M. Gross et al., Dependence of the hole-injection barrier on the hole conductor in organic light emitting diodes based on composites, SYNTH METAL, 102(1-3), 1999, pp. 1147-1148
Organic light-emitting diodes based on composites using different hole cond
uctors were fabricated and characterized. In these devices the current flux
is limited by the injection of holes into the semi-conducting polymer laye
r through tunneling. The data were evaluated using the common Fowler-Nordhe
im formalism. The barrier height was found to depend linearly on the oxidat
ion potential of the hole conductor, but unexpectedly the slope is only 0.5
5 +/- 0.1. This result is explained by the non-polar nature of the internal
interface between ITO and the conductive layer.