Monitoring electronic excitations in organic semiconductors with ultrafast optical pump-probe spectroscopy
Polarization, time and energy-resolved optical pump-probe spectroscopy is a well-established tool to monitor charge-carrier dynamics on ultrafast timescales. The general idea is that an optical excitation changes the linear response (“absorption”) properties of a sample which can be monitored optically, in a contactless, non-invasive fashion. Depending on the degree of complexity of the experiment, the data allow for the identification of structure-property relation. For example, spatial resolution can reveal the role of grain boundaries of effects of micro-structuring. Full polarization control enables insights into the role of delocalization and intermolecular charge transfer in crystalline samples.
In this presentation, Dr. Sangam Chatterjee, Professor at the Institute of Experimental Physics I at Justus-Liebig-University (JLU) Gießen, will cover the basics of fs-pump white-light probe spectroscopy including the experimental challenges and required control data to ensure reliable data. As an example, charge-carrier dynamics including singlet exciton fission in crystalline molecular films and their heterostructures will be discussed, including how pump-probe spectroscopy may be complemented by other time-resolved or structurally sensitive techniques.
Key learning objectives:
- Understand the concept of ultrafast optical pump-probe spectroscopy
- Comprehension of the technical requirements for a successful experiment and how it may be implemented with spatial, temporal, energy, and polarization resolution
- Gain awareness of the strengths and limitations compared to, e.g., time-resolved photoluminescence spectroscopy