A combined experimental and simulation study on thickness dependence of the emission characteristics in multicolor single layer organic light-emitting diodes

The impact of the active layer thickness on the emission characteristics of multicolor single layer organic light-emitting diodes based on poly(9-vinylcarbazole) is examined by combining experimental results with model simulations. We compare experimental electroluminescence spectra with simulations using photon-emitting point dipoles and find a very good agreement. We also simulate the location of the recombination zone, considering that the emission probability distribution has a peak located 25 nm from the cathode, which decays exponentially above and below that point. Simulated radiation patterns show that microcavity effects dominate the thickness dependent emitting properties of these devices. (c) 2008 American Institute of Physics.