报告题目：Attosecond spectroscopy of photovoltaics

报告人：Dr. Hugo Laurell Niels, Bohr Institute, University of Copenhagen

报告人简介：

Dr. Hugo Laurell is a postdoctoral researcher at the Niels Bohr Institute, University of Copenhagen, where he works within the Novo Nordisk Foundation Quantum Computing Programme. He also holds a part-time postdoctoral position at Lund University in the Division of Synchrotron Radiation Research. He received his PhD in Physics from Lund University, where he worked on ultrafast and attosecond spectroscopy. His research focuses on attosecond transient absorption spectroscopy of solids, with particular emphasis on ultrafast carrier dynamics, coherent phonons, and many-body interactions in semiconductors and photovoltaic materials. He has also worked on multidimensional XUV spectroscopy, photoelectron interferometry, and the development of attosecond methods for probing quantum materials. His current research interests include applying attosecond spectroscopy to quantum emitters and semiconductor platforms relevant for quantum technologies. Dr. Laurell has conducted postdoctoral research at the University of California, Berkeley and Lawrence Berkeley National Laboratory, and his work has been published in journals including Nature Photonics and Physical Review Research.

摘要：

Attosecond transient absorption spectroscopy (ATAS) provides a direct route to follow electronic and structural dynamics in semiconductors on their intrinsic time scales. In this talk, I present recent ATAS measurements on two emerging photovoltaic materials, Cu-poor Cu(In,Ga)Se2 (CIGS) and metastable p-SnS, using few-femtosecond near-infrared excitation and an attosecond extreme-ultraviolet probe. For CIGS, measurements across the Se M4,5 absorption edge reveals simultaneous carrier and lattice dynamics. Two coherent A1g phonon modes are assigned to the chalcopyrite and Cu-deficient ordered-vacancy compounds, while the XUV response disentangles electron and hole cooling. Rapid 18.6(3) fs oscillations are additionally observed and interpreted as quantum path interference between electronic conduction bands of the two phases. For p-SnS, ATAS at the Sn N4,5 absorption edge tracks carrier injection, hot-carrier cooling, recombination, and structural dynamics. The kinetics reveal a crossover from interface-limited recombination at low carrier density to carrier-carrier dominated dynamics above carrier densities of ~1020 cm-3. Coherent phonon oscillations with a period of approximately 188 fs further show coupling between electronic excitation and lattice motion. Together, these studies show how attosecond XUV spectroscopy disentangles carrier and structural dynamics, and enables the observation of electronic coherence in complex photovoltaics. 

[1] H. Laurell et al., arXiv:2506.05621 (2025). 

[2] H. Laurell et al., arXiv:2602.13886 (2026). 

报告时间：2026年7月14日 14:30（星期二）
报告地点：生命科学楼504会议室
主办单位：原子与分子物理研究所