Organic light-emitting devices for illumination quality white light

Abstract

A method of generating white light by combining a blue organic light-emitting diode with a down-conversion phosphor system is presented. It is demonstrated that the use of the down-conversion phosphor system actually leads to an overall power efficiency increase, an effect attributed to the high quantum efficiency of phosphor materials and the presence of light scattering in the phosphor layers. It is also shown that this approach permits the generation of illumination quality white light over the full range of color temperatures required for lighting applications. For the model device demonstrated in this work, an overall electrical to optical power conversion efficiency of 1.3% was achieved at a brightness of 1080 ${\mathrm{cd/m}}^2.$