Deutsch Intern
Research group of Ingo Fischer

Time-Resolved Spectroscopy

Dynamics of π-conjugated molecules and their dimers with picosecond radiation

This project focuses on polycyclic aromatic hydrocarbons substituted with nitrogen or with nitrogen and boron. These molecules often possess photophysical properties, that make them potentially interesting for application in optoelectronic materials. We study the processes that occur in these molecules and their dimers after photoexcitation. The experiments are carried out in the gas phase in order to investigate the intrinsic properties of the molecules and dimers, without perturbation by a solvent. The results are subsequently compared with simulations performed in the group of Roland Mitric. In the dimers we focus on better understanding energy transfer processes and excimer formation in aggregates. Time-resolved spectroscopy in the picosecond (ps) range is used as an experimental method. We have established time-resolved photoelectron spectroscopy as a detection method, which we couple with modern imaging detection methods. This allows more detailed insights into the light-induced dynamics.

Currently, a laser desorption source is being developed to examine larger molecules. To convert the molecules into the gas phase, they are currently heated in a specially made oven. However, this method can cause the bonds to break, resulting in mainly fragments being transferred into the gas phase. The use of a laser desorption source prevents this issue.

Femtosecond Spectroscopy

When necessary, we carry out experiments with femtosecond time resolution in cooperation with the group of L. Poisson (CEA Saclay near Paris). supported by the Laserlab Europe program ( Our preferred methods are time-resolved photoionisation and photoelectron spectroscopy.


Recent publications:

1. Floriane Sturm, Michael Bühler, Christoph Stapper, Johannes S. Schneider, Holger Helten, Ingo Fischer, Merle I. S. Röhr
Impact of isoelectronic substitution on the excited state processes in polycyclic aromatic hydrocarbons: a joint experimental and theoretical study of 4a,8a-azaboranaphthalene
Phys. Chem. Chem. Phys., 2024, 26, 7363-7370

2. Floriane Sturm, Luca Nils Philipp, Marco Flock, Ingo Fischer, Roland Mitric
The Electronic Structures of Azaphenanthrenes and Their Dimers
J. Phys. Chem. A 2024, 128, 7, 1250–1259

3. Kevin Issler, Floriane Sturm, Jens Petersen, Marco Flock, Roland Mitrić, Ingo Fischer, Lou Barreau, Lionel Poisson
Time-resolved photoelectron spectroscopy of 4-(dimethylamino)benzethyne – an experimental and computational study
Phys. Chem. Chem. Phys., 2023,25, 9837-9845