Direct Imaging of the Electrochemical Deposition of Poly(3,4-ethylenedioxythiophene) by Transmission Electron Microscopy

Jinglin Liu, Bin Wei, Jennifer D. Sloppy, Liangqi Ouyang, Chaoying Ni, and David C. Martin, 2015
electrochemical deposition of poly(3,4-ethylenedioxythiophene)
Image courtesy of ACS Macro lett

Abstract

Conjugated polymers are electronically and ionically active organic materials of interest for use in a variety of devices. Electrochemical deposition is a convenient method for precisely fabricating conjugated polymer thin films, yet a detailed, quantitative understanding of nucleation and growth mechanisms has remained elusive. Here, we report direct imaging of the in situ electrochemical deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) from an aqueous solution of EDOT monomer using Transmission Electron Microscopy with an electrochemical liquid flow cell. We found that PEDOT deposition began preferentially at the edge of the glassy carbon anodes at the beginning of the reaction. Fluctuating clusters of liquid-like oligomers were observed to form near the electrode surfaces. As the reaction continued, both the nucleation of new domains as well as the growth of pre-existing PEDOT deposits were observed, leading to systematic increases in film thickness and roughness.

Impact Statement

Conjugated polymers are electronically and ionically active organic materials of interest for use in a variety of devices. This paper demonstrates the electrochemical deposition of a PEDOT (poly(3,4-ethylenedioxythiophene) ) film onto a glassy carbon working electrode using the Poseidon in situ LC-(S)TEM system.