Self-Assembly of Well-Defined Poly(3-hexylthiophene) Nanostructures toward the Structure-Property Relationship Determination of Polymer Solar Cells

The control of the nanoscale morphology of the active layer is vital to obtaining high-performance polymer solar cells (PSCs). In this study, the effects of the nanowire length on the nanoscale organization of the active layer as well on the final performance of PSCs based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) are presented. P3HT nanowires with different lengths were obtained by sonication-assisted self-assembly. The nanowire length increased as the temperature increased during sonication. PSCs based on P3HT nanowires/ PCBM blends with different nanowire lengths were fabricated, and their performance was systemically investigated. When the P3HT nanowire length increased, the short-circuit current (J(sc)) and fill factor (FF) of the devices were both enhanced, which resulted in a higher performance. Morphological characterization of the active layer showed that the longer P3HT nanowires in the active layer have a higher tendency to form interpenetrating network structures that facilitate the charge transport in the active layer.