Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Oregon approach for 'nanohoops' could energize future devices

13.10.2015

While application is down the road, these tiny organic circular structures could be used in solar cells, light-emitting diodes and medical diagnostics

When Ramesh Jasti began making tiny organic circular structures using carbon atoms, the idea was to improve carbon nanotubes being developed for use in electronics or optical devices. He quickly realized, however, that his technique might also roll solo.


Illustration of a cycloparaphenylene, or nanohoop, that has been doped with nitrogen atoms. Research in the University of Oregon lab of Ramesh Jasti has shown the combination of nitrogen and carbon atoms extends the potential efficiency and capabilities of such structures.

Courtesy of Ramesh Jasti

In a new paper, Jasti and five University of Oregon colleagues show that his nanohoops -- known chemically as cycloparaphenylenes -- can be made using a variety of atoms, not just those from carbon. They envision these circular structures, which efficiently absorb and distribute energy, finding a place in solar cells, organic light-emitting diodes or as new sensors or probes for medicine.

The research, led by Jasti's doctoral student Evan R. Darzi, was described in a paper placed online ahead of print in ACS Central Science, a journal of the American Chemical Society. The paper is a proof-of-principle for the process, which will have to wait for additional research to be completed before the full impact of these new nanohoops can be realized, Jasti said.

These barely one-nanometer nanohoops offer a new class of structures -- sized between those made with long-chained polymers and small, low-weight molecules -- for use in energy or light devices, said Jasti, who was the first scientist to synthesize these types of molecules in 2008 as a postdoctoral fellow at the Molecular Foundry at the Lawrence Berkeley National Laboratory.

"These structures add to the toolbox and provide a new way to make organic electronic materials," Jasti said. "Cyclic compounds can behave like they are hundreds of units long, like polymers, but be only six to eight units around. We show that by adding non-carbon atoms, we are able to move the optical and electronic properties around."

Nanohoops help solve challenges related to materials with controllable band gaps -- the energies that lie between valance and conduction bands and is vital for designing organic semiconductors. Currently long materials such as those based on polymers work best.

"If you can control the band gap, then you can control the color of light that is emitted, for example," Jasti said. "In an electronic device, you also need to match the energy levels to the electrodes. In photovoltaics, the sunlight you want to capture has to match that gap to increase efficiency and enhance the ability to line up various components in optimal ways. These things all rely on the energy levels of the molecules. We found that the smaller we make nanohoops, the smaller the gap."

To prove their approach could work, Darzi synthesized a variety of nanohoops using both carbon and nitrogen atoms to explore their behavior. "What we show is that the charged nitrogen makes a nanohoop an acceptor of electrons, and the other part becomes a donator of electrons," Jasti said.

"The addition of other elements like nitrogen gives us another way to manipulate the energy levels, in addition to the nanohoop size. We've now shown that the nanohoop properties can be easily manipulated and, therefore, these molecules represent a new class of organic semiconductors -- similar to conductive polymers that won the Nobel Prize in 2000," he said. "With nanohoops, you can bind other things in the middle of the hoop, essentially doping them to change properties or perhaps sense an analyte that allows on-off switching."

His early work making nanohoop compounds was carbon-based, with the idea of making them different diameters and then combining them, but his group kept seeing unique and unexpected electronic and optical properties.

Jasti, winner of a National Science Foundation Career Award in 2013, brought his research from Boston University to the UO's Department of Chemistry and Biochemistry in 2014. He said the solar cell research being done by his colleagues in the Materials Science Institute, of which he is a member, was an important factor in his decision to move to the UO.

"We haven't gotten very far into the application of this," he said. "We're looking at that now. What we were able to see is that we can easily manipulate the energy levels of the structure, and now we know how to exchange any atom at any position along the loop. That is the key discovery, and it could be useful for all kinds of semiconductor applications."

###

Co-authors with Darzi and Jasti were: former BU doctoral student Elizabeth S. Hirst, who now is a postdoctoral fellow at the U.S. Army Natick Soldier Research, Development and Engineering Center; UO doctoral student Christopher D. Weber; Lev N. Zakharov, director of X-ray crystallography in the UO's Advanced Materials Characterization in Oregon center; and Mark C. Lonergan, a professor in the Department of Chemistry and Biochemistry.

The NSF (grant CHE-1255219), Department of Energy (DE-SC0012363), Sloan Foundation and Camille and Henry Dreyfus Foundation supported the research.

Source: Ramesh Jasti, associate professor, Department of Chemistry and Biochemistry, 541-346-2508, rjasti@uoregon.edu

Note: The UO is equipped with an on-campus television studio with a point-of-origin Vyvx connection, which provides broadcast-quality video to networks worldwide via fiber optic network. There also is video access to satellite uplink and audio access to an ISDN codec for broadcast-quality radio interviews.

Links:

Jasti faculty page: http://chemistry.uoregon.edu/profile/rjasti/
Department of Chemistry and Biochemistry: http://chemistry.uoregon.edu/
Materials Science Institute: http://materialscience.uoregon.edu/
Paper abstract: http://pubs.acs.org/doi/10.1021/acscentsci.5b00269

Media Contact

Jim Barlow
jebarlow@uoregon.edu
541-346-3481

 @UOregonNews

http://uonews.uoregon.edu

Jim Barlow | EurekAlert!

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>