News

Galli Group uses first principles calculations to predict promising solar nanocomposite materials

A publication from Pritzker School of Molecular Engineering was featured on the March 14, 2014, cover of Physical Review Letters.

The Galli Group's paper proposes new ways to engineer efficient pathways for electrons and holes extraction in nanostructured semiconductors. This is an essential prerequisite for the efficient interconversion of solar energy into electricity when using semiconductors. The predictions presented in the paper were obtained using a combination of ab initio molecular dynamics simulations and electronic structure calculations.

The team predicted that by embedding silicon nanoparticles (NPs) into amorphous, non-stoichiometric II-VI chalcogenides, e.g. ZnS, one may engineer the sulfur content of the matrix so as to form a type II hetero-junction between the NP and ZnS. The bottom of the conduction band turns out to be localized on the Si NP and the top of the valence band is instead mostly localized on the chalcogenide host. This spatial separation of electron and hole states gives rise to complementary charge transport channels, which avoid undesired recombination.

The work presented in the paper resulted from a collaboration between Prof. Giulia Galli's group and the groups of Prof. Zimanyi and Prof. Gygi at University of California, Davis.