Supramolecular Self-Assembly and Photo-Induced Transition of a Halogenated Azo-Benzene Molecule on Au(111) Surface

Azobenzene derivatives are a unique class of photo-switch molecules with promising potential for nanoscale optical applications. We have studied the self-assembly and photo-induced mechanical switching azobenzene on Au(111) at single-molecule level by using scanning tunneling microscope (STM). 4,4′-Dibromo-azobenzene (Br-AB) assembled into two types well-ordered structures surfaces in trans-isomer configuration. Br-AB experienced configurational changes from trans-to-cis photo-isomerization upon exposure to UV light. This was observed occur random sites ordered structure, evidenced appearance bright protrusions height increment. Our results may open up new routes engineer molecular devices.