Photoinduced electron transfer in [10]CPP⊃C60 oligomers with stable and well-defined supramolecular structures

Recent synthesis of a new type of polymer containing conjugated cycloparaphenylene (CPP) macrocycles interconnected by a linear conjugated backbone opens up great potential of cyclic pi-conjugated materials in organic photovoltaics. In this work, I report a theoretical study of the ground and excited state properties of such polymers and investigate an effect of inclusion of fullerene molecules into polymer chains. MD simulations reveal that oligomers ([10]CPP_Fused superset of C-60)(24) and ([10]CPP_Fused superset of C-60)(32) with pi-extended CPPs tend to form stable, helix-like structures. I show that photoinduced electron transfer from the CPP-based polymer to C-60 fullerene is favorable and occurs on a nanosecond time scale. The hole- and excess-electron transfer rates are found to be significantly higher than the corresponding charge recombination rates.