A solvent mixing method has been developed to enhance the field-effect mobility of poly(3-hexylthiophene)(P3HT)

in which a poor-solvent

i.e.dioxane

was added into P3HT chloroform solutions.UV-Vis absorption spectra

grazing-incidence X-ray diffraction and atom force microscope reveal that the P3HT films obtained from pure chloroform solution have poor crystallinity and the molecules in crystal domains adopt a"plane-on"mode.However

the films obtained from mixing solvent show significant increase in crystallinity and change of molecule orientation to an"edge-on"mode.The reason for these improvements can be ascribed to the formation of ordered P3HT aggregates upon the addition of poor solvent

which can promote the crystallization of P3HT molecules and neutralize the adverse impact caused by the fast evaporation of low boiling point solvent.Therefore

when the concentration of dioxane is 10 vol%

the filed-effect mobility reaches the highest value 1.7 × 10-2 cm2V-1 s-1

while the mobility of the P3HT films obtained from pure chloroform is 3.1 × 10-4 cm2 V-1 s-1.The filed-effect mobility increased by a factor of 50.This method is a simple procedure for the fabrication of ordered aggregated P3HT films and can be applied to a wide range of commercial applications without post-treatment.