Dispersive and nondispersive recombination of photoexcitations in disordered organic solids

We have analyzed both dispersive and nondispersive recombination of long-lived photoexcitations in disordered organic solids, and applied the results to cw photomodulation and millisecond transient photoinduced absorption in thin films of a novel copolymer of fluorene and an aminobenzene derivative. The results are explained using dispersive diffusion-controlled bimolecular recombination arising from an energetically random hopping system in which the energy of the hopping sites varies according to a Gaussian distribution.