Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Marcus regime in organic devices: Interfacial charge transfer mechanism verified

09.05.2019

Physicists from the Research Cluster Center for Advancing Electronics Dresden (cfaed) of the TU Dresden, together with researchers from Spain, Belgium and Germany, were able to show in a study how electrons behave in their injection into organic semiconductor films. Simulations and experiments clearly identified different transport regimes. The study was published now in Nature Communications.

Charge transfer processes play a fundamental role in all electronic and optoelectronic devices. For devices based on organic thin-film technology, these include the injection of the charge carriers via the metallic contacts and the charge transport in the organic film itself.


Device schematics.

a – Schematic cross section of the device.

b – Hot-electron transistor operation. Electrons are injected by applying a negative emitter-base bias, and detected in the molecular semiconductor. These electrons are out of equilibrium with the thermal electrons in the base which cannot be described by a larger temperature. The measurements can be performed either without or with externally applied collector-base bias.

Frank Ortmann

Injection processes at the contacts are of particular interest here because the contact resistances at the interfaces must be minimized for optimum device efficiency. However, such internal interfaces are difficult to access and therefore not yet understood very well.

The team of cfaed research group leader Frank Ortmann (Computational Nanoelectronics Group), together with researchers from Spain, Belgium and Germany, has now shown in a study that the electronic transport mechanism when injected into an organic film can be described by the so-called Marcus hopping model known from physical chemistry.

The model was developed by the American chemist Rudolph Arthur Marcus. Comparative theoretical and experimental investigations unequivocally identified the transport regimes predicted in the Marcus theory.

"The predictions derived by R.A. Marcus in the context of chemical synthesis in the 1950s, in particular the so-called 'inverted Marcus regime', could only be confirmed many decades later by systematic experiments on chemical reactions. For his important theoretical contributions, R.A. Marcus received the Nobel Prize for Chemistry in 1992 ", says Ortmann.

"Now, the observation of the 'Inverted Marcus Region', in which a higher voltage generates a lower current, succeeded for the first time in an organic transistor, in which the injection voltage can be actively controlled", Ortmann continues.

This leads to a better understanding of electronic and optoelectronic organic devices in general. The publication has been published on 7th May, 2019 in the journal "Nature Communications".

About the Computational Nanoelectronics Group
The research group at the Center for Advancing Electronics Dresden (cfaed) headed by Dr. Frank Ortmann investigates electronic properties and charge transport properties of novel semiconductor materials.

Here, organic semiconductors are currently an important focus of the work, which is funded by the German Research Foundation under the Emmy Noether Program. The group has been based at the cfaed since 2017.

Press picture:
HiRes download: https://bit.ly/2Lulciy
Caption: Device schematics. a – Schematic cross section of the device. b – Hot-electron transistor operation. Electrons are injected by applying a negative emitter-base bias, and detected in the molecular semiconductor. These electrons are out of equilibrium with the thermal electrons in the base which cannot be described by a larger temperature. The measurements can be performed either without or with externally applied collector-base bias.

Media inquiries:
Matthias Hahndorf
Center for Advancing Electronics Dresden, TU Dresden
Head of Communications
Tel.: +49 351 463-42847
Email: matthias.hahndorf@tu-dresden.de

Wissenschaftliche Ansprechpartner:

Dr. Frank Ortmann
Center for Advancing Electronics Dresden, TU Dresden
Group Leader Computational Nanoelectronics Group
Tel.: +49 (0)351 463 43260
E-Mail: frank.ortmann@tu-dresden.de

Originalpublikation:

Paper title: “Tuning the charge flow between Marcus regimes in an organic thin-film device” (Nature Communications)
Web: https://www.nature.com/articles/s41467-019-10114-2
DOI: 10.1038/s41467-019-10114-2
Authors: A. Atxabal, T. Arnold, S. Parui, S. Hutsch, E. Zuccatti, R. Llopis, M. Cinchetti, F. Casanova, F. Ortmann, L.E. Hueso


Weitere Informationen:

https://cfaed.tu-dresden.de/ortmann-home

Kim-Astrid Magister | Technische Universität Dresden

More articles from Physics and Astronomy:

nachricht Machine learning enhances light-beam performance at the advanced light source
08.11.2019 | DOE/Lawrence Berkeley National Laboratory

nachricht Flatland light
07.11.2019 | Harvard John A. Paulson School of Engineering and Applied Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Distorted Atoms

In two experiments performed at the free-electron laser FLASH in Hamburg a cooperation led by physicists from the Heidelberg Max Planck Institute for Nuclear physics (MPIK) demonstrated strongly-driven nonlinear interaction of ultrashort extreme-ultraviolet (XUV) laser pulses with atoms and ions. The powerful excitation of an electron pair in helium was found to compete with the ultrafast decay, which temporarily may even lead to population inversion. Resonant transitions in doubly charged neon ions were shifted in energy, and observed by XUV-XUV pump-probe transient absorption spectroscopy.

An international team led by physicists from the MPIK reports on new results for efficient two-electron excitations in helium driven by strong and ultrashort...

Im Focus: A Memory Effect at Single-Atom Level

An international research group has observed new quantum properties on an artificial giant atom and has now published its results in the high-ranking journal Nature Physics. The quantum system under investigation apparently has a memory - a new finding that could be used to build a quantum computer.

The research group, consisting of German, Swedish and Indian scientists, has investigated an artificial quantum system and found new properties.

Im Focus: Shedding new light on the charging of lithium-ion batteries

Exposing cathodes to light decreases charge time by a factor of two in lithium-ion batteries.

Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory have reported a new mechanism to speed up the charging of lithium-ion...

Im Focus: Visible light and nanoparticle catalysts produce desirable bioactive molecules

Simple photochemical method takes advantage of quantum mechanics

Northwestern University chemists have used visible light and extremely tiny nanoparticles to quickly and simply make molecules that are of the same class as...

Im Focus: An amazingly simple recipe for nanometer-sized corundum

Almost everyone uses nanometer-sized alumina these days - this mineral, among others, constitutes the skeleton of modern catalytic converters in cars. Until now, the practical production of nanocorundum with a sufficiently high porosity has not been possible. The situation has changed radically with the presentation of a new method of nanocorundum production, developed as part of a German-Polish cooperation of scientists from Mülheim an der Ruhr and Cracow.

High temperatures and pressures, processes lasting for even dozens of days. Current methods of producing nanometer-sized alumina, a material of significant...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

Smart lasers open up new applications and are the “tool of choice” in digitalization

30.10.2019 | Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

 
Latest News

Turbulence creates ice in clouds

08.11.2019 | Earth Sciences

Manganese nodules: project on environmental impact during deep sea mining

08.11.2019 | Earth Sciences

Laser versus weeds: LZH shows Farming 4.0 at the Agritechnica

08.11.2019 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>