Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Stanford-led research helps overcome barrier for organic electronics

Engineered organic semiconductor crystals such as these are used to study the effects of current flow in thin film transistors that could be useful in digital displays and flexible electronics.
Engineered organic semiconductor crystals such as these are used to study the effects of current flow in thin film transistors that could be useful in digital displays and flexible electronics.

Abstract:
Electronic devices can't work well unless all of the transistors, or switches, within them allow electrical current to flow easily when they are turned on. A team of engineers has determined why some transistors made of organic crystals don't perform well, yielding ideas about how to make them work better.

Stanford-led research helps overcome barrier for organic electronics

Stanford, CA | Posted on November 16th, 2009

Providing insight into a frustrating inconsistency in the performance of electronics made with organic materials, Stanford researchers have shown that the way boundaries between individual crystals in a film are aligned can make a 70-fold difference in how easily current, or electrical charges, can move through transistors.

The research, which could help engineers design better digital displays and other devices, was published online Nov. 8 in the journal Nature Materials.

Organic semiconductors have a lot to offer in electronics. They are cheap and flexible, and the production process is much simpler than for traditional silicon chips. Applications such as computer display screens, digital signs or magazines made of "electronic paper" have been possibilities for more than a decade, but their full potential seems always just around the corner. A persistent problem is that performance from transistor to transistor varies much more than can be allowed in commercially viable devices.

"You can make a single device that has high 'charge mobility,' but you really need to make thousands of them," said Alberto Salleo, an assistant professor of materials science and engineering at Stanford and a senior co-author of the paper. "Most research groups report a high variation in that mobility. What we did here is try to understand what causes the variation."

Systematic study

Salleo's group led a multidisciplinary team of researchers in making a systematic study of a likely culprit of the inconsistent transistor performance in polycrystalline devices: the "grain" boundaries between crystals. It turns out that the differences in boundary alignment can make the path that electric charges must follow through a transistor look more like a disjointed slog through airport security than a sprinter's dash.

To examine the role that boundary alignment plays, the paper's lead author, graduate student Jonathan Rivnay, grew crystals of an organic semiconductor called PDI8-CN2, synthesized at Northwestern University and Polyera Corp., an organic electronics company, using a process that ensures consistent alignment from crystal to crystal in a particular direction.

He then made transistors in which charges could flow through molecules that were well aligned with each other, and others where the molecules were misaligned across the grain boundaries. The first kind of transistors performed far better. He went further to link the properties of these boundaries to the molecular packing in the crystals.

In addition to the team's direct electrical measurements, the researchers employed information from extensive theoretical calculations, made by co-author John E. Northrup at Xerox Palo Alto Research Center, and with X-ray analysis headed by co-author Michael Toney at the Stanford Synchrotron Radiation Lightsource.

Could influence future production

Rivnay said the team's work could strongly influence how organic crystal electronics are made in the future.

"The problem of understanding defects in organic electronic materials including grain boundaries is very important for any device application," Rivnay said. "By better understanding what goes on at these boundaries, and how detrimental they are, improvements can be made at the chemistry end as well as at the design and fabrication end of the process. This way devices can be more reproducible and better performing."

Other authors were Stanford graduate students Leslie Jimison in Materials Science and Engineering and Rodrigo Noriega in Applied Physics; Northwestern University chemist Tobin Marks; Polyera Corp. researcher Shaofeng Lu; and Northwestern faculty member and Polyera Chief Technology Officer Antonio Facchetti. Funding came from multiple U.S. federal institutions, including the departments of Defense and Energy and the National Science Foundation, as well as the King Abdullah University of Science and Technology in Saudi Arabia.

####

About Stanford University
Located between San Francisco and San Jose in the heart of Silicon Valley, Stanford University is recognized as one of the world's leading research and teaching institutions.

For more information, please click here

Contacts:
David Orenstein
School of Engineering
(650) 736-2245

Copyright © Stanford University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Arrowhead Receives Regulatory Clearance to Begin Phase 1 Study of ARO-AAT for Treatment of Alpha-1 Liver Disease February 22nd, 2018

MEMS chips get metatlenses: Combining metasurface lenses with MEMS technology could add high-speed scanning and enhance focusing capability of optical systems February 21st, 2018

Atomic structure of ultrasound material not what anyone expected February 21st, 2018

Oxford Instruments announces Dr Kate Ross as winner of the 2018 Lee Osheroff Richardson Science Prize for North and South America February 20th, 2018

Possible Futures

MEMS chips get metatlenses: Combining metasurface lenses with MEMS technology could add high-speed scanning and enhance focusing capability of optical systems February 21st, 2018

Atomic structure of ultrasound material not what anyone expected February 21st, 2018

Computers aid discovery of new, inexpensive material to make LEDs with high color quality February 20th, 2018

Photonic chip guides single photons, even when there are bends in the road February 16th, 2018

Chip Technology

Photonic chip guides single photons, even when there are bends in the road February 16th, 2018

Graphene on toast, anyone? Rice University scientists create patterned graphene onto food, paper, cloth, cardboard February 13th, 2018

Liquid crystal molecules form nano rings: Quantized self-assembly enables design of materials with novel properties February 7th, 2018

Nanometrics Selected for Fab-Wide Process Control Metrology by Domestic China 3D-NAND Manufacturer: Latest Fab Win Includes Comprehensive Suite for Substrate, Thin Film and Critical Dimension Metrology February 7th, 2018

Nanoelectronics

Graphene on toast, anyone? Rice University scientists create patterned graphene onto food, paper, cloth, cardboard February 13th, 2018

Vanadium dioxyde: A revolutionary material for tomorrow's electronics: Phase-chance switch can now be performed at higher temperatures February 5th, 2018

Measuring the temperature of two-dimensional materials at the atomic level February 3rd, 2018

Viewing atomic structures of dopant atoms in 3-D relating to electrical activity in a semiconductor December 28th, 2017

Announcements

Arrowhead Receives Regulatory Clearance to Begin Phase 1 Study of ARO-AAT for Treatment of Alpha-1 Liver Disease February 22nd, 2018

MEMS chips get metatlenses: Combining metasurface lenses with MEMS technology could add high-speed scanning and enhance focusing capability of optical systems February 21st, 2018

Atomic structure of ultrasound material not what anyone expected February 21st, 2018

Oxford Instruments announces Dr Kate Ross as winner of the 2018 Lee Osheroff Richardson Science Prize for North and South America February 20th, 2018

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project