SAMOP 2023 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 4: Ultrafast Dynamics I (joint session MO/A)
MO 4.5: Vortrag
Dienstag, 7. März 2023, 12:15–12:30, F102
Systematic variation of triplet chromophore energies in iron(II) complexes linked to organic chromophores — •Moritz Lang1, Philipp Dierks2, Miguel Argüello Cordero1, Matthias Bauer2, and Stefan Lochbrunner1 — 1Institute for Physics, University of Rostock, Germany — 2Faculty of Science, CSSD, Paderborn University, Germany
For the efficient conversion of solar light, photosensitizers with appropriate absorption properties and long living excited states are crucial. Iridium and ruthenium complexes stand out due to their extraordinary stable triplett metal-to-ligand charge transfer (3MLCT) excited states but are expensive and toxic. To find sustainable alternatives, iron-based metal complexes are intensely studied. But due to an efficient internal conversion pathway mediated by metal centered states, the MLCT lifetime and therefore the performance of these types of complexes are still limited. In a systematic study the influence of various chromophores attached to homoleptic iron complexes was investigated. The excited state dynamic was studied by ultrafast transient absorption spectroscopy. For particular chromophores an additional decay component was observed, exceeding the lifetime of the otherwise predominant 3MLCT state by an order of magnitude. With fitting energy levels, a triplet state of the chromophore is populated during the relaxation process, achieving a comparably stable intermediate configuration. A better understanding and further improvement of these systems will contribute to the ultimate goal of developing efficient iron based photosensitizers for solar energy conversion.