Issue 34, 2009

Controlling the non-resonant chemical mechanism of SERS using a molecular photoswitch

Abstract

In this work we present a detailed investigation of the Raman properties of a dithienylethene photoswitch interacting with a small gold cluster (Au19+) using time-dependent density functional theory (TD-DFT). The enhancement mechanism (CHEM) due to the molecule–surface chemical coupling in surface-enhanced Raman scattering (SERS) has been characterized for this system. We demonstrate that it is possible to control the CHEM enhancement by switching the photoswitch from its closed form to its open form. The open form of the photoswitch is found to be the strongest Raman scatterer when adsorbed on the surface whereas the opposite is found for the free molecule. This trend is explained using a simple two-state approximation. In this model the CHEM enhancement scales roughly as (ωX/[small omega, Greek, macron]e)4, where ωX is the HOMO–LUMO gap of the free molecule and [small omega, Greek, macron]e is an average excitation between the HOMO of the photoswitch and the LUMO of the metal. We propose that the ability of this photoswitch to switch reversibly from open to closed will make it an excellent probe to control the CHEM enhancement of SERS.

Graphical abstract: Controlling the non-resonant chemical mechanism of SERS using a molecular photoswitch

Article information

Article type
Paper
Submitted
09 Mar 2009
Accepted
22 Apr 2009
First published
22 May 2009

Phys. Chem. Chem. Phys., 2009,11, 7424-7429

Controlling the non-resonant chemical mechanism of SERS using a molecular photoswitch

S. M. Morton, E. Ewusi-Annan and L. Jensen, Phys. Chem. Chem. Phys., 2009, 11, 7424 DOI: 10.1039/B904745J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements