Electroless deposition of silver on poly(3, 4-ethylenedioxythiophene): role of the organic ions used in the course of electrochemical synthesis

The electroless deposition of silver is studied on poly(3, 4-ethylenedioxythiophene) (PEDOT) layers synthesized in the presence of excess of perchlorate ions with and without the addition of two organic dopants: dodecylsulfate (DDS) or polystyrenesulfonate (PSS). Silver deposition is carried out at the expense of oxidation of the pre-reduced PEDOT layers using either Ag⁺ cation or AgEDTA]^3? complex anion solutions. The amount of deposited silver is monitored by voltammetric stripping. The type of the metal deposit is imaged by SEM. It is found that there are marked differences between the three types of PEDOT with respect to the amount of deposited silver and size distribution of the metallic species. In both silver plating solutions, the largest amount of silver is deposited on PEDOT/DDS, followed by PEDOT/PSS and PEDOT/ClO₄ ^?. These results are discussed in the context of possible structural difference of the three types of PEDOT layers. The comparison between the silver deposits obtained in the two silver plating solutions shows finer dispersion and larger amount of the metallic phase obtained in the presence of the silver complex anions. This solution presents a better opportunity to obtain homogeneous distribution of silver crystalline species on the PEDOT surface.