Hannover 2013 – scientific programme
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MO: Fachverband Molekülphysik
MO 28: Photochemistry
MO 28.4: Talk
Friday, March 22, 2013, 12:00–12:15, F 102
Luminescence Quenching of non-Noble Metal-Photosensitizers in a Photocatalytic Model System — •Aleksej Friedrich1, Patrick Schwarzbach1, Stefanie Tschierlei1, Esteban Mejia2, Henrik Junge2, Matthias Beller2, and Stefan Lochbrunner1 — 1Institute of Physics, University of Rostock, Germany — 2Leibniz-Institut für Katalyse Rostock, Germany
The efficient hydrogen generation by photocatalytic water splitting is a challenge in the field of renewable energy. In the last years several homogeneous systems have been investigated. Disadvantage of most of them is the application of rare metals like ruthenium or iridium. In this contribution, we study an active, photocatalytic model system consisting of a non-noble metal-photosensitizer (PS), an iron-catalyst, and triethylamine (TEA) as a sacrificial reductant [1]. Here, we focus on the energy and electron transfer reaction steps of the PS after optical excitation and compare the behavior of different copper sensitizers.
Luminescence quenching by TEA and the catalyst is studied by steady-state and time-resolved luminescence measurements. The measured luminescence lifetimes of the PSs vary between 70 ns and 50 µs. We see a correlation between the turn over number and the lifetime indicating that good PSs exhibit a minimum lifetime of about 3 µs. Quenching by the iron-catalyst is found to be efficient reducing the PS lifetime to the range of 80 ns to 500 ns. Contrary, quenching of the sacrificial reductant TEA is inefficient indicating that the oxidative pathway dominates.
[1] S.-P. Luo et al., Angew. Chem. 2012, accepted.