Morphology-dependent exciton diffusion length in PPE-PPVs thin films as revealed by a Forster mechanism based-study
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The effect of thickness and alkoxy side chains on the optical properties of poly(p-phenyleneethynylene)-alt-poly(p-phenylenevinylene)s (PPE?PPVs) have been investigated in parallel fashion. A Forster energy transfer mechanism has been invoked in order to infer the exciton diffusion length (LD). The latter parameter has been determined for six differently alkoxy-substituted PPE-PPVs for different thicknesses. The dependence of LD upon the donor-acceptor (D-A) distance (d) has been assessed as well. The results reveal an increase of LD up to 25 nm, with the increase of the sample thickness and side chain length.