ÖPG-CMD Joint Meeting 2026

P044 - Photoisomerization of azobenzene derivatives on Au (111) using various photon energies and polarizations

Sep 23, 2026, 1:30 PM

1h

RESOWI B+F (University of Graz)

1) Poster M18 - Light-driven Processes at Interfaces Poster session

Speakers

Mr Haraprasad Mandal (University of Graz)Mr Paul Schöngrundner (University of Graz)

Description

Azobenzene derivatives continue to serve as model systems for studying photoisomerization on surfaces. Among them, tetra-tert-butyl azobenzene (TBA) is particularly suitable, due to its chemical stability, large steric groups, and well-defined trans and cis configurations that can easily be identified in scanning tunnelling microscopy (STM) images.1,2,3 Using a tunable femtosecond laser and ultrahigh vacuum STM at low temperatures, we systematically investigated the photon-energy- and polarization-dependent trans-to-cis isomerization of TBA on Au(111). STM imaging was used to determine the configuration of individual molecules before and after laser exposure. The switching efficiency was studied for wavelengths between 350 nm and 800 nm and for different (s/p) polarization directions of the incident light. Our results provide insight into the parameters that steer TBA photoisomerization on Au(111) and demonstrate the capability of our laser–STM platform for controlled photochemical studies of single molecules.