First-principles molecular dynamics simulations of ligand-passivated cadmium selenide quantum dots*

Semiconductor quantum dots (QD) are heterogeneous ligand-passivated nanostructures used in photovoltaic cells and light emitting devices. Predictions of the optoelectronic properties of QDs are challenging as most synthesis methods yield broad size distributions; in addition, in most cases only indirect and partial information is available from experiments on the structure of the QD/ligand interface. Recently, small ligand terminated cadmium selenide clusters, with a known number of core atoms, were synthesized [1], providing ideal test-beds to cross-validate experiments and theory. Using the experimentally determined QD core structures, we conducted first-principles molecular dynamics simulations at finite temperatures to uncover the effects of the passivating ligand layer on the structural and optoelectronic properties of the clusters.
[1] Alexander N Beecher et al., JACS 136, 10645 (2014)