Chemistry of Materials · 2004 · 946 citations · 13 references
Natural SciencesMaterials SciencePhysicsElectronic MaterialsSemiconductor MaterialsThin FilmsConducting PolymersConductive PolymersOrganic Electronic MaterialsOrganic SemiconductorsPolymer Thin FilmsThin-film TransistorsBoilingBoiling PointCrystallization In Thin FilmsOrganic Thin-film TransistorsSolubilitySolvent Effects On Electron TransferSpin CoatingX-ray Diffraction Analysis
Chloroform is a general solvent for poly(3-hexylthiophene) (P3HT) active layers in field-effect transistors. However, its low boiling point and rapid evaporation limit the time for crystallization during the spin-coating process, and field-effect mobilities achieved for P3HT films spin-coated from chloroform are typically on the order of 0.01 cm 2 /(V s). Here we investigate a range of solvents with higher boiling points. We find that 1,2,4-trichlorobenzene with good solubility and a high boiling point significantly improves the field-effect mobilities up to 0.12 cm 2 /(V s) with on:off ratios of 10 6 . By controlling the microstructure through the choice of solvent while keeping the molecular weight fixed, we observe a clear correlation between the field-effect mobility and the degree of microcrystalline order as measured by X-ray diffraction, as well as the strength of polaronic relaxation of charge carriers in the accumulation layer as measured by optical spectroscopy of field-induced charge.
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Two-dimensional charge transport in self-organized, high-mobility conjugated polymers
Henning Sirringhaus, P. J. Brown, Richard H. Friend et al. · Nature · 1999 · 4.6K citations