title: Solar nanocomposites with complementary charge extraction pathways for electrons and holes: Si embedded in ZnS.
abstract: We propose that embedding silicon nanoparticles (NP) into amorphous, nonstoichiometric 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 find that the sulfur content may be engineered to form a type II heterojunction, 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 is conducted using density functional theory with local and hybrid functionals and many body perturbation theory at the GW level.
authors.affiliation: Interface Chemistry and Surface Engineering Department, Max-Planck-Institute for Iron Research GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany and Chemistry Department, University of California, Davis, California 95616, USA and Physics Department, University of California, Davis, California 95616, USA.
authors.forename: Stefan
authors.initials: S
authors.lastname: Wippermann
authors.affiliation: Chemistry Department, University of California, Davis, California 95616, USA and Physics Department, University of California, Davis, California 95616, USA.
authors.forename: Márton
authors.initials: M
authors.lastname: Vörös
authors.affiliation: Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary and Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary.
authors.forename: Adam
authors.initials: A
authors.lastname: Gali
authors.affiliation: Department of Computer Science, University of California, Davis, California 95616, USA.
authors.forename: Francois
authors.initials: F
authors.lastname: Gygi
authors.affiliation: Physics Department, University of California, Davis, California 95616, USA.
authors.forename: Gergely T
authors.initials: GT
authors.lastname: Zimanyi
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Illinois 60637, USA.
authors.forename: Giulia
authors.initials: G
authors.lastname: Galli