Formation of nanoislands on conducting poly(3,4-ethylenedioxythiophene) films by high-energy-ion irradiation: Applications as field emitters and capacitor electrodes

Nanoislands have been fabricated on the surface of conducting poly(3,4-ethylenedioxythiophene) (PEDOT) films doped with poly(4- styrenesuifonate) (PSS) using high-energy (≈= 1-3 MeV) Cl²⁺ ion irradiation. Scanning electron microscopy and atomic force microscopy confirm the direct formation of nanoislands with diameters ranging from 50 to 300 nm and heights ranging from 40 to 120 nm. From our analysis, we propose that the formation of nanoislands might be due to micelle formation of the polymeric stabilizer poly(sodium 4-styrenesulfonate) (PSS-Na) surrounding the nuclei in the PEDOT/PSS via the high-energyion irradiation. We observe similar results for high-energy-ion irradiated polyaniline doped with PSS-Na. On using the nanoislands as nanotip emitters of a field-emission display, an increase in the current density of about five orders of magnitude is observed. Cyclic voltammetry of the PEDOT/PSS electrode with the nanoislands as the electrode shows enhanced capacitance compared with that of the PEDOT/PSS film that contains no nanostructure.