Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 48: Focus: Fundamental Physics of Perovskites I - organized by Lukas Schmidt-Mende and Vladimir Dyakonov
CPP 48.1: Topical Talk
Mittwoch, 14. März 2018, 15:00–15:30, C 130
Long lifetimes and small phonon energies in metal-halide perovskite solar cells — •Thomas Kirchartz1,2, David Egger3, and Uwe Rau1 — 1IEK5 Photovoltaik, Forschungszentrum Jülich GmbH, 52428 Jülich — 2Faculty of Engineering and CENIDE, University of Duisburg-Essen, Carl-Benz-Str. 199, 47057 Duisburg, Germany — 3Institute of Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
Lead-halide perovskite solar cells have remarkably high open-circuit voltages and relatively long lifetimes as determined from e.g. transient photoluminescence or transient microwave photoconductivity. These long lifetimes lead to fairly good charge carrier collection properties and in addition a high internal luminescence yield that makes these materials suitable for photovoltaics and other optoelectronic applications. One agreed-upon reason for these long lifetimes is the defect tolerance of lead-halide perovskites and the subsequently low density of deep defects in the material. However, various other potential explanations for long lifetimes and high open-circuit voltages have been brought forward. Among them are the existence of an indirect band gap, low effective masses or polaronic effects. Here, we recall the classical theories for non-radiative recombination via emission of multiple phonons, which predict the capture cross sections as a function of microscopic parameters such as the phonon energy, the deformation potential constant and the frequency dependent permittivity. Based on these theories we discuss the impact of low phonon energies and the strongly frequency dependent permittivity on recombination.