Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 7: Hybrid and Perovskite Photovoltaics I (joint session CPP/DF/DS/HL, organized by CPP)
CPP 7.8: Vortrag
Montag, 7. März 2016, 17:00–17:15, H38
The Importance of Hydrogen Defect Migration in Organic-Inorganic Perovskites — •David A. Egger1, Leeor Kronik1, and Andrew M. Rappe2 — 1Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel — 2The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
Solar cells based on organic-inorganic perovskites have been proven to be remarkably efficient in recent years. However, they exhibit hysteresis in the current-voltage curves, and their stability properties, especially in the presence of water, are problematic. Both issues are possibly related to ionic diffusion phenomena occurring in the hybrid perovskite material. Using first-principles calculations based on density functional theory, we study the properties of an important defect in hybrid perovskites - interstitial hydrogen.[1] We show that differently charged defects occupy different sites in the hybrid perovskite crystal, which allows for an ionization-enhanced defect migration following the Bourgoin-Corbett mechanism. Our analysis further highlights the structural flexibility of organic-inorganic perovskites, where successive displacements of iodide combined with hydrogen bonding enables proton diffusion with low migration barriers. These findings indicate that hydrogen species can be highly mobile in hybrid perovskite solar cells and thus relevant for their performance.
Angew. Chem. Int. Ed. 54, 12437 (2015)