Styrenic polymers as gate dielectrics for pentacene field-effect transistors

The effect of the chemical structure of the dielectric layer in organic thin-film transistors was examined by evaporating pentacene onto five different styrenic polymer dielectrics: poly(styrene), poly(4-hydroxystyrene), poly(4-methylstyrene), poly(4-vinylpyridine), and poly(2-vinylnaphthalene). We find that the polymer has a significant effect, with measured field-effect mobilities ranging from between 0.1 and $1{\mathrm{cm}}^2∕\mathrm{V}\mathrm{s}$ . This variation appears uncorrelated with either the polymer suface morphology or the observed pentacene crystallite size. The distribution of mobility, threshold voltage, on/off ratio, and subthreshold swing observed for each of the polymer dielectrics is presented.