Reversible switching of tetra-tert-butyl-azobenzene on a Au(111) surface induced by light and thermal activation

• DOI: 10.1016/j.cplett.2007.07.005
• Publication Date: 2007-07-08T07:13:35Z
• Authors: Sebastian Hagen; Felix Leyssner; Dhananjay Nandi; Martin Wolf; Petra Tegeder
• Keywords: Azobenzene; Tetra

Abstract Two-photon photoemission spectroscopy is employed to analyze reversible changes in the electronic structure of the molecular switch tetra- tert -butyl-azobenzene (TBA) adsorbed on Au(1 1 1), which are induced by UV-light and thermal activation. Cycles of illumination and annealing steps confirm the reversibility of the switching process, which we assign to a trans / cis -isomerization of TBA molecules in direct contact with the Au(1 1 1) surface. Pronounced changes in the photoelectron spectra due to UV-light exposure allow to calculate an effective cross section of σ eff ≈ 8 × 10 −22 cm −2 at 4.14 eV and σ eff ≈ 4 × 10 −21 cm −2 at 4.4 eV, respectively, for the trans - to cis -isomerization.