Excitonic processes at organic heterojunctions

organic semiconductor;;heterojunction;;charge transfer exciton;;recombination;;

Understanding excitonic processes at organic heterojunctions is crucial for development of organic semiconductor devices. This article reviews recent research on excitonic physics that involve intermolecular charge transfer （CT） excitons, and progress on understanding relationships between various interface energy levels and key parameters governing various competing interface excitonic processes. These interface excitonic processes include radiative exciplex emission, nonradiative recombination, Auger electron emission, and CT exciton dissociation. This article also reviews various device applications involving interface CT excitons, such as organic light-emitting diodes （OLEDs）, organic photovoltaic cells, organic rectifying diodes, and ultralow-voltage Auger OLEDs.