Incandescent light bulbs are energy hogs, but many people prefer them for the cozy quality of light they emit. Scientists from Dresden University of Technology in Germany have set out to build energy efficient organic LED (OLED) lights that could rival incandescent bulbs in white-light color quality. OLEDs consist of many layers of organic materials with different electrical properties.
In the future, organic semiconductors can replace crystalline materials like silicium that are used frequently today in many electronic applications, opening a whole new field of possibilities to use electronics. Their advantage: It is relatively simple and cost-efficient to process them into electronic products like transistors, luminous diodes or solar cells because they are a thin, flexible, transparent foil of almost any desired size.
Before now, a drawback of synthetic electronics was their low efficiency. In addition, they didn’t last long enough for commercial use. The scientists from Dresden greatly improved the efficiency of organic lamps and reflectors by „studding“ or doping the synthetic materials in them with certain foreign substances. They designed organic luminous diodes (OLED) with a higher light output than fluorescent tubes that will in the future play a big role in the lighting of offices and living spaces.
Among the realistic visions of the nominees are large-scale luminous sources that can change color and be used like wallpaper. Transparent, thin solar cells can stick to cars or clothing and produce electricity from sunlight in the future. For the production of those materials, the scientists created a first coil-to-coil construction that prints organic electronic components onto a thin layer, similar to the printing of a newspaper. The applications are currently being realized in two spin-off enterprises.
Article: "Organic LEDs for Lighting: High Color Quality by Controlling Energy Transfer Processes in Host-Guest-Sytems" is accepted for publication in the Journal of Applied Physics.
Authors: Caroline Weichsel (1), Sebastian Reineke (1), Mauro Furno (1), Björn Lüssem (1), and Karl Leo (1).
(1) Institut für Angewandte Photophysik, Technische Universität Dresden, Germany
Before now, a drawback of synthetic electronics was their low efficiency. In addition, they didn’t last long enough for commercial use. The scientists from Dresden greatly improved the efficiency of organic lamps and reflectors by „studding“ or doping the synthetic materials in them with certain foreign substances. They designed organic luminous diodes (OLED) with a higher light output than fluorescent tubes that will in the future play a big role in the lighting of offices and living spaces.
Among the realistic visions of the nominees are large-scale luminous sources that can change color and be used like wallpaper. Transparent, thin solar cells can stick to cars or clothing and produce electricity from sunlight in the future. For the production of those materials, the scientists created a first coil-to-coil construction that prints organic electronic components onto a thin layer, similar to the printing of a newspaper. The applications are currently being realized in two spin-off enterprises.
Credit: Dresden University of Technology
Excited electrons move through the materials and when the electrons are reunited with positive "holes," they emit electromagnetic radiation in the form of visible light. To build their white light OLED, the researchers used four separate emitter layers: blue, green, yellow, and red. The different colors are combined to cover all parts of the visible spectrum.
Through a detailed study of the movement of electrons through the OLED, the scientists were able to tune the color and quality of the light by adjusting the height of the layers. The final OLED, described in the AIP's Journal of Applied Physics, casts a color of light very near to warm white point A, a standard measure of the white light spectrum reached by some incandescent bulbs. The OLED also has high color stability, meaning the light can be dimmed without noticeably altering its quality.
Contacts and sources:
Catherine Meyers
American Institute of Physics
Contacts and sources:
Catherine Meyers
American Institute of Physics
Article: "Organic LEDs for Lighting: High Color Quality by Controlling Energy Transfer Processes in Host-Guest-Sytems" is accepted for publication in the Journal of Applied Physics.
Authors: Caroline Weichsel (1), Sebastian Reineke (1), Mauro Furno (1), Björn Lüssem (1), and Karl Leo (1).
(1) Institut für Angewandte Photophysik, Technische Universität Dresden, Germany
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