The University of Southampton
University of Southampton Institutional Repository

Tuning electrochemical rectification via quantum dot assemblies

Tuning electrochemical rectification via quantum dot assemblies
Tuning electrochemical rectification via quantum dot assemblies
A novel approach to tuning electrochemical rectification using 2D assemblies of quantum dots (QDs) is presented. Asymmetric enhancement of the oxidation and reduction currents in the presence of the Fe(CN)63-/4- redox couple is observed upon adsorption of QDs at thiol-modified Au electrodes. The extent of the electrochemical rectification is dependent on the average QD size. A molecular blocking layer is generated by self-assembling 11-mercaptoundecanoic acid (MUA) and an ultrathin film of poly(diallyldimethylammonium chloride) (PDADMAC) on the electrode. The polycationic film allows the electrostatic adsorption of 3-mercaptopropionic acid (MPA)-stabilized CdTe QDs, generating 2D assemblies with approximately 0.4% coverage. The QD adsorption activates a fast charge transfer across the blocking layer in which the reduction process is more strongly enhanced than the oxidation reaction. The partial electrochemical rectification is rationalized in terms of the relative position of the valence (VB) and conduction band (CB) edges with respect to the redox Fermi energy (?redox). Quantitative analysis of the exchange current density obtained from electrochemical impedance spectroscopy demonstrates that the enhancement of charge transport across the molecular barrier is strongly dependent on the position of the QD valence band edge relative to ?redox. The average electron tunneling rate constant through the QD assemblies is estimated on the basis of the Gerischer model for electron transfer. ? 2010 American Chemical Society.
0002-7863
Kissling, G.P.
b9ad7a6b-70b9-48b6-ac03-a189278dd2d9
B?nzli, C.
91e0266e-dd7b-4957-8c26-e520d8be8d40
Ferm?n, D.J.
3bfcec3e-75fc-487b-9367-ea8c805f4c0d
Kissling, G.P.
b9ad7a6b-70b9-48b6-ac03-a189278dd2d9
B?nzli, C.
91e0266e-dd7b-4957-8c26-e520d8be8d40
Ferm?n, D.J.
3bfcec3e-75fc-487b-9367-ea8c805f4c0d

Kissling, G.P., B?nzli, C. and Ferm?n, D.J. (2010) Tuning electrochemical rectification via quantum dot assemblies. Journal of the American Chemical Society, 132 (47). (doi:10.1021/ja106149g).

Record type: Article

Abstract

A novel approach to tuning electrochemical rectification using 2D assemblies of quantum dots (QDs) is presented. Asymmetric enhancement of the oxidation and reduction currents in the presence of the Fe(CN)63-/4- redox couple is observed upon adsorption of QDs at thiol-modified Au electrodes. The extent of the electrochemical rectification is dependent on the average QD size. A molecular blocking layer is generated by self-assembling 11-mercaptoundecanoic acid (MUA) and an ultrathin film of poly(diallyldimethylammonium chloride) (PDADMAC) on the electrode. The polycationic film allows the electrostatic adsorption of 3-mercaptopropionic acid (MPA)-stabilized CdTe QDs, generating 2D assemblies with approximately 0.4% coverage. The QD adsorption activates a fast charge transfer across the blocking layer in which the reduction process is more strongly enhanced than the oxidation reaction. The partial electrochemical rectification is rationalized in terms of the relative position of the valence (VB) and conduction band (CB) edges with respect to the redox Fermi energy (?redox). Quantitative analysis of the exchange current density obtained from electrochemical impedance spectroscopy demonstrates that the enhancement of charge transport across the molecular barrier is strongly dependent on the position of the QD valence band edge relative to ?redox. The average electron tunneling rate constant through the QD assemblies is estimated on the basis of the Gerischer model for electron transfer. ? 2010 American Chemical Society.

Full text not available from this repository.

More information

Published date: 4 November 2010

Identifiers

Local EPrints ID: 422004
URI: https://eprints.soton.ac.uk/id/eprint/422004
ISSN: 0002-7863
PURE UUID: d9a7b81d-730e-4272-bb81-b32ecf1dd7bb
ORCID for G.P. Kissling: ORCID iD orcid.org/0000-0003-4701-7160

Catalogue record

Date deposited: 12 Jul 2018 16:31
Last modified: 26 Nov 2019 02:13

Export record

Altmetrics

Contributors

Author: G.P. Kissling ORCID iD
Author: C. B?nzli
Author: D.J. Ferm?n

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×