Drain Current in Poly(3‐hexylthiophene) Solutions during Film Formation: Correlations to Structural Changes

Abstract Concurrent in situ Raman spectroscopic studies and drain current measurements were performed during drop‐cast poly(3‐hexylthiophene) (P3HT) film formation. Together, these techniques allow interrogation and elucidation of the evolution of P3HT structural changes and associated electrical characteristics as the solvent evaporates. Two observations are especially significant: i) solvent continued to be present in the developing thin‐film at the point where the drain current exhibited a sharp increase and ii) continued to be observed after crystallization of the polymer. The in situ studies provide vital insights into the polymer organization and chain alignment processes at the molecular and macroscopic scales. The results suggest that final conjugated polymer thin‐film morphology can be tailored for enhanced performance and desired electronic properties through quenching of the active polymer layer at a specified time during the solidification process.