Optical properties of single carrier polymer diodes under high electrical injection

Abstract

We present measurements of the modulation of the near absorption edge optical 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 1018 cm−3. For injected carrier densities below 5×1017 cm−3, the modulation 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 optical absorption threshold and that there is substantial bleaching of the lowest energy optical transitions at high carrier density. These results imply that charge carrier absorption in this polymer does not limit the performance of organic light-emitting diodes and diode lasers.