Selective deposition of gold nanoparticles on the top or inside a thin conducting polymer film, by combination of electroless deposition and electrochemical reduction

Abstract

In this paper we present the procedures allowing for synthesis of the composite systems in which Au nanoparticles are located: (i) only on the surface of the polymer film, (ii) only inside the polymer matrix or (iii) both on the polymer surface and in the polymer film. Thin poly(1,8-diaminocarbazole) (PDACz) films were electrodeposited on gold or highly oriented pyrolytic graphite (HOPG) electrodes from acetonitrile solution. Then, Au nanoparticles (NPs) were formed either by electroless deposition on the polymer layer in the solution of HAuCl4 or by electrochemical reduction of AuCl4− incorporated into the polymer matrix, carried out in the solution of HClO4. The amount of deposited Au was determined from electrochemical quartz crystal microbalance measurements and from the reduction charge. The role of protonation of amino groups of the polymer in the process of AuCl4− insertion into the polymer matrix has been discussed. A distribution of Au nanoparticles on the top and inside the polymer film was studied by SEM and TEM images of the polymer cross sections prepared by focused ion beam (FIB) method.