Printable organic LED technology could be used to enable large-scale patterned and flexible light-emitting surfaces for advertising displays, as well as transparent smart surfaces to be attached to windows or packaging. Developed by VTT Technical Research Centre of Finland Ltd., the method allows printing of OLEDs not only onto glass or steel surfaces but also onto flexible plastic films, enabling significantly larger light surfaces and expanding the usage possibilities of the technology. A printable organic LED film developed by VTT. Courtesy of Juha Sarkkinen. Manufactured using the gravure and screen printing methods, the OLED light surfaces are around 0.2 mm thick, and include electrodes and light-emitting polymer layers measuring up to a few hundred nanometers. At this point, VTT's plastic OLED film will only emit light for around a year because light-emitting polymer materials are susceptible to oxygen and moisture. In the future, the film’s lifespan will increase as the development of screen protectors continues and the film’s application possibilities grow. “The plastic film is optimally suited to advertising campaigns, in which large light-emitting surfaces can be used to draw significantly more attention than can be gained through mere printed graphics or e-ink-type black-and-white displays that do not emit light,” said VTT Head of Research Area Raimo Korhonen. It is also possible to use OLEDs as wireless data transmitters, which the company said opens up new possibilities for using printed light surfaces in Internet-of-Things applications. For more information, visit www.vttresearch.com.