Analysis of Molecular Orientation and Conformation of Poly(3-hexylthiophene) Thin Films on Silicon by Infrared p-Polarized Multiple-angle Incidence Resolution Spectrometry

Abstract

Abstract Infrared (IR) p-polarized multiple-angle incidence resolution spectrometry (p-MAIRS) has been employed for the first time to reveal the molecular orientation in two different poly(3-hexylthiophene) (P3HT) thin films having face-on and edge-on orientations. The C–H out-of-plane deformation vibration mode (ca. 820 cm−1) of the thiophene ring is found to be highly localized on the ring, which is quite useful for molecular orientation analysis coupled with IR p-MAIRS. On the other hand, the C–H stretching vibration region is useful for determining the molecular order, conformation, and folding of the hexyl chain via MAIRS dichroism.