Ultrafast spectroscopic techniques provide a multidimensional perspective on photo-induced processes in excitonic materials by offering spectral, temporal, and/or spatial resolution. This allows for a comprehensive analysis of processes, including exciton generation, relaxation, recombination, diffusion, dissociation, intersystem crossing, coherent coupling, energy transfer, charge transport in solid films, and spin-selective dynamics such as chirality induced spin selectivity. Mechanistic understanding of these phenomena, especially in complex media such as semiconductor heterostructures, hybrid materials, and chiral materials, is crucial for advancing applications such as LEDs, photovoltaics, photoredox reactions, lasing, and opto-spintronic applications.
The method spectrum for these investigations is vast and includes pump (dump/pump-) probe transient absorption spectroscopy (UV-vis, XUV, IR, X-ray, THZ), multidimensional electronic and vibrational spectroscopy, and time-resolved impedance, cathodoluminescence, chiroptical and microscopy techniques. #SpecEx highlights ultrafast spectroscopic investigations of the photophysical, photochemical, and optoelectronic properties of excitonic materials, novel ultrafast methods, and their respective interpretations and tools.
- Charge separation in hybrid materials for photoredox reactions
- Exciton diffusion/dissociation in assembled nanocrystal films
- Stimulated/amplified emission and optical gain for lasing applica
- Chirality in excitonic materials: CISS, emission, chiral catalysis
- Non-linear optical phenomena
- Spectroscopic data evaluation (computational/data science)
- Time resolved measurements under in situ/operando conditions
- Novel spectroscopic methods
Sascha is a Tenure-Track Assistant Professor in Physical Chemistry and Head of the Laboratory for Energy Materials at EPFL (Switzerland), while he is also maintaining strong ties with the Harvard community and in particular Winthrop House which he regularly visits as NRT and SCR member.
His team employs light-matter interactions to understand the next generation of soft semiconductors with the overarching goal of maximizing energy efficiency for a sustainable future by unlocking applications ranging from flexible light-weight solar cells & displays all the way to entirely new applications in quantum information processing.
Previously, he was a research group leader and Rowland Fellow at Harvard University. Before starting his lab at Harvard, Sascha studied Chemistry at Heidelberg University (Germany) and completed a PhD in Physics at the University of Cambridge (UK), where he subsequently worked as EPSRC Doctoral Prize Fellow.
James Utterback’s research focuses on ultrafast optical spectroscopy and microscopy of energy relaxation and transport in materials for optoelectronic, photochemistry, and phase change applications.
CNRS Researcher | Researcher; Institute of Nanosciences of Paris; Sorbonne University | 2023 – present
Postdoctoral Fellow | Beckman Postdoctoral Fellow; University of California, Berkeley | 2019 – 2022
PhD in Chemistry | NSF Graduate Research Fellow; University of Colorado, Boulder | 2013 – 2018
B.S. in Physics | Goldwater Scholar & Undergraduate Research Fellow; University of Oregon | 2007 – 2011
Maria Wächtler studied Chemistry at the Friedrich Schiller University in Jena where she also received her PhD in 2013. After a postdoctoral period at Leibniz Institute of Photonic Technology Jena (Leibniz-IPHT), she was appointed head of work group Ultrafast Spectroscopy in the department Functional Interfaces in 2015 and since 2020 she is head of work group Quantum Confined Nanostructures at Leibniz-IPHT. Her research focuses on the design of systems for light-driven water splitting based on colloidal semiconductor nanostructures and the investigation of function determining interactions and light-driven processes by (time-resolved) spectroscopy.