Understanding electron transport in graphene nanoribbons

Date:
September 11, 2020
Source:
Springer
Summary:
New research aims to better understand the electron transport
properties of graphene nanoribbons (GNRs) and how they are affected
by bonding with aromatics - a key step in designing technology
such as chemosensors.



FULL STORY ========================================================================== Graphene is a modern wonder material possessing unique properties
of strength, flexibility and conductivity whilst being abundant
and remarkably cheap to produce, lending it to a multitude of useful applications -- especially true when these 2D atom-thick sheets of carbon
are split into narrow strips known as Graphene Nanoribbons (GNRs).


==========================================================================
New research published in EPJ Plus, authored by Kristians Cernevics,
Michele Pizzochero, and Oleg V. Yazyev, Ecole Polytechnique Federale
de Lausanne (EPFL), Lausanne, Switzerland, aims to better understand
the electron transport properties of GNRs and how they are affected
by bonding with aromatics. This is a key step in designing technology
such chemosensors.

"Graphene nanoribbons -- strips of graphene just few nanometres wide
-- are a new and exciting class of nanostructures that have emerged
as potential building blocks for a wide variety of technological
applications," Cernevics says.

The team performed their investigation with the two forms of GNR,
armchair and zigzag, which are categorised by the shape of the edges of
the material. These properties are predominantly created by the process
used to synthesise them. In addition to this, the EPFL team experimented p-polyphenyl and polyacene groups of increasing length.

"We have employed advanced computer simulations to find out how
electrical conductivity of graphene nanoribbons is affected by chemical functionalisation with guest organic molecules that consist of chains
composed of an increasing number of aromatic rings," says Cernevics.

The team discovered that the conductance at energies matching the energy
levels of the corresponding isolated molecule was reduced by one quantum,
or left unaffected based on whether the number of aromatic rings possessed
by the bound molecule was odd or even. The study shows this 'even-odd
effect' originates from a subtle interplay between the electronic states
of the guest molecule spatially localised on the binding sites and those
of the host nanoribbon.

"Our findings demonstrate that the interaction of the guest organic
molecules with the host graphene nanoribbon can be exploited to detect the 'fingerprint' of the guest aromatic molecule, and additionally offer a
firm theoretical ground to understand this effect," Cernevics concludes: "Overall, our work promotes the validity of graphene nanoribbons
as promising candidates for next- generation chemosensing devices."
These potentially wearable or implantable sensors will rely heavily on
GRBs due to their electrical properties and could spearhead a personalised health revolution by tracking specific biomarkers in patients.


========================================================================== Story Source: Materials provided by Springer. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Kristiāns Čerņevičs, Michele Pizzochero, Oleg V.

Yazyev. Even-odd conductance effect in graphene nanoribbons induced
by edge functionalization with aromatic molecules: basis for novel
chemosensors. The European Physical Journal Plus, 2020; 135 (8)
DOI: 10.1140/epjp/s13360-020-00696-y ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200911110802.htm

--- up 2 weeks, 4 days, 6 hours, 50 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)