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A Molecular Photosensitizer in a Porous Block Copolymer Matrix-Implications for the Design of Photocatalytically Active Membranes |
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| Authors: | Avinash Chettri Jan-Hendrik Kruse Keshav Kumar Jha Lara Dröge Dr Iuliia Romanenko Dr Christof Neumann Dr Stephan Kupfer Prof?Dr Andrey Turchanin Prof?Dr Sven Rau Prof?Dr Felix H Schacher Prof?Dr Benjamin Dietzek |
| Institution: | 1. Department Functional Interfaces, Leibniz Institute of Photonic Technology (IPHT) e.V., Albert Einstein Straße 9, 07747 Jena, Germany;2. Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University Jena, Lessingstraße 8, 07743 Jena, Germany;3. Department Functional Interfaces, Leibniz Institute of Photonic Technology (IPHT) e.V., Albert Einstein Straße 9, 07747 Jena, Germany
Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany;4. Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany;5. Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany Jena Center for Soft Matter (JCSM), Philosophenweg 7, 07743 Jena, Germany;6. Institute of Inorganic Chemistry I, Ulm University, Albert Einstein Allee 11, 89081 Ulm, Germany;7. Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University Jena, Lessingstraße 8, 07743 Jena, Germany Jena Center for Soft Matter (JCSM), Philosophenweg 7, 07743 Jena, Germany |
| Abstract: | Recently, porous photocatalytically active block copolymer membranes were introduced, based on heterogenized molecular catalysts. Here, we report the integration of the photosensitizer, i. e., the light absorbing unit in an intermolecular photocatalytic system into block copolymer membranes in a covalent manner. We study the resulting structure and evaluate the orientational mobility of the photosensitizer as integral part of the photocatalytic system in such membranes. To this end we utilize transient absorption anisotropy, highlighting the temporal reorientation of the transition dipole moment probed in a femtosecond pump-probe experiment. Our findings indicate that the photosensitizer is rigidly bound to the polymer membrane and shows a large heterogeneity of absolute anisotropy values as a function of location probed within the matrix. This reflects the sample inhomogeneity arising from different protonation states of the photosensitizer and different intermolecular interactions of the photosensitizers within the block copolymer membrane scaffold. |
| Keywords: | photocatalysis porous block copolymers Ru complexes transient absorption spectroscopy transient absorption anisotropy |