Chemical and optical properties of carbon-doped TiO_2: A density-functional study

摘要

The conflict of understandings on experimental results about chemical and optical properties of C-doped TiO_2, which has been overlooked for a long time but is essential for studies of the basic properties of this material, is unraveled. It is shown that in anatase TiO_2 the doped C and O atoms can easily couple with each other at typical synthesis conditions due to the large binding energy and small energy barrier, while in rutile phase, the coupling can hardly occur. The characteristics of the structures are elaborated in detail, which provides insights into the chemical, optical, and magnetic properties of C-doped TiO_2.