Electron Hopping Dynamics in Monolayer-Protected Au Cluster Network Polymer Films by Rotated Disk Electrode Voltammetry
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- 作者：Jennifer L. Brennan ; Matthew R. Branham ; Jocelyn F. Hicks ; Andrea J. Osisek ; Robert L. Donkers ; Dimitra G. Georganopoulou ; and Royce W. Murray
- 刊名：Analytical Chemistry
- 出版年：2004
- 出版时间：October 1, 2004
- 年：2004
- 卷：76
- 期：19
- 页码：5611 - 5619
- 全文大小：162K
- 年卷期：v.76,no.19(October 1, 2004)
- ISSN：1520-6882
文摘
Electrons are transported within polymeric films of alkanethiolate monolayer-protected Au clusters (MPCs) byelectron hopping (self-exchange) between the metal cores.The surrounding monolayers, the molecular linkers thatgenerate the network polymer film, or both, presumablyserve as tunneling bridges in the electron transfers. Thispaper introduces a steady-state electrochemical methodfor measuring electron hopping rates in solvent-wettedand swollen, ionically conductive MPC films. The filmsare network polymer films of nanoparticles, coated on arotated disk electrode that is contacted by a solution of aredox species (decamethylferrocene, Cp*Fe). Controllingthe electrode potential such that the film mediates oxidation of the redox probe can force control of the overallcurrent onto the rate of electron hopping within the film,which is characterized as the apparent electron diffusioncoefficient DE. DE is translated into an apparent electronhopping rate kET by a cubic lattice model. The experimentis applied to MPC network polymer films linked by 
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-alkanedithiolates and by metal ion-carboxylate connections. We evaluate the dependencies of apparent hoppingrate on Cp*Fe concentration, film thickness, electrodepotential relative to the Cp*Fe formal potential, film-swelling solvent, and temperature. The apparent hoppingrates are in the 104-105 s-1 range, which is slower thanthose for the same kind of MPC films, but in a dry(nonswollen) state measured by electronic conductivities.
lpha.gif" BORDER=0>,-alkanedithiolates and by metal ion-carboxylate connections. We evaluate the dependencies of apparent hoppingrate on Cp*Fe concentration, film thickness, electrodepotential relative to the Cp*Fe formal potential, film-swelling solvent, and temperature. The apparent hoppingrates are in the 104-105 s-1 range, which is slower thanthose for the same kind of MPC films, but in a dry(nonswollen) state measured by electronic conductivities.