No abstract

No abstract

The concept of an additional capping layer, which is deposited onto the semitransparent top contact, is applied to minimize microcavity effects for white light emission from top-emitting organic light emitting devices (OLEDs). The influence on the optical properties of such devices with silver as top electrode material is discussed using an analytical method and numerical simulations. The results of the theoretical findings are experimentally verified for inverted top emitting devices on opaque substrates, showing broad spectral bandwidth and angle-independent color coordinates.

We directly follow the evolution of the absorption spectrum from a single molecule to a dimer and further to a one-dimensional molecular stack: We determine the optical absorption properties of ordered monolayer to multilayer films of PTCDA (3,4,9,10-perylenetetracarboxylic dianhydride) on muscovite mica(0001) surfaces by in situ differential reflectance spectroscopy. The data clearly show the transition from the single molecule to a dimer spectrum, followed by the exciton delocalization to a molecular crystal exciton. The accompanying spectral shifts compare favorably with recent model concepts.

No abstract