Secondary ion mass spectroscopy study of failure mechanism in organic light emitting devices

Secondary ion mass spectroscopy is used to examine the dark, non-emissive defects on the organic light emitting device. Boundary movements are originated from electrode imperfection. Due to flexibility and movability of polymer layer, distribution variations and a more severe indium and calcium overlapping are detected in dark spot defect area. Boundary movements are not in good agreement between different layers. Interfaces became undulate. The closeness and proximity between the In sharp spikes and cathode metal protrusion leads to the initial point of dark spot. We demonstrate that the presence of cathode imperfection and interface roughness of different layers correlated to the device dark spot formation.