Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 12: 2D Materials: Session II (joint session DS/CPP/HL)

DS 12.10: Talk

Tuesday, March 13, 2018, 12:00–12:15, H 2032

Ab Initio Study of the Electronic and Optical Properties of Organic-Inorganic two-dimensional Perovskites: The Role of Many-Body Effects — •Maurizia Palummo¹ and Giacomo Giorgi² — ¹INFN and Dip. Fisica University of Roma "Tor Vergata" Via della ricerca scientifica 1 Rome Italy — ²Dip. Ing. Civile e ambientale Univ. Perugia Italy

Organic-Inorganic Halide Perovskites (OIHPs) represent the most relevant breakthrough in the last decade in photovoltaics (PV) Despite the many attractive features, some serious issues remain that prevent their usage in device mass production, such as the fast air/moisture induced degradatio. For this reason, in the last years two-dimensional Ruddlesden-Popper perovskites (2D-RPOIHPs) have emerged as an alternative to 3D bulk for their superior photo- and chemical-stability coupled with high-performance opto-electronic properties and an enhanced hydrophobic nature of the organic part. While the experimental interest towards this 2D class of materials is nowadays well assessed, ab-initio studies focusing on the role of many-body effects are very limited. By means of a coupled GW plus BSE approach on top of DFT-KS simulations, we here study the electronic and optical properties of a 2D-RPOIHP, as a single sheet and also as a periodic QW. A giant band-gap renormalization of the electronic band-gap and the formation of a strongly bound almost 2D excitons are observed. The relationship between the number of layers is discussed.