Séminaire IPCMS présenté par : Prof. Yousoo KIM 

Orateur: Prof. Yousoo KIM  (Surface and Interface Science Lab., Riken, Japan and Center for Quantum Conversion Research, IBS Gwangju, Korea)

Résumé : Energy conversion at the molecular scale is governed by the interplay of electronic, vibrational, and optical degrees of freedom, often through processes that remain hidden in ensemble-averaged measurements. In this talk, I will discuss our efforts to visualize and understand such processes at the level of individual molecules by combining scanning probe microscopy with optical and ultrafast spectroscopy.

I will first introduce how atomic-scale junctions can be used not only to image molecules, but also to probe their excited states, charge-transfer processes, and energy-dissipation pathways with unprecedented spatial resolution. Particular emphasis will be placed on single-molecule exciton dynamics, photocurrent generation, and vibration–phonon coupling at surfaces. I will then discuss our recent development of ultrafast THz-driven scanning tunneling microscopy, which provides access to excited-state dynamics with simultaneous atomic-scale spatial and picosecond temporal resolution.

These studies illustrate how local probes can reveal the elementary pathways through which energy is absorbed, converted, transported, and dissipated in individual quantum systems, providing a microscopic basis for understanding and ultimately controlling molecular-scale energy conversion.

Séminaire DMO présenté par : Ivan Khariushin

Ivan Khariushin (ICS, postdoctorant équipe SAMS)

Résumé: The proposed project addresses the bottlenecks of quantum state initialization and coherence by developing optically addressable, photogenerated high spin states. By coupling organic chromophores with paramagnetic transition metal and lanthanide centers or with stable organic radicals, this project aim to study Enhanced Intersystem Crossing (EISC) to achieve non-thermal spin hyperpolarization upon pulsed optical excitation. The use of a modular assembly strategy, which combines covalent and supramolecular linkers, allows systematical design and investigation of spin properties-structure realtionships in such systems »

Séminaire DSI présenté par : Professeure Safae AAZOU

Speaker : Professeure Safae AAZOU (Université Mohammed V de Rabat Maroc)

Abstract: Tandem solar cells can exceed the efficiency limits of single-junction devices. In this study, we investigate the use of TiO₂ buffer layer as an alternative to CdS in kesterite/c-Si tandem solar cells through combined optical and electrical simulations. The results show that TiO₂ reduces parasitic absorption and interface recombination, leading to improved optoelectronic performance. An optimized CZTGeS/c-Si tandem structure achieved an efficiency close to 20%. These findings highlight the potential of TiO₂ buffer layers for developing efficient and environmentally friendly kesterite/silicon tandem solar cells.

Pour tout contact : Dris Ihiawakrim (0388107015 – dris.ihiawakrim@ipcms.unistra.fr)