Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 70: Focussed Session: Frontiers of Electronic Structure Theory - Non-equilibrium Phenomena at the Nano-scale VI
O 70.8: Vortrag
Donnerstag, 3. April 2014, 12:30–12:45, TRE Ma
Solar nanocomposites with complementary charge extraction pathways for electrons and holes: Si embedded in ZnS — •Stefan Wippermann1, Marton Vörös2, Adam Gali3, Francois Gygi2, Gergely Zimanyi2, and Giulia Galli2 — 1Max-Planck-Institute for Iron Research, Düsseldorf — 2University of California, Davis — 3Budapest University of Technology and Economics
We propose that embedding silicon nanoparticles (NP) into amorphous, non-stoichiometric ZnS leads to promising nanocomposites for solar energy conversion. Using ab initio molecular dynamics simulations we show that upon high temperature amorphization of the host chalcogenide, sulfur atoms are drawn to the NP surface. We found that the sulfur content may be engineered to form a type II hetero-junction, with complementary charge transport channels for electrons and holes, and that sulfur capping is beneficial to lower the nanoparticle gap, with respect to that of NPs embedded in oxide matrices. Our analysis was conducted using density functional theory with local and hybrid functionals and many body perturbation theory at the GW level.