Spatially resolved chiroptical study of thin films ofbenzo[1,2-b:4,5-b’]dithiophene-based oligothiophenes bysynchrotron radiation electronic circular dichroism imaging(SR-ECDi) technique

Albano, Gianluigi; Górecki, Marcin; Jávorfi, Tamás; Hussain, Rohanah; Siligardi, Giuliano; Pescitelli, Gennaro; Di Bari, Lorenzo

Spatially resolved chiroptical study of thin films ofbenzo[1,2-b:4,5-b’]dithiophene-based oligothiophenes bysynchrotron radiation electronic circular dichroism imaging(SR-ECDi) technique

Abstract

The study of the chiroptical properties of thin-film samples of two chiral benzo[1,2-b:4,5-b’]dithiophene-based oligothiophenes with optoelectronic properties was car-ried out at Diamond B23 beamline using the synchrotron radiation electronic cir-cular dichroism imaging (SR-ECDi) facility. The experimental results support thehypothesis that the non-reciprocal circularly polarized absorption observed in thesematerials is due to the combined linear dichroism and linear birefringence contribu-tions. The mapping at 50-μm spatial resolution revealed that several species coexistin the mesoscopic chiral domains likely due to different aggregated phases, whichwere identified in the films by SR-ECDibut could not be detected with benchtopECD instruments.