Suppression of electron-transfer characteristics of ferrocene by OTS monolayer on a silicon/electrolyte interface.
J Colloid Interface Sci
; 299(2): 777-84, 2006 Jul 15.
Article
en En
| MEDLINE
| ID: mdl-16600277
The passivating behavior of self-assembled monolayers (SAMs) of octadecyltrichlorosilane (OTS) on an n-type Si(100) electrode with and without a redox species like ferrocene in a polar non-aqueous medium has been investigated using techniques like contact angle measurements, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to understand the role of the monolayer. The electron-transfer behavior of ferrocene is found to be drastically affected by the presence of monolayer and the reasons for these are analyzed as a function of the change in resistance, dielectric thickness and coverage of the monolayer. Electrochemical impedance analysis in the presence of ferrocene gives the monolayer coverage as 0.998 and the apparent rate constant calculated from this gives 4.85 x 10(-12) cm s(-1) in comparison with 4.4 x 10(-8) cm s(-1) for a similar electrode without any monolayer. A positive shift of 200 mV in the flat-band potential after monolayer formation also suggests the covalent coupling of the silane monolayer offering a protective barrier.
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01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Colloid Interface Sci
Año:
2006
Tipo del documento:
Article
País de afiliación:
India
Pais de publicación:
Estados Unidos