Solid-State Lighting Using Side-by-Side White Phosphorescent Organic Light-Emitting Diodes
Claire Arneson, Xinjing Huang, Stephen R. Forrest
Abstract
White organic light-emitting diodes (WOLEDs) have become increasingly popular for use in solid-state illumination, where diffuse, large area light sources that achieve a high color rendering index and luminous power efficiency are desirable. Color-tunable emission, where the light source combines emission from multiple, separately addressed color elements, is conveniently provided by WOLEDs for the purpose of adapting the lighting source to a particular illumination requirement. In this work, we demonstrate a method for side-by-side positioning of monochromatic blue and yellow phosphorescent OLED stripes that are combined to create tunable white light, using a high-resolution mechanical peel-off patterning method. We achieve a peak luminous power efficiency of 17.1 ± 0.3 lm W –1 and an external quantum efficiency of 11.8 ± 0.2% and demonstrate color tunability of the 1960 Commission Internationale d’Eclairage chromaticity coordinates from ( u,v ) = (0.33,0.36) to (0.12,0.32). This corresponds to a tuning range of the color rendering index from 74 ± 1 to 86 ± 1 and the correlated color temperature from 2000 to 8000 ± 500 K. Due to the nondestructive nature of the peel-off technique, patterned devices exhibit a lifetime comparable to conventional, shadow mask-patterned devices.