With the current urgency for green and renewable energies, photovoltaic (PV) technologies seem to be a partially good candidate for this transition. In the scope of the unending battle in improving photovoltaic efficiencies a better understanding of the photophysical processes in PV materials can lead to better device engineering. In collaboration with the LPI (Laboratory of Photonics and Interfaces, EPFL) I conducted a study of the charge carrier dynamics in 2D hybrid perovskites using different spectroscopic techniques such as femtosecond transient absorption and pump probe terahertz spectroscopy to understand the effect of increasing the size of the spacer within these types of samples. These samples show the characteristic signal of a short lived photoinduced stark effect which was assigned to a charge transfer exciton¹. To conclude my talk, I will shortly introduce my thesis project. The subject is the use of Thermally Assisted Delayed Fluorescence (TADF) molecules to overcome the roll-off in organic continuous wave lasers.

1. « The Impact of Spacer Size on Charge Transfer Excitons in Dion–Jacobson and Ruddlesden–Popper Layered Hybrid Perovskite » George C. Fish, Aaron T. Terpstra, Algirdas Dučinskas, Masaud Almalki, Loï C. Carbone, Lukas Pfeifer, Michael Grätzel, Jacques-E. Moser, and Jovana V. Milić. The Journal of Physical Chemistry Letters 2023 14 (27), 6248-6254

Contact: Loic Mager <mager@ipcms.unistra.fr>