Charge transfer from an adsorbed ruthenium-based photosensitizer through an ultra-thin aluminium oxide layer and into a metallic substrate

Abstract

The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. The interaction of the dye molecule N3 (cis-bis(isothiocyanato)bis(2,2-bipyridyl-4,4 -dicarboxylato)-ruthenium(II)) with the ultra-thin oxide layer on a AlNi(110) substrate, has been studied using synchrotron radiation based photoelectron spectroscopy, resonant photoemission spectroscopy, and near edge X-ray absorption fine structure spectroscopy. Calibrated X-ray absorption and valence band spectra of the monolayer and multilayer coverages reveal that charge transfer is possible from the molecule to the AlNi(110) substrate via tunnelling through the ultra-thin oxide layer and into the conduction band edge of the substrate. This charge transfer mechanism is possible from the LUMO+2 and 3 in the excited state but not from the LUMO, therefore enabling core-hole clock analysis, which gives an upper limit of 6.0 ± 2.5 fs for the transfer time. This indicates that ultra-thin oxide layers are a viable material for use in dye-sensitized solar cells, which may lead to reduced recombination effects and improved efficiencies of future devices. © 2014 AIP Publishing LLC.

In situ XPS analysis of the atomic layer deposition of aluminium oxide on titanium dioxide

“…Our previous work has included photoemission studies of the "N3" dye * absorbed on an ultra-thin aluminium oxide layer (grown on a nickle aluminium single crystal) 8 . However, growing such a film on titanium dioixde is a more challenging problem where getting repeatable ultra-thin films (a few monolayers) without contaminants at the interface is required.…”

Resonant X-ray photo-oxidation of light-harvesting iron (II/III) N-heterocyclic carbene complexes

“…The electronic structure properties of transition metal complexes can be studied using X-ray spectroscopy methods including X-ray absorption spectroscopy (XAS) 22 , 23 and photoelectron spectroscopy (PES) 24 – 26 . XAS and emerging time-resolved X-ray techniques 27 have contributed to a better understanding of the properties of iron–carbene photosensitisers in terms of electronic structure 28 – 31 , excited-state deactivation pathways 32 , and excited-state dynamics such as hot branching 33 and wave packet oscillations 34 .…”

Resonant inelastic X-ray scattering of a Ru photosensitizer: Insights from individual ligands to the electronic structure of the complete molecule

“…2 This study is focused on the "N3" dye, cis-bis(isothiocyanato) bis(2,2 ′ -bipyridyl-4,4 ′ -dicarboxylic acid) ruthenium(II) also known as Ru535, which has become a benchmark molecule for use in DSSCs and has been previously studied using photoelectron spectroscopies on rutile titanium dioxide, 3 gold, 4,5 and aluminum oxide surfaces. 6 N3 bonds to oxide surfaces primarily through the carboxyl groups of the bi-isonicotinic acid (2,2 ′ -bipyridyl-4,4 ′ -dicarboxylic acid) ligands, which in turn is made up of two isonicotinic acid molecules (pyridine-4-carboxylic acid). These molecules, shown in Fig.…”