Optical properties of single carrier polymer diodes under high electrical injection

We present measurements of the modulation of the near absorption edge optic al properties of single carrier diodes made from a soluble poly(p-phenylene vinylene) derivative. Pulsed electrical excitation was used to acquire the optical characteristics for average injected charge densities up to 10(18) cm(-3). For injected carrier densities below 5x10(17) cm(-3), the modulati on of the optical properties are dominated by electroabsorption effects; at higher densities, the effects of the injected charge predominate. We find that there is no significant absorption by the injected charge below the op tical absorption threshold and that there is substantial bleaching of the l owest energy optical transitions at high carrier density. These results imp ly that charge carrier absorption in this polymer does not limit the perfor mance of organic light-emitting diodes and diode lasers. (C) 2001 American Institute of Physics.