Universität zu Köln

Bernhardt, Robin ORCID: 0000-0002-0296-8731 (2024). Dynamic, Excitonic and Structural Properties of Squaraine-based Molecular Aggregates. PhD thesis, Universität zu Köln.

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Abstract

Organic electronics are at the forefront of modern optoelectronic technologies. Their photophysical properties are determined not only by the organic molecules chosen, but also by their intermolecular interactions in an aggregated phase. These interactions have multiple fingerprints on ultrafast timescales, which can lead to deeper understanding of these materials and higher performance devices. The scope of this work covers the ultrafast and steady-state photophysical and excitonic properties of aggregates and blends based on the squaraine molecules nBSQ and ProSQ-C16, targeted for photodetection, photovoltaic and chiroptical applications. In detail, we utilized ultrafast transient absorption spectroscopy and steady-state absorption and emission spectroscopy, employing both experimental and simulation approaches. The use of a white light supercontinuum probe in transient absorption enabled us not only to study the lifetime of excitons, but also reveal their physical nature. Complementary to the experimentally obtained spectra, lightweight simulations of both steady-state and ultrafast transient spectra were employed. This approach unfolded the underlying large-scale aggregate structure, revealing the structure-property relationships in squaraine-based molecular aggregates.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Bernhardt, Robin bernhardt@ph2.uni-koeln.de orcid.org/0000-0002-0296-8731 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-732789
Date:	5 March 2024
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Außeruniversitäre Forschungseinrichtungen > MPI for Biology of Ageing
Subjects:	Physics
Uncontrolled Keywords:	Keywords Language Ultrafast Spectroscopy English Molecular Aggregation English Exciton Physics English
Date of oral exam:	5 June 2024
Referee:	Name Academic Title van Loosdrecht, Paul H.M. Professor Pchenitchnikov, Maxim S. Professor
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/73278