USING SELK-ASSEMBLED MONOLAYKRS TO MODIFY ELECTRODE INTERFACES IN ORGANIC LIGHT-EMITTING DIODES

摘要

Organic light-emitting diodes (OLEDs)| 11, including those where the active layer is a conjugated polymer (PLEDs)|2J. are under intensive study because of their potential as light sources, indicators and flat panel displays.|3| Tneir basic structure is a sandwich of one or more organic-layers between two electrodes, one of which, the cathode, is chosen to inject electrons while the other, the anode, is selected for optimal hole injection, When u current is passed through the device, electrons from the cathode combine with holes from the anode to create molecular excitations (singlet excitons) which relax to the ground state with some probability of radiative emission. The efficiency of light output depends on many factors, including the voltage (or electric field) required to inject charge at the electrodes and drive it through the bulk of the organic layers, the balance between electron and hole current and the fluorescent yield from each recombination event. In this paper we address the. issue of charge injection.