Novel High Efficiency High CRI Phosphorescent OLED Lighting Containing Two Broad Emitters

In 2001, lighting was estimated to have consumed 8.2 quads (approximately 762 TWh), or about 22% of the total electricity generated in the U.S. New high-efficiency, solid-state light sources, such as light emitting diodes (LEDs) and organic LEDs (OLEDs), are needed to reduce the ever increasing demand for energy. An OLED is potentially a cost effective, diffuse light source that would compete directly with conventional incandescent light sources. However, improvements in the overall efficiency of OLEDs are still required before they can achieve their cost and performance goals ¿ $3 per 1000 lumens and 90 lumens per watt, respectively ¿ and become commercially viable products. This project will demonstrate a path to novel, low-cost, high-efficiency white lighting using a simple OLED device structure that employs only two molecularly emissive phosphorescent dopants. Phase I will use the two dopants to enhance higher-order, phosphorescent-emission vibronic peaks within the OLED microcavity, thereby achieving a white OLED (WOLED) with color rendering index (CRI) greater than 75 and efficacy of 35 lm/W at 800 cd/m2. The WOLED will be engineered to provide stable chromaticity as a function of drive conditions. The specific goal will be a WOLED with less than a 10% change in chromaticity within the luminance range of 100-to-2,000 cd/m2. Commercial Applications and other Benefits as described by the awardee: High-efficiency, white phosphorescent, OLED lighting devices, containing only two emissive dopants, would simplify and lower the manufacturing cost of OLED lighting, making OLEDs even more efficient and cost-effective in general lighting applications.