Theoretical calculation and experimental study of influence of oxygen vacancy on the electronic structure and hemocompatibility of rutile TiO_2

In this work,the relationship between electronic structure and hemocompatibility of oxygen deficient rutile TiO2-x was studied by both theoretical calculation and experimental study. Based on the local density functional theory,first-principals method was performed to calculate the electronic structure of rutile TiO2 with different oxygen vacancy concentration. In the range of less than 10% of (or equal) physically realistic O vacancy concentration,the band gap of rutile TiO2 increases with increasing O vacancy concentration,leading the TiO2 changes from a p-type to an n-type semiconductor. The valance band of TiO2 is predominated by O 2p orbital,while the conduction band is occupied by Ti 3d orbital for different O vacancy concentration. The O vacancy results in the occupation of electrons at the bottom of conduction band of TiO2,and the donor density increases with increasing O vacancy concentration. When materials come in contact with blood,the n-type semiconductor feature of oxygen deficient TiO2-x with the bottom of conduction band occupied by electrons would prevent charge transfer from fibrinogen into the surface of materials,thus inhibiting the aggregation and activation of platelets,therefore improving the hemocompatibility of rutile TiO2-x.