Revealing the Ultrafast Charge Carrier Dynamics in Two-dimensional Perovskites

• Applicant: Stephan Schäffer
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 577300573

Two-dimensional lead-halide Ruddlesden–Popper perovskites (2DPK) are an emerging class of semiconductor with a unique set of properties that might give them a decisive edge over established materials for low cost, integrated optoelectronic devices. Yet, understanding of the ultrafast photo carrier dynamics in 2DPK is limited due to a lack of suitable methods to clearly differentiate between excitons and unbound electron-hole (e-h) pairs and quantify their densities. Using ultrabroadband THz spectroscopy and supported by microscopic modelling, I aim to probe low-energy, internal quantum transitions 1s-np of photoexcited excitons in 2DPK to unambiguously quantify and trace the generation and annihilation of excitons in 2DPK. Moreover, ultrabroadband THz spectroscopy is equally sensitive to unbound e-h pairs and may enable a comprehensive insight into the photo carrier dynamics and many-body interactions in 2DPK. Establishing this method will help leveraging the potential of 2DPK for various optoelectronic applications.

• DFG Programme: WBP Fellowship
• International Connection: France
• Host: Dr. Juliette Mangeney