Fabrication and Characterization of Aluminum Solid Capacitors Using Aqueous Dispersion of Conductive Polymers

Abstract

The poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonic acid) (PEDOT/PSS), in the form of aqueous dispersion of colloidal gel particles, had advantages as a cathode of aluminum solid capacitors due to facile fabrication and high material efficiency and cost performance. In this study, different grades of PEDOT/PSS with various conductivities and particles sizes were used to fabricate the capacitors, and equivalent series resistance (ESR) and capacitance (Cap) were evaluated. It was found that electrical conductivity of the PEDOT/PSS significantly increased by adding ethylene glycol and dimethyl sulfoxide, which reduced the ESR of capacitors at 1 MHz regardless of the particle size. On the other hand, the use of PEDOT/PSS with smaller particle size to fill in the pores of the etched aluminum electrode resulted in a decrease in ESR and increase of Cap at 120 Hz.