Externally Initiated Regioregular P3HT with Controlled Molecular Weight and Narrow Polydispersity

摘要

Poly(3-hexylthiophene) (P3HT) remains the most commonly used polymer in organic photovoltaics because of its desirable electronic properties. Both the Yokozawa and McCullough groups have developed methods for the synthesis of highly regioregular P3HT with controlled molecular weights and narrow molecular weight distributions using the 1,3-bis(diphenylphosphino)propanenickel(II) chloride [NiCl_2(dppp)]-catalyzed polymerization of Grignard-type monomers. The polymerization control is thought to originate from either intramolecular transfer of the Ni catalyst or an associated pair formed by the growing polymer chain and the Ni catalyst. The drawback of this synthetic methodology is that it is not possible to initiate the polymerization from an external moiety, as has been demonstrated for the chain-growth polymerization of polyfluorene.