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The use of bipolar materials as an active layer in polymeric solar cells can be an alternative to ‘bulk-heterojunctions’ composed of donor–acceptor blends. We have prepared two series of polyalkylthiophene copolymers having acceptor molecules covalently grafted to the backbone. The random copolymerization of thiophene monomers containing an acceptor moiety (anthraquinone or tetracyanoanthraquinodimethane) and 3-alkylthiophene monomers is a powerful strategy to tune both the donor–acceptor content and the electronic properties of the material. Emission measurements show for both copolymer series a photoinduced electron transfer from the donor π-conjugated backbone to the acceptor substituents, and this process can be modulated as a function of the chemical composition. [Copyright &y& Elsevier]

Since the discovery of the very fast photo-induced charge transfer between conducting polymers (as donors, D) and buckminsterfullerene (C60) (as acceptors, A), interpenetrating D/A networks have been proposed to improve the collection of free charges at the electrodes. The morphology of the D/A blend is of crucial importance and embedding the photoactive materials in a plasticing matrix was suggested as a method to overcome phase separation, and to favor homogeneity. In this contribution we report on a morphological characterization of three-component blends of the type poly(3-octylthiophene)/plasticizer/C60, with different plasticizing materials. The morphological investigation was done with transmission electron microscopy. The use of a conjugated thiophene-based plasticizer produces dispersed fullerene domains interpenetrated in the polymeric matrix. [Copyright &y& Elsevier]