Quantum 2025 – wissenschaftliches Programm
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MON: Monday Contributed Sessions
MON 23: Poster Session: Fundamental Aspects and Model Systems
MON 23.37: Poster
Montag, 8. September 2025, 18:30–20:30, ZHG Foyer 1. OG
Illumination dependent hot polaron photovoltaics in strongly correlated perovskite manganites — •Annika Dehning, Birte Kressdorf, Jörg Hoffmann, and Christian Jooss — Institute of Materials Physics, University of Göttingen, Germany
Highly correlated materials offer new pathways to stabilize hot-carriers after optical excitation and thus might enable overcoming the Shockley-Queisser (SQ) limit. In metal-oxide perovskites excited polaronic states can be stabilized up to ns-lifetime through the enhanced coupling between phonons and charges in the charge/orbital (CO) ordered state. Understanding the mechanisms behind hot polaron photovoltaics (PV) challenges because of the complex interplay between electronic degrees of freedom and structure. It requires knowledge about the cold quantum ground state and how it is affected by lattices, temperature and excitations. Light induced excitations are studied here in dependence of temperature, photon energy and power in Pr1−xCaxMnO3 and Ruddlesden-Popper Pr1−xCa1+xMnO4 (RP-PCMO). Single-crystalline epitaxial thin films are prepared on Nb:SrTiO3 substrates with ion beam sputtering. XRD, AFM, SEM, EDX and TEM are employed to characterize the films, their ordering and the p-n junction. It is demonstrated that the PV response correlates with the appearance of CO order and it is measured up to 320K in RP-PCMO. The characteristic PV-parameters reveal spectral and power density dependencies that do not follow the SQ-theory. An approach to describe the PV-response based on hot carrier contributions via scaling laws is presented.
Keywords: Correlated materials; Photovoltaics; Energy conversion; Polaron; Thin films