Azobenzene-containing triazatriangulenium adlayers on Au(111): structural and spectroscopic characterization

Area of Science:

• Surface science
• Materials chemistry
• Molecular engineering

Background:

• Triazatriangulenium (TATA) molecules offer a versatile platform for functionalization.
• Azobenzene derivatives are known for their photoresponsive properties.
• Understanding molecular adsorption on surfaces is crucial for designing advanced materials.

Purpose of the Study:

• To investigate the adsorption behavior of azobenzene-functionalized TATA derivatives on Au(111) surfaces.
• To characterize the structure and orientation of these adlayers.
• To confirm the integrity of the molecules upon adsorption.

Main Methods:

• Scanning tunneling microscopy (STM) for surface imaging.
• X-ray photoelectron spectroscopy (XPS) for chemical composition analysis.
• Gap-mode surface-enhanced Raman spectroscopy (gap-mode SERS) for vibrational analysis.
• Cyclic voltammetry (CV) for electrochemical characterization.

Main Results:

• Adlayers formed by azobenzene-functionalized TATA derivatives on Au(111) were successfully prepared and characterized.
• Chemical analysis confirmed the presence of expected functional groups and the TATA core.
• Spectroscopic and electrochemical data verified the intactness of the azobenzene moieties.
• The freestanding functional groups were found to be oriented perpendicularly to the TATA platform and the gold surface.

Conclusions:

• Azobenzene-functionalized TATA molecules adsorb intact on Au(111) surfaces.
• The adsorption process leads to a specific orientation of the functional groups.
• This study provides insights into the self-assembly of functional organic molecules on metal surfaces.