S与V掺杂锐钛矿相TiO2电子结构和光学性质的第一性原理研究

First-principles Study on Electronic Structure and Optical Property of S and V Doped Anatase TiO2

采用基于密度泛函理论(DFT)的第一性原理平面波超软赝势方法研究了S与V单掺杂及共掺杂锐钛矿相TiO2的电子结构和光学性质.结果表明:单掺杂和共掺杂均使禁带宽度减小,且位于价带和导带之间的杂质能级能够捕获由价带跃迁至导带的电子,减少光生载流子的复合率;在光学性质中,单掺体系和共掺体系的光吸收带边均发生了红移,在可见光区的吸收系数增加,整体有效提高了TiO2的光催化效率.

The electronic structures of S-doped,V-doped and S-V co-doped anatase TiO2 were investigated by the firstprinciples plane wave ultra-soft pseudo-potential method based on the density functional theory(DFT).The crystal structures and optical properties were analyzed.The results indicate that the band gap of single doped samples is narrowed as the same as the S-V co-doped TiO2.Also the impurity energy levels appear near the Fermi level,which can reduce the recombination rates of photoexcited carriers.From the calculation of the optical properties,it is known that two kinds of doped systems all lead to the red shift of the optical absorption edges,the absorption coefficient increases in visible-light region,which demonstrates that the photocatalytic property is greatly improved.