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

• Tipo: Artigo em Revista Científica Internacional
• Data: 2005

Autores

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

Revista

Título: Journal of Physical Chemistry B

Vol. 109

Páginas: 21808-21817

ISSN: 1520-6106

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 101 Citações

Scopus - 102 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: 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.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 10