Excitonic Shockley-Read-Hall recombination in organic semiconductors

Trap-mediated recombination influences the performance of a wide range of organic semiconductor devices, but it has so far been unclear how the well-known Shockley-Read-Hall (SRH) recombination rate expression extends to this class of materials. This study formalizes SRH recombination for organic semiconductors and shows how it is modified to account for the finite lifetime of the exciton intermediate state involved in their recombination process. This result is important in organic light-emitting diodes, where it identifies the relative host and dopant energetics in the emissive layer, which are needed to achieve ultralow voltage operation.