Pedot: Pss Nanofilms Fabricated By A Nonconventional Coating Method For Uses As Transparent Conducting Electrodes In Flexible Electrochromic Devices

Nanofilms of a polymer mixer of two ionomers, poly 3,4-ethylenedioxythiophene: poly(styrene sulfonic acid) (PEDOT: PSS), were used as conductingmaterials to develop transparent conducting electrodes. It was firstly found that convective deposition, a versatile and wide-area coating method, could be used for the coating and acid treatment of PEDOT: PSS films. Electrical conductivity of the PEDOT: PSS films was significantly enhanced up to 1814 S/cm by only one-time surface treatment by a mild acid solution (4M methanesulfonic acid). This is because some PSS chains were removed out from the polymer mixer films without damage on the substrates. UV-vis-NIR spectroscopy, Raman spectroscopy, and cyclic voltammetry were used to characterize the acid-treated transparent conducting films. In this report, obtained transparent conducting PEDOT: PSS films on polyester substrates were used as flexible electrodes for fabrication of flexible electrochromic devices. Poly(3-hexylthiophene) (P3HT) was used as an active layer, which its color changed reversibly from transparent-light blue to purple with a small applied voltage (+/- 3V).