P5 Ultrafast Phenomena at the Nanoscale
About the Programme
Photoinduced Exciton and Charge Transport (ET and CT) controls fundamental processes occurring in plants and bacteria, such as photosynthesis, photo-oxidation, electronic transport and molecular damage. They are also at the heart of emerging technologies, such as those based on photovoltaic and optoelectronic devices, molecular wires, molecular junctions, polymer-based transistors, photocatalysis and artificial photosynthesis, all of them the object of thorough investigations at IMDEA Nano. The common denominator for ET/CT processes is the absorption of light, which produces electron-hole pairs (or excitons) that can separate along the material, thus generating an electric current. The initial electron-hole dynamics is very fast: it occurs on a time scale ranging from hundreds of attoseconds to a few femtoseconds. At longer times, from several tens of fs to picoseconds or even nanoseconds, the coupling with nuclear motion can substantially alter the generated electric current and even suppress it due to decoherence effects.
The Programme focuses on the study of ultrafast phenomena with simultaneous high temporal and spatial resolutions. This is achieved by the combination of in-house scanning tunnelling microscopes, transient absorption set ups, and femto-chemistry using ultrashort pulses with extend theoretical tools (to interpret and guide the new experiments). Additionally, extremely intense X-ray flashes at European XFEL are used to elucidate some fundamental aspects. This programme is in close collaboration with research programmes P1,P2, and P4. Our goal is to understand the mechanisms of ET/CT and eventually control them, tracking electronic motion from the very first femtosecond to the picosecond, and this with, ideally, subfemtosecond time resolution. The access to both the nanometer length scale – small enough to see the motion of small molecules – and the femtosecond time scale – fast enough to resolve the vibration of molecular bonds- be able to watch structural changes and electronic energy shifts, as chemical reactions take place in solution or on catalytic surfaces, resulting in the long-sought ‘molecular movie’.
Programme Manager: Prof. Johannes Gierschner.