Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 78: Hybrid and Perovskite Photovoltaics II
CPP 78.4: Vortrag
Freitag, 16. März 2018, 10:15–10:30, C 264
Exciton-dominated core-level absorption spectra of hybrid organic-inorganic lead halide perovskites — •Christian Vorwerk1,2, Claudia Hartmann3, Caterina Cocchi1,2, Golnaz Sadoughi4, Severin Habisreutinger4, Roberto Félix3, Regan Wilks3,5, Henry Snaith4, Marcus Bär3,5, and Claudia Draxl1,2 — 1Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany — 2European Theoretical Spectroscopy Facility — 3Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 14109 Berlin, Germany — 4Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom — 5Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
In a combined theoretical and experimental work, we investigate x-ray absorption near-edge spectra (XANES) from the iodine L3 and the lead M5 edge of the methyl-ammonium lead iodide (MAPbI3) hybrid inorganic-organic perovskite and its binary phase PbI2. We find that the absorption onsets are dominated by bound excitons with sizable binding energies of a few hundred meV and pronounced anisotropy. The spectra of both materials exhibit remarkable similarities, suggesting that the fingerprints of core excitations in MAPbI3 are essentially given by its inorganic component, with negligible influence from the organic groups. Our theoretical analysis allows for an insightful characterization of experimental observations in this complex material.