Fabrication of a touch sensor for flat panel displays using poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) with dimethylsulfoxide by soft lithography

In this study, a transparent conductive-polymer-based sensor array designed for use in a touch screen panel was fabricated using soft lithography. One of the most promising conductive polymers, poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS), was used as the conductive material, and the secondary dopant dimethyl sulfoxide (DMSO) was used to increase the conductivity. The experiments were conducted using various DMSO concentrations in PEDOT:PSS in order to identify the optimum conditions to achieve high conductivity and transmittance. The electrical properties of PEDOT:PSS thin films were investigated using a four-point probe, and their transmittance was determined using an UV-vis spectrometer. The surface morphology was observed by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). A stable conductivity in the range of 110-204 S/cm was obtained at 0-30% DMSO concentrations, and the transmittances were greater than 92% in the visible range.