Modeling the carrier density in the exciton formation zone of organic light-emitting diode under high current injection

The carrier density in exciton formation zone is the electrical parameter most relevant to the stability of organic light-emitting diode: the decrease of carrier density improves the device stability. Here, based on the general mode of carrier device lifetimes, the carrier densities in the exciton formation zone of organic light-emitting diode have been calculated at current densities (J) >= 2.0 kA cm(-2). With J increasing, the carrier density increases accordingly. At a given J, the carrier density decreases with the emissive layer's thickness increasing, but increases with the emissive layer's charge carrier mobilities. The increase of the energetic disorder of emissive layer leads to a marked decrease of carrier density. Increasing the hole (electron) mobility of hole (electron) transport layer helps reduce carrier density. The current research is believed very beneficial to the development of electrically pumped organic lasers.