Nanostructures are characterized by their high surface-to-volume ratio. Unsaturated surface atoms tend to rearrange their position in order to saturate the dangling bonds and minimize the surface energy. Such a reconstruction penetrates deep inside the nanostructure and determines, to a large extent, the morphology of the material. Solvent and surface attached ligands modify the surface energy and exert a strong influence on the atomic structure of the nanomaterial, which in turn, defines the electronic and optical structure of the material. Furthermore, surface attached ligands modify important properties of nanomaterials, including photophysics, charge transport, catalysis and magnetism. Tayloring nanostructures’ character by means of surface attached ligands has aroused the interest of chemists and physicists. Chemical functionalization has been proven to be very useful in designing materials with specific electrical and optical properties. Moreover, the application of nanomaterials in biology and medicine is based on the ability to make them water soluble and to cap them with specific surfactants in order to facilitate selective binding to target biomolecules or subcellular structures.

In this framework, our efforts are devoted to determine the role of surface attached ligands on the properties of II-VI semiconductor nanostructures. With that goal, we combine Density Functional Theory (DFT) and Time Dependent Denstity Functional Theory (TD-DFT) calculations to unravel the structure and optoelectronics of the models considered. We are particularly interested on the interaction energy between organic molecules and II-VI clusters. These calculations could pave the way for the ad hoc design of ligands with affinity toward nanomaterials. Furthermore, we want to investigate the effect of such surface ligands on the optical properties of nanostructures.

Recent publications on the field:

  • J. M. Azpiroz, J. M. Matxain, I. Infante, X. Lopez, J. M. Ugalde “A DFT/TDDFT Study on the Optoelectronic Properties of the Amine-Capped Magic (CdSe)13 Nanocluster“, accepted for publication in Physical Chemistry Chemical Physics.
  • J. M. Azpiroz, I. Infante, X. Lopez, J. M. Ugalde, F. De Angelis, “A first-principles study of II-VI (II = Zn; VI = O, S, Se, Te) semiconductor nanostructures“, Journal of Materials Chemistry, vol.22, iss.40, p.21453-21465, (2012) . DOI: 10.1039/C2JM33744D
  • J. M. Azpiroz, X. Lopez, J. M. Ugalde, I. Infante, “Modeling Surface Passivation of ZnS Quantum Dots“, The Journal of Physical Chemistry C, vol.116, iss.4, p.2740-2750, (2012) . DOI: 10.1021/jp209863p
  • J. M. Azpiroz, E. Mosconi, F. De Angelis, “Modeling ZnS and ZnO Nanostructures: Structural, Electronic, and Optical Properties“, The Journal of Physical Chemistry C, vol.115, iss.51, p.25219-25226, (2011) . DOI: 10.1021/jp2083709