Description du projet
Un «film» haute résolution de la dynamique de l’énergie photovoltaïque innovante grâce à la microscopie électronique ultrarapide
L’énergie solaire jouera un rôle essentiel dans la transition vers l’énergie verte. La technologie qui exploite cette énergie a fait des progrès colossaux au cours des sept décennies qui se sont écoulées depuis la démonstration de la première cellule solaire au silicium. Les pérovskites ferroélectriques non-centrosymétriques ont suscité un intérêt considérable pour la prochaine génération photovoltaïque, mais les mécanismes exacts à l’origine de leur énorme réponse photovoltaïque demeurent inconnus. Grâce au soutien du programme Actions Marie Skłodowska-Curie, le projet SpaceTimeFerro exploitera les impulsions électroniques ultrarapides dans un microscope électronique fonctionnant à l’échelle de la femtoseconde pour atteindre des résolutions spatiales de l’ordre du nanomètre et temporelles de l’ordre de la femtoseconde. Ce «film» haute résolution du champ électromagnétique en pleine évolution ainsi produit lèvera le voile sur l’origine de l’effet photovoltaïque principal anormal dans les oxydes ferroélectriques de structure pérovskite.
Objectif
Giant bulk photovoltaic effect in non-centrosymmetric ferroelectric materials is currently gaining tremendous research interest due to its above-bandgap photovoltage and the observed output voltage is around 3-4 orders of magnitude higher than the Si-solar cells. Hence, the ferroelectric photovoltaic response is considered the next-generation photovoltaic device. However, researchers currently lack a profound understanding of the exact mechanism of the bulk photovoltaic effect, and the proposed mechanisms are contradictory to each other. This, in turn, restricts the progress of the field towards efficient solar cells. The difficult part of finding the exact mechanism is due to ultrafast carrier dynamics and atomic relaxation times are of the order of ≈ 0.1 to 10 femtoseconds, which made it experimentally inaccessible. At present, the excellent infrastructure and facilities of my host institute dealing with the ultrafast carrier dynamics can record the meticulous dynamics in space-time resolution and hence can provide the exact mechanism towards the above bandgap photovoltage in the ferroelectric system. Therefore, through this project, we are going to investigate the origin of the anomalous bulk photovoltaic effect in perovskite ferroelectric oxides by “filming” the ultrafast photo-absorption and subsequent photo-excited carrier relaxation dynamics with femtosecond time resolution and nanometre spatial resolution using laser-driven electron microscopy. In contrast to the spectroscopic approach, ultrafast electron pulses in a femtosecond electron microscope or diffraction apparatus can provide nanometre spatial and femtosecond temporal resolutions at the same time and hence can provide a movie of evolving electromagnetic field in space and time. Based on the data generated, a comprehensive physical mechanism will be put forth, which will act as guidance for the selection and design of future ferroelectric systems for an improved photovoltaic response.
Champ scientifique
- natural sciencesphysical scienceselectromagnetism and electronicselectromagnetism
- natural sciencesphysical sciencesopticsmicroscopyelectron microscopy
- humanitiesartsmodern and contemporary artcinematography
- natural sciencesphysical sciencesopticsspectroscopyabsorption spectroscopy
- engineering and technologyenvironmental engineeringenergy and fuelsrenewable energysolar energyphotovoltaic
Programme(s)
- HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA) Main Programme
Régime de financement
HORIZON-AG-UN - HORIZON Unit GrantCoordinateur
78464 Konstanz
Allemagne