Molecular Structure at the Interfaces of Submonolayer Thin Films of Sexithiophene

Vibrational sum frequency generation (VSFG) spectroscopy with different polarization combinations was used to show that the average orientation of α- sexithiophene (6T) on a glass substrate for the 6T/glass interface changes with the thickness of the film. This is a result of 6T growth mechanism on glass, which was studied by AFM imaging. It was also shown that 6T on glass forms a wetting layer, and the buried interface experiences a change in environment after some critical deposition thickness, leading to a change in the orientation of the interfacial molecules.