Mainz 2026 – scientific programme

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MO: Fachverband Molekülphysik

MO 19: Poster – Contributions to SYLC

MO 19.1: Poster

Wednesday, March 4, 2026, 17:00–19:00, Philo 1. OG

Femtosecond transient circular dichroism spectroscopy and transient circularly polarized luminescence of chiral copolymer thin films — •Kawon Oum and Thomas Lenzer — University of Siegen, Physical Chemistry 2, Adolf-Reichwein-Str. 2, 57076 Siegen

We have recently developed an experimental methodology enabling the simultaneous recording of transient absorption (TA) and transient circular dichroism (TrCD) responses of photoexcited systems across the ultraviolet-visible spectral range (260-700 nm) with a time resolution of ca. 100 fs. This approach has been applied to chiral polyfluorene copolymer thin films exhibiting intrinsic [1] and induced supramolecular chirality,[2,3] where exceptionally strong circular dichroism signals of up to 16000 mdeg and dissymmetry factors approaching 0.7 were observed. Complementary steady-state and transient circularly polarized luminescence (TrCPL) studies reveal a remarkable sign inversion of both CD and CPL signals with increasing film thickness and annealing temperature, attributed to structural reorganization within the chiral supramolecular phase.[4] The pronounced chiroptical activity of these films highlights their potential for optoelectronic applications, particularly in OLEDs with intrinsic circularly polarized emission.

[1] M. Morgenroth et al., Nat. Commun. 2022, 13, 210. [2] M. Morgenroth et al., Angew. Chem. Int. Ed. 2022, 61, e202203075. [3] D. Gust et al., Sci. Rep. 2024, 14, 12694. [4] D. Gust et al., ChemPhotoChem 2025, e202500196.

Keywords: Femtosecond transient CD spectroscopy; Transient CPL spectroscopy; Chiral copolymer thin films; Supramolecular chirality; Müller matrix spectroscopy