Manna Liberato, Wang Lin Wang, Cingolani Roberto, Alivisatos A Paul
National Nanotechnology Lab of INFM, Via Arnesano Km 5, 73100 Lecce, Italy.
J Phys Chem B. 2005 Apr 7;109(13):6183-92. doi: 10.1021/jp0445573.
Equilibrium geometries, surface energies, and surfactant binding energies are calculated for selected bulk facets of wurtzite CdSe with a first-principles approach. Passivation of the surface Cd atoms with alkyl phosphonic acids or amines lowers the surface energy of all facets, except for the polar 000 facet. On the nonpolar facets, the most stable configuration corresponds to full coverage of surface Cd atoms with surfactants, while on the polar 0001 facet it corresponds only to a partial coverage. In addition, the passivated surface energies of the nonpolar facets are in general lower than the passivated polar 0001 facet. Therefore, the polar facets are less stable and less efficiently passivated than the nonpolar facets, and this can rationalize the observed anisotropic growth mechanism of wurtzite nanocrystals in the presence of suitable surfactants.
采用第一性原理方法计算了纤锌矿CdSe选定体相晶面的平衡几何结构、表面能和表面活性剂结合能。用烷基膦酸或胺对表面Cd原子进行钝化可降低所有晶面的表面能，但极性的0001晶面除外。在非极性晶面上，最稳定的构型对应于表面Cd原子被表面活性剂完全覆盖，而在极性的0001晶面上，它仅对应于部分覆盖。此外，非极性晶面的钝化表面能通常低于钝化的极性0001晶面。因此，极性晶面比非极性晶面稳定性更低且钝化效率更低，这可以解释在合适表面活性剂存在下纤锌矿纳米晶体观察到的各向异性生长机制。
