Self-assembled monolayers of novel azobenzenes for optically induced switching

Two novel azobenzenethiols containing either a sulfonamide or an amide group were synthesised and their ultrathin films were prepared by self-assembling (SA) technique. The structure of the SA monolayer (SAM) was characterised by atomic force microscopy (AFM). The switching between trans- and cis-configuration was observed by measuring the surface potential using the Kelvin probe technique while alternating irradiating the SAM with ultraviolet and visible light. A repeated switching of SAMs of 4′-(8-mercapto-octamethyleneoxy)-4-(butyl-amino-sulfonyl)azobenzene on gold with changes of the surface potential by 20 mV was observed.