A self-powered display—
thin, flexible, and durable
enough to be incorporated into clothing—is one of
the goals of a $1.7 million
international research
project that aims to bring organic light-emitting diodes (OLEDs) to the mass
market. The research consortium, known
as Modecom (for Modeling Electroactive
Conjugated Materials at the Multiscale),
includes 13 engineering teams from
nine universities and two companies.
Over the next three years, the
researchers plan to improve the science
behind OLEDs, making them powerful, reliable, and efficient enough to be used in an
array of business and consumer products.
OLEDs are already a part of some portable
gadgets, such as mobile phones and MP3
players. But Modecom wants to make it
practical for the devices to be used in
large-screen applications, such as televisions and computer displays.
Increasing the size of OLEDs would
also open the door to cutting-edge applications, like clothing-based displays,
next-generation lighting systems, and
portable solar power panels, explains
project coordinator Alison Walker, a senior lecturer in the physics department at
England's University of Bath (Fig. 1).
The biggest problem with current
OLEDs is reliability. Gadget-sized OLEDs
work well enough, but larger versions—
designed for use in TVs and desktop displays—tend to fail quickly, often within months. Walker says the consortium is
aiming for an improved understanding of
how OLEDs work, which will aid in the
design of longer lasting OLEDs.
"We are trying to link how they are
made with how they perform, a very ambitious task but one in which we expect at
least partial success," she says.
Modecom is focusing on two specific
types of OLEDs: small molecule devices,
developed in the U.S. and Japan by firms
including DuPont subsidiary Uniax, and
polymer OLEDs (P-OLEDs), pioneered in
Europe by Cambridge Display Technology,
a Modecom partner, Philips, and several
other firms (Fig. 2).
"Small molecule OLED devices are further \[along\] in development, but are more
expensive to make as they can not be
made by inkjet printing," Walker says. She
also predicts that large OLEDs will reach
the market in less than five years.
At that point, she expects clothing vendors to weave OLED strips, running off of
solar power, into garments. The strips could change color at the press of button
or be used to display electronic messages. "They are cheap to make, are flexible, are bright," Walker says. "Polymers
are inherently compatible with clothing,
unlike their competitors in the display
market such as liquid crystal displays."
Walker expects OLEDs to begin replacing incandescent, fluorescent, and even
conventional LED lights within the same
five years and to someday become the
leading artificial lighting technology.
Walker notes that Modecom's molecular- and device-level research will also
help expand the understanding of polymer materials used in plastic electronics
for applications such as electronic paper
and intelligent labels (Fig. 3). "OLEDs
would not have advanced to their present stage, nor would have any hope of
getting further, unless the science is
understood," she says.
John Edwards
Modecom
www.modecom-euproject.org
