The chiroptical properties of chiral substituted poly[3-((3S)-3,7-dimethyloctyl)thiophene] as a function of film thickness

Circular dichroism (CD) and circular polarization of the luminescence (CPL) of spin coated films of chiral, regioregular poly[3-((3S)-3,7-dimethyloctyl)thiophene] are investigated as a function of their thickness (50–500 nm). The dissymmetry factors for absorption (gabs) and emission (glum) do not significantly depend on the film thickness and can therefore be considered as an intrinsic property of the material. This is consistent with the circular polarization in absorption and emission originating on a molecular level from a difference in the probability for absorption and emission of left and right handed photons at the site of the optical excitation. Graphical abstract The dissymmetry factor for circular polarization in absorption and emission of polythiophene 1 is practically independent of the thickness of the film and can therefore be regarded as an intrinsic property of the material