Structural and electronic properties of TiO2 from first principles calculations

In this chapter, we address the computational description of structural and electronic properties of TiO2. Particular emphasis is given to the key methodological aspects related to density functional theory calculations on titania. In particular, it is necessary to correctly account for the self-interaction error in the adopted functional in order to prevent problems such as the severe underestimation of the TiO2 bandgap and the strong bias toward the full delocalization of excess electrons and holes, leading eventually to calculated results in contrast with the experimental evidence. We hereby review computational results on pristine and reduced titania, discussing the nature and the main features of the intrinsic defects (oxygen vacancies and interstitial Ti). We provide insights on the trapping of photoexcited charge carriers and their separation in TiO2 nanocomposites. The last section concerns the modeling of large and complex titania nanoparticles.