Modeling the structure and electronic properties of TiO₂ nanoparticles

A self-consistent tight-binding method and density functional theory were used to study structures and electronic properties of anatase nanoparticles. Full geometry optimization resulted in both surface relaxation and a slight overall contraction of the nanoparticles. Analyzing electronic properties using electron localization function and Mulliken populations, we found nonbonding electrons at the edges and corners of the nanoparticle. The results of tight-binding and density functional theory calculations are in good agreement, suggesting the tight-binding scheme to be a useful tool for studies of larger nanoparticles in the range of hundreds to thousands of atoms. The self-consistent tight-binding results on nanoparticles of sizes up to 1365 atoms and some structural, electronic, and energetic trends as a function of nanoparticle size are also reported.