Lincoln, Neb., June 8th, 2015 — Graphene has garnered much attention for its potential to improve electronics, solar cells and other devices. A University of Nebraska-Lincoln chemist is using his breakthrough graphene production technique to put the promising nanomaterial to the test.

Alexander Sinitskii, assistant professor of chemistry, has earned a five-year, $538,477 Faculty Early Career Development Program Award from the National Science Foundation to investigate graphene’s properties. These prestigious grants, known as CAREER awards, support pre-tenure faculty who exemplify the role of teacher-scholars through outstanding research, excellent education and the integration of education and research.

Sinitskii is capitalizing on a technique he developed to create atomically precise graphene nanoribbons, ultra-narrow bands of one-atom thick sheets of carbon. He and his team build the ribbons from the bottom up, using organic chemistry techniques to couple smaller molecules together.

That level of precision allows Sinitskii to create nanoribbons with different widths and edges, such as adding nitrogen or hydrogen atoms. Now he’s investigating how these differing characteristics influence the nanoribbons’ properties.

Scientists have studied graphene nanoribbons theoretically for many years. These studies predicted that physical properties of nanoribbons strongly depend on their structural parameters.

"But until recently there were no synthetic techniques to make those materials and test the predictions. Now we have an opportunity to study graphene nanoribbons experimentally and confirm their predicted properties," said Sinitskii, a member of both UNL’s Nebraska Center for Materials and Nanoscience and its NSF-funded Materials Research Science and Engineering Center.

Understanding changes in nanoribbon properties will help Sinitskii and others design materials with the best performance for diverse applications.

For example, graphene is touted for its conductivity. But it conducts electrons so well, it’s hard to control for use in electronics.

Sinitskii’s nanoribbons are able to harness graphene’s conductivity for use as a semiconductor in electronics. He will experiment with various nanoribbon characteristics to test and optimize its semiconductive potential.

Graphene nanoribbons also have photovoltaic properties. Creating a variety of nanoribbons capable of absorbing photons from a wide range of the sun’s energy wavelengths could improve solar cell efficiency, he said.

Fuel cells may benefit from graphene nanoribbons as well. Fuel cells generate electricity from the energy in fuel through a chemical reaction. The nanoribbons can act as a catalyst to speed up certain reactions, improving fuel cell efficiency. Preliminary evidence suggests adding nitrogen atoms to the nanoribbons’ edges improves their catalytic capabilities.

Sinitskii plans to develop prototype devices incorporating graphene nanoribbons.

"We will synthesize different varieties of graphene nanoribbons and test them for applications in electronics, photovoltaics and catalysis," he said.

With the CAREER award, Sinitskii also will develop new nanoscience courses and conduct outreach activities to promote graduate, undergraduate and high school student education in materials chemistry and nanofabrication.

Writer: Gillian Klucas, Research and Economic Development