbon belt attached to a gas sensor can improve its sensitivity much better than any other known carbon material.

The team developed a new form of nano-tape made of graphene, a 2-dimensional honeycomb of carbon atoms. When researchers to integrate the nano foil membrane into gas sensor circuit, and the performance of the sensor, and even the best compared to carbon materials, it is about 100 times higher than that of sensitivity to the molecules.

"We have previously studied sensors based on other carbon-based materials, such as graphene and graphene oxide," said Alexander Sinitskii, an associate professor of chemistry in Nebraska. "In the case of the graphene nanometer, we're sure we'll see some sensor responses, but we didn't expect it to be higher than ever.

In a study published in the journal Nature, the researchers showed that the molecules of the gas could significantly alter the resistance of the nanoparticles. Different gases produce varying resistance characteristics that allow sensors to distinguish between them.

"There are multiple sensors on the chip and we can show that we can distinguish molecules that have almost the same chemical properties," said Sinitskii, a member of the Nebraska materials and nanoscience center. "For example, we can decompose methanol and ethanol, so these graphene-based sensors are not only sensitive but also selective.


This rendering shows that the gas molecules have widened the gap between the team's graphene nanobelts. Alexander sinisky, of Nebraska, and his colleagues suggest that this phenomenon partly explains how the nanoribbon provides an unprecedented sensitivity to sensors.

Sinitskii and his colleagues suspect that the apparent performance of the nanoribbons is partly due to the unusual interaction between the ribbon and the gas molecules. Unlike its predecessors, the team's nano-ribbon - similar to the line of Charlie brown's shirt stripes - is placed vertically instead of lying flat on the surface. The team suggested that the molecules could separate the lines, effectively extending the gap between the nanobands, and electrons had to jump to conduct electricity.

Graphene, which was awarded the Nobel Prize in 2004, has unparalleled conductivity. But the material lacks a gap - this requires electrons to gain energy before jumping from an atomic orbital to an external "guide band" that drives electrical conductivity - initially stopping the researchers from turning off the conductivity. This, in turn, poses a challenge to the application of graphene in the electronics of the electrical conductivity that requires adjustment of the material.

A potential solution is to trim the graphene sheet to a nanoscale ribbon, and computer simulations suggest an elusive band gap. Proving that be difficult to attract and retain the graphene related properties of atoms required for precision, so researchers from bottom to top through on certain types of solid surface strategically capture together to the molecules to make ribbon. Although the process is effective and the resulting ribbon does have a gap - it limits researchers to make some ribbons at a time.


Sensor chips can accommodate a team of graphene nano-coated nanofilms. Credit: university of nebraska-lincoln

In 2014, Sinitskii pioneered a method for large-scale production of nano-bands in liquid solutions, a key step in expanding the use of electronic applications. But the membranes made of these nano-belts are not enough for electrical measurements. The team's latest research is adapted to the original chemical method by adding a benzene ring to either side of the first nanoband - six carbon atoms and a ring of hydrogen atoms. These rings widen the ribbon, reducing the gap and improving its transmission capacity.

"People usually don't use graphene nanometers as sensor materials," Sinitskii said. "However, it is also good for the sensors to change the electrical conductivity by several orders of magnitude in the same way that nanobelts are beneficial to devices such as transistors.

"Can design many different kinds of graphene nanobelts with very different characteristics, so far, also only a few types have been proved, but for the chemist has not yet been synthesized ribbon has many interesting theory predicts that, so it is likely to develop in the near future with better sensors or other exciting features performance of new nanoscale.

Natural communication (2017) provides long extended atomic precision graphene nanobelts with enhanced conductivity.

Source: great coffee exploration.