Transparent white OLEDs

White organic light-emitting diodes (WOLEDs) have been extensively studied for applications in flat panel displays and solid-state lighting. To date, much effort has been focused on developing high-performing phosphorescent WOLEDs for applications in lighting. This chapter discusses the development of high-performing transparent phosphorescent WOLEDs using a high-mobility electron transporting layer (ETL) along with a pair of Ag (10 nm)/MoO3 (2.5 nm)-modified indium tin oxide anode and a thin Al (1.5 nm)/Ag (15 nm)/index-matching-layer cathode. The hole-electron current balance in a dichromatic white transparent WOLED has been optimized through a combination of theoretical calculation and experimental optimization. A transparent WOLED with a visible-light transparency of <50%, a symmetrical bidirectional electroluminescence emission spectra with almost an identical power efficiency of 11 lmW-1 (measured at 100 cdm-2) and similar International Commission on Illumination coordinates from both sides has been demonstrated.