Archive notice: This article was originally published on August 24, 2009. Links and embedded videos are preserved as part of the historical record.
An international research team led by Americans has developed a new approach that enables ultrathin, extremely small inorganic LEDs. These can be assembled into lighting or display systems that are almost transparent or very flexible. Until now, this had been reserved for organic LEDs (OLEDs). “Our aim is to combine some advantages of inorganic LEDs with the scalability, easy processing and resolution of OLEDs,” says John Rogers, Professor of Materials Science and Engineering at the University of Illinois.
According to the University of Illinois, inorganic LEDs are brighter, more stable and longer-lasting than OLEDs. The latter, however, have the advantage of being processable in flexible, dense arrangements and through printing methods. The new approach promises to unite the advantages of both worlds. “By printing large arrays of ultrathin, ultrasmall inorganic LEDs and connecting them using thin-film processing, we can create general lighting and HD display systems that could not be manufactured from inorganic LEDs using conventional methods,” Rogers says. To achieve this, the team made inorganic LEDs 100 times smaller than usual and developed a special printing process that allows them to be applied to rigid substrates such as glass, as well as flexible or stretchable ones such as rubber. The LEDs could generate enough light to be placed at large intervals, which could also enable practically transparent displays.
“That sounds like a really promising approach,” confirms Bert Fischer, research associate at the Fraunhofer Institute for Applied Polymer Research IAP. Work there focuses on the application of OLEDs, which are already used for flexible electronics. In such application areas, OLEDs could gain inorganic competition through the new manufacturing method. Fischer is eager to see whether the new approach can deliver in practice what it promises. He thinks it possible that the tiny points of light with relatively large dark surrounding areas could ultimately result in displays that appear comparatively pixelated. Even if that were initially the case, the new technology could of course still develop accordingly.
