Independently controllable stacked OLEDs with high efficiency by using semitransparent Al/WO3/Ag intermediate connecting layer

A high efficiency organic light-emitting device (OLED) has been fabricated by using a vertical stack of two OLED units connected by Al/WO3/Ag. In the stacked OLEDs, each unit can be independently biased. It is found that the introduction of WO3 between Al and Ag enhances the electroluminescent (EL) efficiency by 3.7 cd A-1 for the top emissive unit. Meanwhile, the EL efficiency of the stacked OLED with the Al/WO 3/Ag interconnecting electrode is improved by 6 cd A-1 with respect to the case of using Al/Ag as the connecting electrode. Our results indicate that Al/WO3/Ag is an excellent kind of connecting structure for the fabrication of independently controlled high efficiency stacked OLEDs. © 2008 IOP Publishing Ltd.link_to_subscribed_fulltex