Density Functional Characterization of the Visible-Light Absorption in Substitutional C-Anion- and C-Cation-Doped TiO2
Density Functional Characterization of the Visible-Light Absorption in Substitutional C-Anion- and C-Cation-Doped TiO2
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DOI：
10.1021/jp808483a
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发表时间：
2009-01
影响因子：
3.7
通讯作者：
Kesong Yang;Ying Dai;Baibiao Huang;M. Whangbo
中科院分区：
文献类型：
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作者：
Kesong Yang;Ying Dai;Baibiao Huang;M. Whangbo
通过第一性原理密度泛函理论计算，研究了锐钛矿和金红石型TiO₂两种可能的碳替代掺杂结构（即氧位碳掺杂（C@O）和钛位碳掺杂（C@Ti）的TiO₂）的结构和电子性质。在C@O的碳掺杂TiO₂中，带隙略有变化，但掺杂的碳引入了具有C 2p轨道特征的自旋极化带隙态。因此，价带、导带和带隙态之间相关的电子激发解释了碳阴离子掺杂TiO₂所观察到的各种可见光吸收阈值。对于C@Ti的碳掺杂锐钛矿和金红石型TiO₂，掺杂的C原子不会诱导自旋极化态。对于C@Ti的碳掺杂锐钛矿TiO₂，光吸收能降低了约0.18 eV，并且C掺杂剂形成了一个类似二氧化碳的具有短C - O键距的线性O - C - O单元，这与实验结果一致。在C@Ti的碳掺杂金红石型TiO₂中，碳掺杂使光吸收能降低了约0...
The structural and electronic properties of two possible substitutional carbon-doped structures of anatase and rutile TiO2 [i.e., C for O (C@O)- and C for Ti (C@Ti)-doped TiO2] were studied by performing first-principle density functional theory calculations. In C-doped TiO2 with C@O, the band gap changes slightly, but the doped carbon introduces spin-polarized gap states of C 2p orbital in character. Thus, the associated electron excitations among the valence band, the conduction band, and the gap states explain the various visible-light absorption thresholds observed for C anion-doped TiO2. For C-doped anatase and rutile TiO2 with C@Ti, the doped C atom does not induce spin-polarized states. For C-doped anatase TiO2 with C@Ti, the optical absorption energy is reduced by about 0.18 eV, and the C dopant forms a linear O−C−O unit with short C−O distance resembling carbon dioxide, which is consistent with experiment. In C-doped rutile TiO2 with C@Ti, C-doping reduces the optical absorption energy by about 0...