摘要:
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。
Abstract:
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 TiO2, 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.
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