Regensburg 2019 – wissenschaftliches Programm
HL 45.9: Poster
Donnerstag, 4. April 2019, 18:30–21:00, Poster E
Stable hybrid organic-inorganic halide perovskites for photovoltaics from ab-initio high-throughput calculations — •Sabine Körbel1, Miguel A. L. Marques2, and Silvana Botti1 — 1Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Germany — 2Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Germany
Hybrid perovskites, such as methylammonium lead iodide, have revolutionized research on solar cells in the past years. Well known instability and toxicity issues restrain however the large-scale application of these perovskites in commercial photovoltaic technology. It is therefore crucial to find chemical substitutions which stabilize these and other lead-free perovskites, preserving at the same time their excellent absorption and charge-transport properties. Using density-functional theory, we screened the periodic table of the elements for perovskites with the composition A+B2+X3−, where A is a molecular organic cation, B is a divalent element, and X is a halogen. For the molecular cation, we vary the molecule size from sulfonium (H3S, very small) to tert-butylammonium (C4NH12, very large). All thermodynamically stable hybrid perovskites were then further characterized by calculating their band gaps and effective masses, to identify the most promising candidates for further experimental and theoretical characterization. We find that the substitution of the organic molecule is the most promising way to enhance thermodynamic stability, while there is no optimal replacement for lead or Sn, unless one considers partial substitution or alloying.