Configurations, electronic properties, and diffusion of carbon and nitrogen dopants in rutile TiO2: A density functional theory study

Abstract

Doping of TiO${}_{2}$ with nonmetal atoms is known to improve the photoconversion efficiency of the material. Here, we use first-principles calculations to describe the atomic-scale details of migration and configurational changes of typical dopants and oxygen-related native defects in rutile TiO${}_{2}$. The complex pathways for transformations of carbon and nitrogen dopants include structures, which, though very close in energy, have different effects on the electronic properties of the host system in terms of impurity-related gap states. We also find that, because of relatively low diffusion barriers, moderate annealing can activate the migration of impurities and native defects and lead to defect-induced transformations of dopants. Overall, the results are relevant to the dynamics of C and N dopants in rutile TiO${}_{2}$ and to the performance of the material in photocatalytic and photovoltaic applications.