New donor-acceptor materials based on random polynorbornenes bearing pendant phthalocyanine and fullerene units

New donor-acceptor materials based on a polynorbornene framework to which both phthalocyanine and C-60 electroactive pendant units are randomly attached have been prepared in good yield by ring-opening-metathesis polymerization (ROMP) in the presence of a Grubbs catalyst. A structurally related phthalocyanine homopolymer was also synthesized for comparison. A remarkable fluorescence quenching was observed in the homopolymer and accounts for Pc center dot center dot center dot Pc interactions along the polymeric framework. As expected, the fluorescence quenching increases in the case of the polynorbornenes containing both Pc and C-60 units owing to photoinduced electron transfer, which was further confirmed by transient absorption spectroscopy. Finally, preliminary solar cell devices made of one of the copolymers were constructed.