N掺杂和N-V共掺杂锐钛矿相TiO_2的第一性原理研究  

First-principles study of N-doped and N-V co-doped anatase TiO_2

作　　者：徐金荣[1] 王影[1] 朱兴凤[2] 李平[1] 张莉[1] 

机构地区：[1]安徽建筑工业学院数理系,合肥230601 [2]南京师范大学物理科学与技术学院,南京210097

出　　处：《物理学报》2012年第20期410-415,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11104001);安徽省优秀青年人才基金(批准号:2012SQRL135);安徽建筑工业学院青年科研号项项目(批准号:201 183-18)资助的课题~~

摘　　要：采用基于密度泛函理论的投影缀加平面波方法和广义梯度近似加Hubbard参数的似近,研究了锐钛矿相TiO_2,N掺杂TiO_2和N-V共掺杂TiO_2体系的基态原子构型、电子结构.结果表明,N掺杂后,其晶胞体积比末掺杂时要略微增大,基态构型并未发生明显变化,而N-V共掺杂时,对称性被破坏,V原子向N原子附近靠近.计算得到的锐钛矿相TiO_2带隙E_(gap)为3.256 eV,与实验值3.23 eV非常接近.N掺杂TiO_2带隙降低了0.4 eV,而N-V共掺杂带隙降低至2.555 eV.此外,N-V共掺杂会在价带顶和导带底之间形成受主和施主能级,这种能级对光生电子-空穴对的分离是非常有利的,降低了再次复合的概率.因此,N-V共掺杂TiO_2可以有效地提升TiO_2作为光催化剂的催化能力.The ground state atomic configurations and electronic structures of anatase TiO2, N-doped TiO2 and N-V co-doped TiO2 are studied by the projector augmented wave method and the generalized gradient approximation plus U （Hubbard correction） （GGA＋U） based on the density functional theory. The results indicate that the volume of cell is slightly larger and the ground state configuration has no change significantly for N-doped TiO2, but the symmetry of cell is broken and the position of V atom is more close to N atom after co-doping with N and V. The band gap of anatase TiO2 is calculated to be 3.256 eV, which is in agreement with experimental value （3.23 eV）. When N is doped, the gap is reduced by more than 0.4 eV. but for N-V co-doped system, the gap reduces to 2.555 eV. Moreover, the acceptor level and donor level, which can be formed between the valence band maximum and the conduction band minimum because of co-doping with N and V, are more favorable to the separation of photoelectron-hole pairs and reduce the rate of recombination. Therefore, the co-doping of anatase TiO2 with N and V can effectively improve the photocatalytic performance of anatase.

关 键 词：密度泛函 广义梯度近似加Hubbard参数似近 掺杂 电子结构 

分 类 号：O469[理学—凝聚态物理]