Abstract
Since the first report of efficient and practical organic light-emitting devices (OLEDs) in 1987 by Tang and VanSlyke [1], OLEDs have been the subject of intensive studies for flat-panel displays and lighting applications due to several advantages such as high efficiency, wide viewing angle, fast response, and potential low cost. In addition, their low processing temperatures and thereby versatility in substrates make them suitable for some novel applications such as flexible displays and lighting. Over the last two decades, OLED technology has made rapid progress, and several types of OLED displays have been manufactured and commercialized. With the continuous improvements in the efficiencies of OLEDs and white-emitting OLEDs, the application of OLEDs in lighting is also becoming realistic.