Regensburg 2025 – scientific programme
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DS: Fachverband Dünne Schichten
DS 15: Organic Thin Films, Organic-Inorganic Interfaces
DS 15.7: Talk
Friday, March 21, 2025, 11:30–11:45, H3
Spatially resolved work-function manipulation of azobenzene-functionalized self-assembled monolayers by optical stimulation — Jan Böhnke1, Beatrice Andres1, Larissa Boie1,2, Angela Richter1, Cornelius Gahl1, Martin Weinelt1, and •Wibke Bronsch1,3 — 1Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany — 2Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland — 3Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14-km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, Italy
Strongly differing static dipole moments of the trans and cis isomers of photochromic azobenzene allow for optical work-function switching of azobenzene-functionalized self-assembled monolayers (SAMs) [1,2]. We apply these properties in a fundamental experiment to manipulate the area size of the switched SAM [3]. In our experiments we spatially resolve the transient isomerization profile of the SAM after UV illumination by means of photoemission electron microscopy imaging. We demonstrate the capability of spatial tuning of the SAM's work function and discuss the role of the laser spot profile in generating sharp edges or gradual changes of the work function across the sample.
[1] Bronsch et al., Appl. Phys. Lett. 111, 081601 (2017).
[2] Bronsch et al., J. Phys.: Condens. Matter 29, 484002 (2017).
[3] Böhnke et al., Appl. Phys. Lett. 124, 191601 (2024).
Keywords: optical switches; PEEM; Self-assembled monolayers; work function; azobenzene