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采用密度泛函理论(DFT)平面波赝势方法计算了N/F掺杂和N-F双掺杂锐钛矿相TiO2(101)表面的电子结构.由于DFT方法存在对过渡金属氧化物带隙能的计算结果总是与实际值严重偏离的缺陷,本文也采用DFT+U(Hubbard系数)方法对模型的电子结构进行了计算.DFT的计算结果表明N掺杂后,N2p轨道与O2p和Ti3d价带轨道的混合会导致TiO2带隙能的降低,而F掺杂以及氧空位的引入对材料的电子结构没有明显的影响.DFT+U的计算却给出截然不同的结果,N掺杂并没有导致带隙能的降低,而只是在带隙中引入一个孤立的杂质能级,反而F掺杂以及氧空位的引入带来明显的带隙能降低.DFT+U的计算结果与一些实验测量结果能够较好地符合.
The electron structures of N / F-doped and NF-doubly doped anatase TiO2 (101) surfaces were calculated by density functional theory (DFT) plane-wave pseudopotential method.DFT methods have been used to investigate the effect of DFT on the bandgap energy of transition metal oxides The calculation results always deviate from the actual value. In this paper, the electronic structure of the model is also calculated by the DFT + U (Hubbard coefficient) method. The calculation results of DFT show that the N2p orbital and O2p and Ti3d valence band The mixing of the orbitals leads to the decrease of the bandgap energy of TiO2, while the F doping and the introduction of oxygen vacancies have no obvious effect on the electronic structure of the material. The calculation of DFT + U gives quite different results. N doping does not result in Bandgap energy, but only introduces an isolated impurity level in the bandgap. On the contrary, F doping and the introduction of oxygen vacancies bring about a significant decrease in bandgap energy.The calculation results of DFT + U and some experimental measurements can Better compliance.