Transient absorption spectroscopy on spiropyran monolayers using nanosecond pump–probe Brewster angle reflectometry

Siebenhofer, Bernhard and Gorelik, Sergey and Lear, Martin J. and Song, Hong Yan and Nowak, Christoph and Hobley, Jonathan (2013) Transient absorption spectroscopy on spiropyran monolayers using nanosecond pump–probe Brewster angle reflectometry. Photochemical & Photobiological Sciences, 12 (5). pp. 848-853. ISSN 1474-905X

Full content URL: http://dx.doi.org/10.1039/c3pp25397j

Documents
PCP-2013.pdf
[img]
[Download]
[img]
Preview
PDF
PCP-2013.pdf - Whole Document

740kB
Item Type:Article
Item Status:Live Archive

Abstract

Self-assembled monolayers of 11-(3’,3’-dimethyl-6,8-dinitrospiro[chromene-2,2’-indoline]-1’-yl) undecanoic acid (amphiphilic spiropyran) at the air–water interface are studied using Brewster angle reflectometry. Transient kinetics of the spiropyran to merocyanine conversion are recorded in a UV-pump, VIS-probe configuration. By varying the probe wavelength using an optical parametric oscillator, we are able to reconstruct absorption spectra of intermediate states with a time-resolution of 10 nanoseconds, limited by the temporal convolution of the two laser pulses. After UV irradiation, spiropyran converts to merocyanine in two stages. The first occurs within a timescale of several tens of nanoseconds and is heavily convoluted with the system response time, whereas the second stage occurs over a few hundred nanoseconds. During the rise time there is a small red shift in the transient absorption spectrum of ∼20 nm. We assign the red shift and the slower kinetics to the isomerization of a merocyanine isomer cis about the central methine bond to those that are trans about the same bond.

Keywords:Brewster angle reflectometry, Spiropyran, Merocyanine, Self-assembled monolayers
Subjects:F Physical Sciences > F200 Materials Science
F Physical Sciences > F170 Physical Chemistry
F Physical Sciences > F160 Organic Chemistry
Divisions:College of Science > School of Chemistry
ID Code:17132
Deposited On:23 Apr 2015 11:21

Repository Staff Only: item control page