Electrochemical characterization of polyelectrolyte/gold nanoparticle multilayers self-assembled on gold electrodes

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Chirea, M (Author) FCUP; Garcia Morales, V (Author) Other; Manzanares, JA (Author) Other; Pereira, C (Author) FCUP; Gulaboski, R (Author) Other; Silva, F (Author) FCUP

Journal

Title: Journal of Physical Chemistry B

Vol. 109

Pages: 21808-21817

ISSN: 1520-6106

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 101 Citations

Scopus - 102 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-0EF

DOI: 10.1021/jp0537815

Abstract (EN): Polyelectrolyte/gold nanoparticle multilayers composed Of poly(L-lysine) (pLys) and mercaptosuccinic acid (MSA) stabilized gold nanoparticles (Au NPs) were built up using the electrostatic layer-by-layer self-assembly technique upon a gold electrode modified with a first layer of MSA. The assemblies were characterized using UV-vis absorption spectroscopy, cyclic and square-wave voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy. Charge transport through the multilayer was studied experimentally as well as theoretically by using two different redox pairs [Fe(CN)(6)](3-/4-) and [Ru(NH3)(6)](3+/2+). This paper reports a large sensitivity to the charge of the outermost layer for the permeability of these assemblies to the probe ions. With the former redox pair, dramatic changes in the impedance response were obtained for thin multilayers each time a new layer was deposited. In the latter case, the multilayer behaves as a conductor exhibiting a strikingly lower impedance response, the electric current being enhanced as more layers are added for Au NP terminated multilayers. These results are interpreted quite satisfactorily by means of a capillary membrane model that encompasses the wide variety of behaviors observed. It is concluded that nonlinear slow diffusion through defects (pinholes) in the multilayer is the governing mechanism for the [Fe(CN)(6)](3-/4-) species, whereas electron transfer through the Au NPs is the dominant mechanism in the case of the [Ru(NH3)(6)](3+/2+) pair.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10