Berlin 2024 – scientific programme
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DS: Fachverband Dünne Schichten
DS 10: Thin Film Application
DS 10.6: Talk
Wednesday, March 20, 2024, 16:15–16:30, A 060
Reversible Photoalignment of Azobenzene inside the pores of thin MOF films — •Tillmann Koehler1,2, Alexander Mundstock3, Jürgen Caro3, and Frank Marlow1,2,4 — 1Max-Planck-Institut für Kohlenforschung — 2Universität Duisburg-Essen — 3Leibniz Universität Hannover — 4Center for Nanointegration Duisburg-Essen
Integrating molecular switches within the cavities of metal-organic frameworks (MOFs) represents a promising avenue for achieving all-optical switching - a crucial approach to address the escalating energy demands of contemporary internet and communication technologies. Our primary focus centers on employing azobenzene and its derivatives as guest molecules within these frameworks. Azobenzene can undergo photochemical switching between the stable trans-isomer and the metastable cis-isomer. As hosts, we utilize thin films of MOFs, a hybrid material class composed of metal centers interconnected by organic linkers. They are synthesized via liquid phase epitaxy by alternating exposition to metal and linker. The state of the isomers and their orientation inside the pores can be analyzed using linearly polarized UV/Vis spectroscopy. Our findings reveal that azobenzene encapsulated within the pores of MOF type HKUST-1 not only undergoes efficient isomerization, leading to reversible changes in optical properties, but also exhibits the uncommon phenomenon of photoalignment [1]. Results for higher loadings and more perfect films are shown. [1] J. Phys. Chem. Lett. 2021, 12, 36, 8903*8908
Keywords: Metal-Organic Framework (MOF); Azobenzene/Azobenzol; Photoalignment; Photochemistry; SURMOF