Atomic Force Microscopy and Grazing Incidence Small Angle X-ray Scattering Studies of Nanostructure in Regioregular Poly(3-hexylthiophene) and its Blends with Phenyl-C61-Butyric-Acid-Methyl-Ester

摘要

Blends of regioregular poly(3-hexylthiophene) (rr-P3HT) and fullerene derivatives, especially 1-(3-methoxycarbonyl) propyl-1- phenyl[6,6]C61 (PCBM) have been receiving recently considerable attention as materials for solution-processable photovoltaics. Bulk heterojunction solar cells with power conversion efficiency of around 5% are typically prepared from these materials by kinetic trapping through spin coating, followed by thermal annealing to promote nanoscale phase separation. One of the drawbacks of such approach is the metastable character of resulting morphologies. Herein we demonstrate that well-defined nanoscale phase separated morphologies can be achieved in rr-P3HT:PCBM system under conditions closer to equilibrium. Formation of such structures is facilitated by partitioning of PCBM into boundaries between characteristic nanofibrillar structures formed by rr-P3HT.