Different structures and crystallinities of poly(3-hexylthiophene) films prepared from aged solutions

The influences of solvent solubility and solution aging on the crystallization of poly(3-hexylthiophene) (P3HT) films were investigated. The solubility difference rather than the evaporation rate of solvent determined the final morphology and crystallinity of film. Marginal solvents (toluene and xylene) with large solubility difference caused crystalline aggregations in solutions during the aging process and then densely stacked network-like structures in solid films. Few crystalline aggregates in good solvent chloroform resulted in a thin layer of fibrillar crystals on the substrate, while dot-like crystals deposited on the substrate from good solvent chlorobenzene since no crystalline aggregates formed in the solution.

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► The solubility difference rather than the evaporation rate of solvent determines the final morphology and crystallinity of poly(3-hexylthiophene) film.
► Marginal solvents (toluene and xylene) cause crystalline aggregations in solutions and then densely stacked network-like structures in solid films.
► Few or no crystalline aggregates form in good solvents chloroform and chlorobenzene resulting in a thin layer of fibrillar and dot-like crystals on substrate, respectively.
► Aging process increases the aggregation in solution and the crystallinity of resulting film.