ABSTRACT
To be widely adopted, electroluminescent devices must not only match the color purity and long-term stability of competing technologies, but they must also provide a significant
advantage in efficiency, especially in low-power, portable applications. In this chapter, we examine the fundamental limits to the performance of organic light-emitting diodes (OLEDs), and concentrate on methods to improve their efficiencies significantly. We first explain the various factors that comprise the power efficiency of an OLED. Then electrophosphorescence, a method for significantly improving the efficiency of organic devices, is described and characterized. Finally, the status of electrophosphorescent technology is discussed as of writing in 2002; we concentrate on three device criteria: power efficiency, emission color purity, and stability.
6.2 POWER EFFICIENCY
