Theoretical calculation and experimental study of influence of oxygen vacancy on the electronic structure and hemocompatibility of rutile TiO2

Abstract

In this work, the relationship between electronic structure and hemocompatibility of oxygen deficient rutile TiO 2− 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 TiO 2 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 TiO 2 increases with increasing O vacancy concentration, leading the TiO 2 changes from a p-type to an n-type semiconductor. The valance band of TiO 2 is predominated by O 2 p orbital, while the conduction band is occupied by Ti 3 d orbital for different O vacancy concentration. The O vacancy results in the occupation of electrons at the bottom of conduction band of TiO 2 , 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 TiO 2− 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 TiO 2- x .