Computational-chemistry Research Projects

Functionalized metal oxide nanoparticles

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A nanoparticle The term nanoparticle refers to particles of dimensions 1-100 nm, and matter in this form may possess mechanical, optical and electronic properties that differ significantly from when present in its molecular or bulk forms. Metal-oxide nanocrystalline particles are attracting interest due to their usage and potential capabilities as for example dye pigments, heterogeneous catalysts, chemical sensors and biomarkers, light-emitting devices and photodetectors, and solar cell components.

LUMO of isonicotinic acid chemisorbed on a ZnO surface HOMO of isonicotinic acid chemisorbed on a ZnO surface The properties of the nanocrystals can be further modified by capping the surface with an organic molecular layer, which interacts with surface states of the metal oxide. The adsorbed molecular layer may in turn contain functional groups that carry out a desired action, for example attachment to a specific target or absorption of light of a certain wavelength.

In this project, we study nanoparticles of semiconducting materials such as ZnO, TiO2, RuO2, Y2O3, Gd2O3, and CoO2, their interactions with organic and bioorganic molecular functional groups, and chemical reactions catalysed by them.

Observed and calculated (discrete peaks) IR spectra Due to its unusual luminiscence properties, zink oxide has been at the focus of investigation to large extent. Studies are made of luminescence spectra for different organic molecules such as bensoic, nicotinic, cinnamic and oleic acid on ZnO nanoparticles in order to understand the processes involved, and of self-assembled monolayers of molecules such as mercaptopropyl trimethoxysilane (MPTMS) on ZnO surfaces. The preferred arrangement and binding mode of these are not trivial to find out experimentally, so quantum-chemical computation is a valuable tool.

Contacts:
Lars Ojamäe, Annika Lenz

Key publications:

  • ZnO nanoparticles functionalized with organic acids: an experimental and quantum-chemical study
    A. Lenz, L. Selegård, F. Söderlind, A. Larsson, P.-O. Holtz, K. Uvdal, L. Ojamäe and P.-O. Käll
    J. Phys. Chem. C 113, 17332-17341 (2009)

 

This work was supported by the Swedish Research Council and by CeNano at Linköping University.

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