Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers at TU Dresden decipher electrical conductivity in doped organic semiconductors

30.01.2019

Researchers from the Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and the Center for Advancing Electronics Dresden (cfaed) at TU Dresden, in cooperation with Stanford University (USA) and the Institute for Molecular Science in Okazaki (Japan), have identified the key parameters that influence electrical conductivity in doped organic conductors.

Organic semiconductors enable the fabrication of large-scale printed and mechanically flexible electronic applications, and have already successfully established themselves on the market for displays in the form of organic light-emitting diodes (OLEDs).


Illustration of an organic semiconductor layer (green molecules) with dopant molecule (purple)

Sebastian Hutsch, Frank Ortmann

In order to break into further market segments, however, improvements in performance are still needed. Doping is the answer. In semiconductor technology, doping refers to the targeted introduction of impurities (also called dopants) into the semiconductor material of an integrated circuit.

These dopants function as intentional "disturbances" in the semiconductor that can be used to specifically control the behaviour of the charge carriers and thus the electrical conductivity of the original material. Even the smallest amounts of these can have a very strong influence on electrical conductivity.

Molecular doping is an integral part of the majority of commercial organic electronics applications. Until now, however, an insufficient fundamental physical understanding of the transport mechanisms of charges in doped organic semiconductors has prevented a further increase in conductivity to match the best inorganic semiconductors such as silicon.

Researchers from the Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and the Center for Advancing Electronics Dresden (cfaed) at TU Dresden, in cooperation with Stanford University and the Institute for Molecular Science in Okazaki, have now identified key parameters that influence electrical conductivity in doped organic conductors.

The combination of experimental investigations and simulations has revealed that introducing dopant molecules into organic semiconductors creates complexes of two oppositely charged molecules. The properties of these complexes like the Coulomb attraction and the density of the complexes significantly determine the energy barriers for the transport of charge carriers and thus the level of electrical conductivity.

The identification of important molecular parameters constitutes an important foundation for the development of new materials with even higher conductivity.

The results of this study have just been published in the renowned journal "Nature Materials". While the experimental work and a part of the simulations were conducted at the IAPP, the Computational Nanoelectronics Group at the cfaed under the leadership of Dr. Frank Ortmann verified the theoretical explanations for the observations by means of simulations at the molecular level. In doing so, a comprehensive foundation for new applications for organic semiconductor technology has been created.

The research was funded by the German Research Foundation (DFG) through the LE-747/44-1 and OR-349/1 projects, by the Federal Ministry of Education and Research (BMBF) through the UNVEiL project, by the German Academic Exchange Service (DAAD) and the Graduate Academy of the TU Dresden through the great!ipid4all programme, and by the European Research Council through the European Union Seventh Framework Programme (n°607232).

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 the charge transport properties of innovative semiconductor materials. Organic semiconductors are currently at the heart of this research, which is being funded by the German Research Foundation as part of the Emmy Noether Program. The group has been located at cfaed since 2017.

Wissenschaftliche Ansprechpartner:

Prof. Karl Leo
Dresden Integrated Center for Applied Physics and Photonic Materials, TU Dresden
Tel. +49-(0)351-463-37533
karl.leo@iapp.de

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

Originalpublikation:

Title of the article: "Molecular parameters responsible for thermally activated transport in doped organic semiconductors" (Nature Materials)
DOI: 10,1038/s41563-018-0030-8
Release date: January 28, 2019
Authors: Martin Schwarze, Christopher Gaul, Reinhard Scholz, Fabio Bussolotti, Andreas Hofacker, Karl Sebastian Schellhammer, Bernhard Nell, Benjamin D. Naab, Zhenan Bao, Donato Spoltore, Koen Vandewal, Johannes Widmer, Satoshi Kera, Nobuo Ueno, Frank Ortmann, Karl Leo

Weitere Informationen:

http://www.iapp.de
http://www.cfaed.tu-dresden.de/ortmann-home

Kim-Astrid Magister | Technische Universität Dresden

More articles from Physics and Astronomy:

nachricht Initial repulsion does not rule out subsequent attraction
13.09.2019 | Universität Regensburg

nachricht NASA's Hubble finds water vapor on habitable-zone exoplanet for 1st time
12.09.2019 | NASA/Goddard Space Flight Center

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: The working of a molecular string phone

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.

This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.

Im Focus: Milestones on the Way to the Nuclear Clock

Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.

If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...

Im Focus: Graphene sets the stage for the next generation of THz astronomy detectors

Researchers from Chalmers University of Technology have demonstrated a detector made from graphene that could revolutionize the sensors used in next-generation space telescopes. The findings were recently published in the scientific journal Nature Astronomy.

Beyond superconductors, there are few materials that can fulfill the requirements needed for making ultra-sensitive and fast terahertz (THz) detectors for...

Im Focus: Physicists from Stuttgart prove the existence of a supersolid state of matte

A supersolid is a state of matter that can be described in simplified terms as being solid and liquid at the same time. In recent years, extensive efforts have been devoted to the detection of this exotic quantum matter. A research team led by Tilman Pfau and Tim Langen at the 5th Institute of Physics of the University of Stuttgart has succeeded in proving experimentally that the long-sought supersolid state of matter exists. The researchers report their results in Nature magazine.

In our everyday lives, we are familiar with matter existing in three different states: solid, liquid, or gas. However, if matter is cooled down to extremely...

Im Focus: World record for tandem perovskite-CIGS solar cell

A team headed by Prof. Steve Albrecht from the HZB will present a new world-record tandem solar cell at EU PVSEC, the world's largest international photovoltaic and solar energy conference and exhibition, in Marseille, France on September 11, 2019. This tandem solar cell combines the semiconducting materials perovskite and CIGS and achieves a certified efficiency of 23.26 per cent. One reason for this success lies in the cell’s intermediate layer of organic molecules: they self-organise to cover even rough semiconductor surfaces. Two patents have been filed for these layers.

Perovskite-based solar cells have experienced an incredibly rapid increase in efficiency over the last ten years. The combination of perovskites with classical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Society 5.0: putting humans at the heart of digitalisation

10.09.2019 | Event News

Interspeech 2019 conference: Alexa and Siri in Graz

04.09.2019 | Event News

AI for Laser Technology Conference: optimizing the use of lasers with artificial intelligence

29.08.2019 | Event News

 
Latest News

Low sea-ice cover in the Arctic

13.09.2019 | Earth Sciences

Researchers produce synthetic Hall Effect to achieve one-way radio transmission

13.09.2019 | Power and Electrical Engineering

Penn engineers' new topological insulator reroutes photonic 'traffic' on the fly

13.09.2019 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>