氮掺杂对金红石二氧化钛光电特性影响的理论研究

运用第一性原理LDA+U方法，计算不同浓度氮元素掺杂金红石相二氧化钛的能带结构、态密度和光学性质，研究显示氮元素的掺入使TiO_2-x N _x 体系带隙变窄。而O-2p与N-2p轨道杂化耦合在费米能级附近出现了杂质能级，促使载流子跃迁变容易，从而拓展了TiO_2-x N _x 体系对可见光的响应范围。此外，杂质能级对电子-空穴对的复合有抑制作用，对光催化活性的提升具有积极作用。研究结果表明，当氮元素掺杂量（x）为0.062 5时，TiO_2-x N _x 体系光吸收性能与光电响应较好。

Theoretical study on effect of nitrogen doping on photoelectric properties of rutile TiO2

Using first?principles LDA+U method，the band structure，density of states and optical properties of rutile TiO₂ doped with different concentrations of N element were calculated.Investigation indicated that the band gap of TiO_2-x N₂ system was narrowed by the N-dopant.Meanwhile，the impurity level formed by the hybrid coupling of O-2p and N-2p orbitals arised near the Fermi level，it made the carrier transition more readily and extended the response range of TiO_2-x N _x system to visible light.In addition，the impurity level inhibited the recombination of electron?hole pairs and exerted positive effect on the improvement of photocatalytic activity.The research result showed that when N doping amount was 0.062 5，the optical absorption performance and the corresponding photoelectric response of TiO_2-x N _x system were better.