TiO2 nanocrystals are promising materials for photoelectrochemical water splitting. This research is based on experimental studies of TiO2 anatase thin films doped by a cobalt ion ingrained in the surface and functionalized on top of the surface. Specifically, by studying the binding pattern, we hope to find a connection of the electronic properties to the cobalt ion dopant location on the surface. Computational studies can be a unique tool revealing details of surface chemistry unavailable through direct measurements. On a much grander scale, it is our hope that this research will help steer research towards new photoelectrochemical solar cells.Spin polarization is taken into consideration to calculate the density of states, optical absorption spectra, and partial charge densities. While the surface ingrained doped model does not show much difference between alpha and beta electrons in the density of states, the above surface doped model shows extreme differences. Specific open-shell features in electronic structure of above surface doped model are illustrated by analysis of partial charge densities of Kohn-Sham orbitals in the band gap energy range. While the surface ingrained dopant readily forms hybrid orbitals with surrounding atoms, the above surface dopant results in orbitals which are much more isolated and little orbital mixing is noted. Molecular dynamics, non adiabatic couplings, and relaxation rates of electrons and holes are also calculated and analyzed.

Cobalt doped TiO<sub>2</sub> anatase (100) surface photoelectrochemical cell: Computational spin restricted analysis of surface ingrained vs. above surface models

248th National Meeting (2014)

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Cobalt doped TiO2 anatase (100) surface photoelectrochemical cell: Computational spin restricted analysis of surface ingrained vs. above surface models

Cobalt doped TiO₂ anatase (100) surface photoelectrochemical cell: Computational spin restricted analysis of surface ingrained vs. above surface models