Alek Dediu on Spin Routes in Organic Semiconductors
Fast Breaking Commentary, October 2010
|
Article: Spin routes in organic semiconductors
Authors: Dediu, VA;Hueso, LE;Bergenti,
I;Taliani, C |
Alek Dediu talks with ScienceWatch.com and answers a few questions about this month's Fast Breaking Paper paper in the field of Materials Science.
Why do you think your paper is highly
cited?
The main reason, in my opinion, is that the paper reviews the new and exciting field of organic spintronics. Nowadays, information and communication technology is challenged by the need to develop and pursue new paradigms for the future devices. The race towards miniaturization within the MOSFET/CMOS approach cannot be too far off. Industrial experts estimate 2020 as a kind of threshold point, when new materials and new concepts are expected to massively enter the market.
The scientific community is thus paying a serious attention and is deeply supporting the fields which propose new solutions in this direction. Organic spintronics is indeed among most challenging and promising branches in this contest.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
The paper is a review. But it not only describes passively the achievements—the paper also traces future strategic lines and proposes a kind of priority plans. For example, it places the hybrid (organic-inorganic) interfaces among highest priorities, and, indeed, in the year immediately after the paper was published, a few significant results were achieved along this line (Barraud et al., Nature Physics 6: 615, 2010; Y. Zhan et al., Advanced Materials 21: 1, 2009).
Would you summarize the significance of your paper
in layman's terms?
"Organic semiconductors and the interfaces between these materials and various metals feature properties radically different from those known in the inorganic material field."
To quote from the paper itself, organic semiconductors (OSC) research over the past decades has made continuous and impressive progress. The greatest success has been undoubtedly achieved in the optoelectronics field, where display products based on hybrid light-emitting diodes with organic emitter (OLEDs) have become available to consumers, and organic photovoltaic devices are challenging existing commercial applications.
These accomplishments generate a strong demand for other mainstream products based on new hybrid organic-inorganic devices. Considerable improvements have already been achieved in organic field-effect transistors (OFETs), while organic electric memories for data storage applications are currently attracting both fundamental research and applications.
Spintronics, on the other hand, tends to operate with the spin of the electron (intrinsic electron magnetic moment) rather than its charge—the latter is operated in the standard electronics. This promises intriguing new storage and processing abilities and generally requires lower operation energy.
Organic semiconductors are materials which maintain nearly invariable properties when (naturally) down-scaled to a molecule—a 1nm size, an order of magnitude below recent miniaturization capabilities. Summarizing, organic spintronics utilizes most down-scalable materials addressing them in a most gentle and energy consuming approach.
How did you become involved in this research, and
how would you describe the particular challenges, setbacks, and
successes that you've encountered along the way?
Carlo Taliani and I pioneered this field back in 2000, when we patented this discovery and published a paper later in 2002. Actually we were mainly willing to modify the behavior of the OLEDs, where the spin selection rules are rather stringent. Instead, we revealed a significant magnetoresistance, which is now at the center of organic spintronic research lines.
Where do you see your research leading in the
future?
Organic semiconductors and the interfaces between these materials and various metals feature properties radically different from those known in the inorganic material field. These properties, in my opinion, will promote radically new device paradigms. For example, the multifunctionality—a possibility to write-read the information by using more than one external stimuli (magnetic field, electric field, optical excitation, etc.)—is intrinsically characteristic for organic semiconductors.
Our group has recently demonstrated the coexistence in the same device of an electrically driven non-volatile resistance switching and magnetic switching. This proposes a simple device with an intriguing combination of two 0-1 logic gates.
Do you foresee any social or political
implications for your research?
I really hope some new applications based on the described approaches will
lead to new wellness levels in terms of an ecologically careful path. Such
an appealing application of the flexible electronics involving organic
semiconductors is the electronic paper. It requires, of course, reading
light-emitting outputs, but it also requires processing and storage
circuits, and spintronics will be able to offer many different solutions to
it. If really successful, this application would make our lives more
comfortable, and hopefully will save an enormous number of
trees.
Dr. Valentin Alek Dediu
Spintronic Devices Group
Institute of Nanostructured Materials ISMN-CNR
Bologna, Italy
KEYWORDS: MAGNETIC TUNNEL-JUNCTIONS; LIGHT-EMITTING-DIODES; ROOM-TEMPERATURE; GIANT MAGNETORESISTANCE; MOLECULAR SPINTRONICS; POLARIZED INJECTION; SANDWICH DEVICES; CHARGE INJECTION; TRANSPORT; VALVE.