Toggle Main Menu Toggle Search

Open Access padlockePrints

Lateral charge transfer in DNA monolayers

Lookup NU author(s): Professor Andrew HoultonORCiD, Dr Ben Horrocks

Downloads

Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Abstract

The charge transport in films consisting of metal complexes bound to DNA monolayers on Si(111) substrates was probed using scanning electrochemical microscopy (SECM) in the steady-state feedback mode. Lateral charge transport on the substrate - the source of SECM feedback - was found to depend on the charge exchange rate between the surface and solution as well as the rate of diffusion of charged, surface-bound species. A semi-analytical description of the steady-state SECM experiment with lateral charge transport was developed and used to analyze steady-state approach curves in solutions of various metal complex mediators at Si(111)/DNA substrates. Several possible charge transfer mechanisms (e.g., physical surface diffusion, electron hopping between DNA-bound redox species and DNA-mediated long range electron transfer) were explored as possible explanations for high positive feedback observed in Ru(bipy) 32+ and Ru(NH3)63+ solutions. While Ru(bipy)33+ was found to inject charge into the silicon valence band across the organic monolayer, surprisingly fast charge diffusion in Ru(NH3)63+/dsDNA films (effective diffusion coefficient, 2.1 × 10-5 cm2 s-1) was attributed to physical diffusion of the ruthenium centers on the surface. Anionic metal complexes are excluded from the DNA film (FeCN 64-, IrCl63-) and show negative feedback in the SECM experiment. Co(bipy)33+ also shows negative feedback which is presumably due to a much lower electron transfer self-exchange rate compared to the Ru(NH3)63+/2+couple. © 2004 The Electrochemical Society, Inc.


Publication metadata

Author(s): Mirkin MV, Lie LH, Houlton A, Horrocks BR

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: 205th Meeting of The Electrochemical Society

Year of Conference: 2004

Pages: 886

ISSN: 1091-8213

Publisher: Electrochemical Society, Inc.


Share