University of Surrey

Test tubes in the lab Research in the ATI Dance Research

Dipole Moment Reversal in a Polar Organic Monolayer Probed by Sum and Difference Frequency Spectroscopy

García Rey, N, Sacchi, Marco, Jenkins, SJ and Arnolds, H (2017) Dipole Moment Reversal in a Polar Organic Monolayer Probed by Sum and Difference Frequency Spectroscopy The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces, 121 (12). pp. 6692-6700.

[img] Text
jp_2016_12700n_revised.pdf - Accepted version Manuscript
Restricted to Repository staff only until 7 March 2018.
Available under License : See the attached licence file.

Download (1MB)
[img] Text
jp_2016_12700n_SupportingInformation.pdf
Restricted to Repository staff only until 7 March 2018.

Download (980kB)
[img]
Preview
Text (licence)
SRI_deposit_agreement.pdf
Available under License : See the attached licence file.

Download (33kB) | Preview

Abstract

We investigate the adsorption of pyridine on Cu(110) in ultra-high vacuum with a combination of work function measurements and femtosecond infrared-visible sum and difference frequency generation (SFG/DFG). A monolayer of pyridine substantially reduces the work function by 2.9 eV due to the large pyridine dipole. We perform density functional theory (DFT) calculations that provide us with a dipole moment change upon adsorption in very good agreement with the experimental results. The pyridine dipole strongly enhances the sum frequency response of the surface electrons, but surprisingly reduces the surface difference frequency signal. We propose a model based on the static electric field-induced nonlinear optical response generated by the collective electric field of the adsorbate layer. The pyridine dipole switches direction from the ground to the excited electronic state, as charge moves from nitrogen to the ring. SFG can then be enhanced by the electric field of adsorbed pyridine in its ground electronic state, while the 2.33 eV incident photon in DFG excites electrons into the pyridine LUMO, which reverses the electric field in the adsorbate layer and reduces the nonlinear optical response. The model is verified by 2.33 eV pump – SFG probe spectroscopy, where the pump pulse is found to reduce the surface electron response on a subpicosecond timescale. This demonstrates the potential to manipulate the work function in organic electronic devices by photon-induced dipole moment reversal.

Item Type: Article
Subjects : Chemistry
Divisions : Faculty of Engineering and Physical Sciences > Chemistry
Authors :
NameEmailORCID
García Rey, NUNSPECIFIEDUNSPECIFIED
Sacchi, Marcom.sacchi@surrey.ac.ukUNSPECIFIED
Jenkins, SJUNSPECIFIEDUNSPECIFIED
Arnolds, HUNSPECIFIEDUNSPECIFIED
Date : 7 March 2017
Identification Number : https://doi.org/10.1021/acs.jpcc.6b12700
Copyright Disclaimer : Copyright © 2017 American Chemical Society
Related URLs :
Depositing User : Symplectic Elements
Date Deposited : 10 Mar 2017 14:47
Last Modified : 20 Jun 2017 15:19
URI: http://epubs.surrey.ac.uk/id/eprint/813743

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year


Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800