The new technology, which combines organic and traditional solid-state light emitting features, has the potential to produce much purer colors and use much less electricity than existing LEDs. "One of the goals is to demonstrate a display that is stable, simple to produce, flat, high-resolution and that uses minimal power," researcher Vladimir Bulovic said.
The displays are based around quantum dots--microscopic holes in a crystalline structure that are designed to hold a handful of electrons. By moving electrons into and out of these dots light is produced, and by changing the size and spacing of the dots, a wide variety of colors can be produced.
Other forms of lighting depend on the natural configuration of compounds, and thus have a much more limited range of colors. Practically speaking, a layer of quantum dots is sandwiched between two layers of other compounds, one electron-rich and one electron-poor. The researchers use plastic semiconductors for these outer layers--very fashionable new materials that many expect will eventually replace LCDs.
MIT says that the major advance with this technology, called Quantum Dot Organic LED, or QD-OLED, is that the filling in the sandwich is just one quantum dot thick. This has the potential to allow 100 percent of the electrons moved into the holes to produce light, compared to a maximum efficiency in other systems of around 30 percent and an actual efficiency that can struggle to beat 5 percent. Previous QD-OLEDs had layers of 10 to 20 quantum dots; the single-dot layer is just three nanometers across.
In addition to being used for extraordinarily thin, bright flat-panel displays, MIT said, the QD-OLEDs may be used to create very stable light for scientific experiments and to miniaturize scientific equipment.
