Enhanced conductivity of the Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) films using pulsed CO2 laser irradiation

Abstract

In this study, a thermal treatment method for poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) films on glass substrate was treated by a pulsed CO2 laser in the atmospheric environment. The two main parameters of the PEDOT: PSS films in thermal treatment are laser fluence and scan speed. The electrical, optical, and surface properties were measured by an in-line four-point probe instrument, spectrophotometry, atomic force microscope (AFM), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). After treatment, the conductivity was enhanced from 2.83E-02 S/cm to 59.4 S/cm in 181 s due to removing the residual water in the film. Furthermore, the transmittance value was decreased from 89.1% to 88.5%, and the surface roughness increased from 2.27 to 2.49 nm. The conductivity increased due to the reunion between PEDOT: PSS molecules and increased in the surface PEDOT/PSS ratio. However, when the laser power exceeded the durability of the PEDOT: PSS, a significant decrease in conductivity and transmittance was observed. Compared with the hotplate thermal treatment in the atmospheric environment, CO2 pulsed laser thermal treatment has advantages for PEDOT: PSS thermal treatment in a small region.