Field-effect transistor with the water-soluble self-acid-doped polyaniline thin films as semiconductor

UV-Vis spectroscopy and conductivity of the water-soluble self-acid-doped conducting polyanilines, poly(aniline-co-N-propanesulfonic acid aniline) (PAPSAH) and sulfonic acid ring substituted polyaniline (SPAN), in comparison with those of HCl-doped polyaniline, show that the decreases in polaron delocalization and structural order result from the steric hindrance imparted by the sulfonic acid substituent. The field-effect transistors (FETs) are fabricated with the water-soluble self-acid-doped conducting polyanilines, PAPSAH and SPAN films, respectively, as the semiconducting layer. These FETs have ideal source current-drain source voltage characteristics and their field-effect mobilities can reach 2.14 (PAPSAH) and 0.33 cm2 V−1 s−1 (SPAN), which are close to those of the amorphous silicon inorganic transistors (0.1–1.0 cm2 V−1 s−1) used extensively at present. These FETs are found to be environmentally more stable than those of other polyaniline FETs.