Organic Light Emitting Diodes (OLED) have been providing a more attractive alternative to Light Emitting Diodes (LED) and Liquid Crystal Displays (LCDs) for some time now. OLED's ability to function without the need for a backlight makes them far more efficient than their LCD cousins and they are brighter than LEDs and don't need glass as a substrate like both LEDs and LCDs do.
However, OLEDs are not without their drawbacks; the two most notable problems involve exciton quenching and photon loss processes.
In an article over at Nanowerk recently reported work by researchers at the Institute of Nanostructured Materials (ISMN) in Bologna, Italy is described in which alternative planar light sources that combine the switching mechanism of a thin-film transistor and an electroluminescent device in the same architecture .
The research was initially reported in the May 2, 2010 online edition of Nature Materials. It is believed that the “Organic light-emitting transistors” (OLETs) could usher in a new era in organic optoelectronics. As quoted in Nanowerk’s exclusive interview with one of the researchers, "OLET is a new light-emission concept, providing planar light sources that can be easily integrated in substrates of different nature – silicon, glass, plastic, paper, etc. – using standard microelectronic techniques," says Michele Muccini "The focus of OLET development is the possibility to enable new display/light source technologies, and exploit a transport geometry to suppress the deleterious photon losses and exciton quenching mechanisms inherent in the OLED architecture." The nanotechnology bit of the device comes in its scale. The three organic layers of the device are 62nm thick and the gold contacts that serve as the source and drain are 50nm in size.
While the researchers concede that some technical improvements need to be made, such as reliability and lifetime-related issues, they believe the device provides a viable way of manufacturing organic light emitting devices with much improved performance over what is currently available.
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.