Photoinduced Anisotropic Supramolecular Assembly and Enhanced Charge Transport of Poly(3-hexylthiophene) Thin Films

The self-organization of organic polymer semiconductors into ordered supramolecular assemblies commensurate with efficient charge transport is achieved by tuning a range of process parameters (e.g., film deposition method (spin vs drop cast), solvent boiling point (low vs high boiling point), polymer-dielectric interface treatment, and post-deposition processing (solvent vapor or thermal annealing)). However, these strategies present limitations for large-scale high-throughput processing due to associated pre- and/or post semiconductor deposition steps. Here, photoinduced anisotropic supramolecular assembly of P3HT chains in solution is demonstrated. UV irradiation provides for enhanced intramolecular ordering of solubilized polymer chains, and thereby effects formation of anisotropic supramolecular polymer assemblies via favorable pi-pi stacking (intermolecular interaction). Molecular ordering is thus dramatically enhanced with concomitant, enhanced charge transport characteristics of corresponding films. Additional pre- and/or post treatments are avoided.