双氮协同钴掺杂锐钛矿相二氧化钛电子结构的第一性原理研究
Tailoring the electronic structure of anatase TiO2 by double N with Co codoping from density function theory calculations

采用基于密度泛函理论的第一性原理计算了双氮原子协同钴原子共掺杂TiO2的几何结构和电子结构. 计算结果发现: 双氮原子掺杂引起的双空穴位与钴原子形成了较强的耦合作用, 并引起晶格结构发生明显变化. 共掺杂的协同效应引起TiO2禁带宽度变窄，在价带顶和导带底出现大量杂质能级, 从而引起吸收带边发生明显红移. 该掺杂方式对调制TiO2禁带宽度有明显的效果, 有望指导后续的实验合成.
Using density function theory calculations, a double-mediated coupling of dopant by two N and one Co atoms is confirmed in TiO2. The doped geometries and electronic structures are calculated. Substituting the two neighboring oxygen atoms by N atoms and the Ti by Co atom, the results show that net two holes couple strongly with the Co atom and a significant lattice relaxation occurs. The codoping synergistic effect results in an obvious band gap narrowing with some impurity bands laying above valance band and some below conduction band, which leads the absorption edge shift to visible region substantially. We expect this generic band-structure tailoring scheme will be applied to other photocatalytic systems and beyond.