Molecular rearrangement and optical property changes of p-sexiphenyl vacuum-deposited film induced by rubbing

Structural and optical property changes of p-sexiphenyl (6P) films induced by rubbing were investigated. 6P molecules vapordeposited on a fused silica glass adsorbed obliquely but had no in-plane orientation. After rubbing, the film surface became smooth and the electron microscopic analysis revealed that the longitudinal direction of the 6P molecules is parallel to the substrate surface and oriented uniaxially along the rubbing direction. The absorption spectrum changed corresponding to the orientation change of the 6P molecules. The 6P molecules grew homoepitaxially on the rubbed film, and the film exhibited a high anisotropic optical property (dichroic ratio: 9.6) when deposition was performed at a low substrate temperature (RT) and a high de position rate (5 nm/min).