Self-assembled polythiophene monolayer on gold surface

Poly(3-dodecylthiophene) monolayer was self-assembled on the gold surface b y immersion of gold substrate into the solution of polythiophene. The peak of the photoluminescence (PL) spectra of the monolayer sample was redshifte d compared to those of a bulk polythiophene. By exciting the sample with li nearly-polarized light incident obliquely to the sample, strong anisotropy in the fluorescence intensity was observed as the polarization direction of the pump beam was rotated. From this result, the tilt angle of the thiophe ne ring with respect to the surface normal of the gold substrate was measur ed.