Small giants of light: OLEDs
Flexible screens may redefine the way things are displayed in the future. When
voltage is applied to semiconducting plastics, they being to emit light in
different colors. Such special polymers have one thing in common: Many double
bonds and aromatic rings, also known as conjugated pi-electron systems. These
conjugated materials used for organic light emitting diodes or PLEDs devices
because of their superior solubility, which makes them easy to deposit, and
their light emissions, which can be controlled through making substitutions.
For high efficiency and lifetime materials used for the three major functions
of an OLED: The hole transport the electron transport and the light emission.
An important step of the development of new materials is to improved the purity
of synthesized materials, rather than synthesizing more of them, Fraunhofer IAP
is concentrating on producing ultra-pure, defect free materials. In addition,
they are experimenting with using different combinations of hole transport and
electron transport materials to control the emissivity of the light emitting
diodes they make.
The Fraunhofer IAP team is working to adapt their process to serve an industrial
scale by developing low content displays with polymer materials, and finding
ways to effectively encapsulate the devices. They have partners in this effort,
notable the Polymer Surfaces Alliance, formed of seven Fraunhofer institutes.
In addition, representatives from display companies, equipment and material
suppliers, and colleagues from the Univesrity of Barunschweig are collaborating
in this project, which is being funded by the Federal Ministry for Education
and Research.