Highly conductive PEDOT:PSS film by doping p-toluenesulfonic acid and post-treatment with dimethyl sulfoxide for ITO-free polymer dispersed liquid crystal device

Abstract

In this paper, the highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film realized by applying the doping technique and the post-treatment process is demonstrated. The conductivity of the spin coated PEDOT:PSS film enhanced greatly from 0.7 S/cm to 736 S/cm after 1.25% of p-toluenesulfonic acid solution (50 wt%) was doped into the PEDOT:PSS aqueous dispersion. The post-treatment using dimethyl sulfoxide further improved the conductivity to 1549 S/cm. The highly conductive PEDOT:PSS film was used as transparent electrode to fabricate ITO-free polymer dispersed liquid crystal (PDLC) cell. The experimental results showed that the electro-optical properties of the PDLC cell fabricated by the highly conductive PEDOT:PSS film were comparable to those of the PDLC cell constructed by ITO. This study reveals that the highly conductive PEDOT:PSS film is a prospective material for manufacturing ITO-free liquid crystal devices.

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