In situ scanning tunneling microscopy imaging of electropolymerized poly(3,4-ethylenedioxythiophene) on an iodine-modified Au(111) single crystal electrode

摘要

The electrochemical polymerization of 3,4-ethylenedioxythiophene (EDOT) on an iodine-modified Au(111) single crystal electrode in aqueous 0.10 M HClO_4 was investigated by cyclic voltammetry (CV) and electrochemical scanning tunneling microscopy (EC-STM). The cyclic voltammetric and EC-STM data revealed the stability of the iodine adlayer provided a suitable potential range for EDOT electropolymerization was controlled at 1.20 V (vs. the reversible hydrogen electrode). EC-STM was used to examine the formation of the PEDOT adlayer on the iodine-modified Au(111) electrode. In situ electropolymerization of EDOT was carried out by slowly increasing the electrode potential to 1.20V. This process resulted in the formation of single molecular chains of PEDOT with a diameter of 0.90nm and lengths of 5-7 nm. Higher resolution STM images further revealed PEDOT nanostructures with bent polymer backbones at angles of 105°, 144° and 180°. The growth of PEDOT multi-layers was observed when the potential was held for a longer time.