Novel porphyrin-containing regioregular poly(alkylthiophene) copolymers tested as polymeric solar cells

Regioregular polyalkylthiophene copolymers were prepared by oxidative copolymerization of known amounts of brominated alkylthiophene monomers possessing or not a reactive bromide group linked at the end of the alkyl chain. Subsequent post-polymerization functionalization with tetraphenylporphyrin led to products with differing dye content in the side chain. Due to their chemical structure, the copolymeric precursors, as well as the porphyrin functionalized derivatives, were fully soluble in common organic solvents and could be used as active layers, in combination with PCBM, for the preparation of polymeric solar cells (PSC) with bulk heterojunction architecture. The power conversion efficiency of the cells containing porphyrin resulted remarkably higher with respect to the cells containing the precursor bromoalkyl moiety in the side chain and one order of magnitude higher with respect to similar previously investigated PSC produced with lower porphyrin content.