Dresden 2006 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 23: POSTER Functional Organic Thin Films

CPP 23.37: Poster

Thursday, March 30, 2006, 17:00–19:00, P2

Optical Studies on the Leaky Mode Emission of Organic Light Emitting Devices — •Nils A. Reinke, Michael Hutzel, Johannes Höchtl, Claudia Ackermann, and Wolfgang Brütting — Experimental Physics IV, Institute of Physics, University of Augsburg, Germany

In bottom emitting OLEDs, usually a large fraction of light generated in the organic multilayer stack is wave-guided inside the substrate and is either reabsorbed by the organic layers or edge emitted. Thus light propagating at angles larger than the critical angle for total internal reflection (≈ 42^∘) is not accessible. These losses can be decreased by coupling the substrate to an optical element. This allows observation of light emission over all angles and increases the emission intensity of ITO-based OLEDs in forward direction by 50% with respect to the freestanding device.

In order to enhance the coupling of the guided leaky modes to the adjacent optical element and therefore to external modes, we utilized a micorcavity structure by replacing the ITO anode by a thin metal film. In this configuration, the metal film enhances the gain of guided leaky modes whereas the contribution of non-guided modes is suppressed. These devices show highly polarised emission (TE mode) and tuneable emission wavelength over a wide angular range. The observed behaviour can be predicted quantitatively by simulations which are based on the transfer matrix formalism.