Degradation of organic light-emitting diode

Ultra high vacuum operated prototypical organic light emitting diodes have been investigated by using chemically sensitive x-ray photoelectron microscopy. The mechanism of dark spot formation and degradation of organic light emitting devices have been imaged and spectroscopically measured. The morphology and the chemical composition of the Al cathode reveal the formation of volcano like defects as a result of local micro-explosions. The chemical maps and micro-spot spectra identify a release of volatile In-, Sn- and C-containing species, including metallic In, supporting the evidence that the degradation process is driven by local decomposition of the ITO/organic interface.