Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 68: Electronic Structure Theory: Many-Body Effects
O 68.9: Poster
Mittwoch, 18. März 2015, 18:15–21:00, Poster A
Size-dependent optical gaps of Cu chalcogenide nanocrystals from GW and the Bethe-Salpeter equation — •Sabine Körbel1,2, Miguel Alexandre Lopes Marques1,2,3, and Silvana Botti4,2,3 — 1Martin-Luther-Universität Halle-Wittenberg, Germany — 2Université Claude Bernard Lyon 1, France — 3European Theoretical Spectroscopy Facility — 4Friedrich-Schiller-Universität Jena, Germany
In semiconductor nanocrystals, quantum confinement, which opens the optical gap with decreasing nanocrystal size, allows to tune the optical absorption edge. Hence, nanoparticles of different sizes may be used in multilayer thin-film solar cells, with each layer consisting of nanocrystals of a different size, absorbing light at a different frequency, therefore enhancing the overall efficiency of the solar cell, all the while using one and the same photovoltaic absorber material. Here we present size-dependent optical gaps of nanocrystals of Cu2ZnSn(S,Se)4 [CZTS(e)], an earth-abundant semiconductor with a direct optical gap suitable for solar-cell absorbers, calculated with GW and the Bethe-Salpeter equation, and compared to experimental data, where available.