Size-dependent electronic structure of rutile TiO2 quantum dots

We present results of our theoretical calculation on structural and electronic properties of passivated rutile (TiO2)n quantum dots as a function of the size of the dots. Structural properties viz. geometry, bond lengths, binding energies and electronic properties such as HOMO–LUMO gap, density of states and HOMO, LUMO densities have been analyzed. The passivation of surface Ti with –OH groups and surface O atoms with –H atoms increases the HOMO–LUMO energy gap of the clusters. Our study reveals that the HOMO densities for rutile quantum dots are delocalized throughout the whole cluster while that of LUMO are strongly localized on a few surface Ti atoms.