N/Cu共掺杂锐钛矿型TiO2第一性原理研究

基于密度泛函理论的第一性原理平面波超软赝势法, 采用局域自旋密度近似加Hubbard U值方法研究了纯锐钛矿型TiO₂, N, Cu单掺杂TiO₂及N/Cu共掺杂TiO₂ 的晶体结构、电子结构和光学性质. 研究结果表明, 掺杂后晶格发生相应畸变, 晶格常数变大. N 和Cu的掺杂在TiO₂禁带中引入杂质能级, 禁带宽度发生相应改变. 对于N掺杂TiO₂禁带宽度减小较弱, 而Cu掺杂和N/Cu共掺TiO₂禁带宽度显著降低, 导致吸收光谱明显红移, 光学催化性增强, 有利于实际应用.

First-principles study of N/Cu co-doped anatase TiO2

Using the first-principles plane-wave ultra-soft pseudo-potential method based on the density functional theory, the structures, electronic-structures and optical properties of pure anatase TiO₂, N (Cu) doped TiO_2, and N/Cu co-doped TiO₂ crystal are studied by the local-spin density approximation plus Hubbard U method. It is shown that the lattice constants become larger because of the lattice distortion caused by doping. Impurity levels in the band gap of TiO₂ are introduced by N and Cu doping, and the forbidden band width is correspondingly changed. For N doped TiO₂, the reduction of the band gap is weak, while the N/Cu co-doped TiO₂ band gap decreases remarkably. It leads to a red shift of visible absorption spectrum and enhances optical catalysis. The effect is useful for the practical application of photo-catalytic.