X-ray spectroscopy characterization of azobenzene-functionalized triazatriangulenium adlayers on Au(111) surfaces.

Triazatriangulenium (TATA) platform molecules allow the preparation of functionalized surfaces with well-defined lateral spacings of freestanding functional groups. Using scanning tunneling microscopy, synchrotron-based X-ray photoelectron spectroscopy, near edge X-ray absorption fine structure spectroscopy and complementary density functional theory calculations the chemical composition and orientational order of adlayers of functionalized azobenzene containing TATA platform molecules were characterized. According to these studies the molecules are chemically intact on the surface after self-assembly from solution and exhibit a well-defined adsorption geometry where the azobenzene units are oriented almost perpendicular to the surface.