Featured Research

from universities, journals, and other organizations

Strong Grip: Unexpected interaction between organic semiconductors

Date:
March 9, 2012
Source:
Forschungszentrum Juelich
Summary:
Physicists have discovered an unexpectedly strong bond between organic layers. Such structures are still puzzling scientists throughout the world. These structures form the basis for novel electronic components made from organic semiconductors that are now increasingly used in smart phones and television sets.

Image taken with a scanning tunnelling microscope at -260 °C: in the top right-hand part of the picture, a thin layer of copper phthalocyanine has become attached to a lattice made of PTCDA. The agreement in the arrangement of the different molecules indicates the strong bonding between the two layers.
Credit: Forschungszentrum Jülich

Jülich physicists have discovered an unexpectedly strong bond between organic layers. Such structures are still puzzling scientists throughout the world. These structures form the basis for novel electronic components made from organic semiconductors that are now increasingly used in smart phones and television sets.

The results have been published in the journal Physical Review Letters.

Organic semiconductors are cheap to produce, can be flexibly shaped and are relatively insensitive to external influences. In principle, they could in future even be simply printed on plastic foils. They are already widely used as organic light-emitting diodes (OLEDs), particularly in smart phones, because they consume so little power. Nevertheless, the electronic properties of these complex materials still remain largely unknown. Researchers are particularly interested in the interfaces because component performance decisively depends on how well contacts can be created with other organic and metallic conductors. The stronger the bond, the better electrons can pass from one material to the other -- and the more power or light can be produced by solar cells or light-emitting diodes.

However, organic molecules do not usually form such strong bonds. "Scientists have assumed that organic materials only interact among themselves via weak van der Waals forces. Only in contact with certain metals do they display stronger bonding known as chemisorption," says Dr. Christian Kumpf from Forschungszentrum Jülich. "For the first time, we have been able to demonstrate such chemisorption between two organic layers, which we applied to a silver crystal by chemical vapour deposition." Such sandwich-like structures are also found in OLEDs and usually consist of several organic layers between two metallic conductors.

For the analysis, Kumpf and his colleagues made use of PTCDA, an organic semiconductor material, and copper phthalocyanine, which is frequently used as a dye. They then investigated the layers, which are only one molecule thick, using various highly specialized measuring techniques. By means of ultraviolet photoelectron spectroscopy (UPS), the researchers were able to show that a change is transferred between the organic semiconductors. They also used scanning tunnelling microscopy (STM) and low-energy electron diffraction (LEED) to demonstrate that the arrangement of the molecules is transferred to the next layer in the order of the strong bonding, almost like a photocopy.

It has been known for some time that certain metals can establish such strong interactions with an organic semiconductor. In his earlier work, Kumpf himself contributed to research in this field, even before moving to Prof. Stefan Tautz's group in Jülich in 2008. "What is new is that the charge transfer takes place between these organic materials, that was rather unexpected. These findings will undoubtedly be exploited in the development of new organic semiconductors," says Tautz, director at the Jülich Peter Grünberg Institute (PGI-3: Functional Nanostructures at Surfaces). There is, however, still a long way to go since industrial manufacturing processes and laboratory requirements are quite different; the latter being more concerned with reproducibility and precision.


Story Source:

The above story is based on materials provided by Forschungszentrum Juelich. Note: Materials may be edited for content and length.


Journal Reference:

  1. Benjamin Stadtmüller, Tomoki Sueyoshi, Georgy Kichin, Ingo Kröger, Sergey Soubatch, Ruslan Temirov, F. Tautz, Christian Kumpf. Commensurate Registry and Chemisorption at a Hetero-organic Interface. Physical Review Letters, 2012; 108 (10) DOI: 10.1103/PhysRevLett.108.106103

Cite This Page:

Forschungszentrum Juelich. "Strong Grip: Unexpected interaction between organic semiconductors." ScienceDaily. ScienceDaily, 9 March 2012. <www.sciencedaily.com/releases/2012/03/120309103806.htm>.
Forschungszentrum Juelich. (2012, March 9). Strong Grip: Unexpected interaction between organic semiconductors. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2012/03/120309103806.htm
Forschungszentrum Juelich. "Strong Grip: Unexpected interaction between organic semiconductors." ScienceDaily. www.sciencedaily.com/releases/2012/03/120309103806.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) — Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) — TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) — Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) — When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins