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

Abstract

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 carried out at Diamond B23 beamline using the synchrotron radiation electronic circular dichroism imaging (SR‐ECDi) facility. The experimental results support the hypothesis that the non‐reciprocal circularly polarized absorption observed in these materials is due to the combined linear dichroism and linear birefringence contributions. The mapping at 50‐µM spatial resolution revealed that several species coexist in the mesoscopic chiral domains likely due to different aggregated phases, which were identified in the films by SR‐ECDi but could not be detected with benchtop ECD instruments.

Keywords

• benzo[1,2‐b:4,5‐b’]dithiophene
• circular dichroism imaging
• oligothiophenes
• synchrotron radiation
• thin films