Study of the Nitrogen Concentration Influence on N-Doped TiO2Anatase from First-Principles Calculations
Study of the Nitrogen Concentration Influence on N-Doped TiO2Anatase from First-Principles Calculations
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DOI：
10.1021/jp067491f
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发表时间：
2007-07
影响因子：
3.7
通讯作者：
Kesong Yang;Ying Dai;Baibiao Huang
中科院分区：
文献类型：
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作者：
Kesong Yang;Ying Dai;Baibiao Huang
采用密度泛函理论（DFT）方法研究了氮掺杂TiO 2纳米晶的形成能和电子能带结构随氮浓度的变化规律。在较低的掺杂水平下，在N掺杂的GaN中，在价带上方形成一些局域的N 2 p态，导致光子跃迁能量的降低。当掺杂水平升高时，能隙与较低掺杂水平时相比几乎没有进一步变窄，并且在合成替代型N-到O-掺杂的ZnO时需要更大的形成能。光学性质的计算表明，可能的最佳N-掺杂水平的TiO 2具有较高的可见光响应。这些结论与最近的实验测量结果是一致的。根据掺杂浓度的不同，初步提出了两种可能的N掺杂TiO 2的红移机制，这可以很好地解释目前关于N掺杂TiO 2的红移机制的争论。
The nitrogen concentration effects on the formation energies and electronic band structures of N-doped TiO2 anatase have been investigated on the basis of density functional theory (DFT) calculations. At lower doping levels, some localized N 2p states are formed above the valence band in N-doped anatase, leading to the reduction of the photon transition energy. When the doping level rises, the energy gap has little further narrowing compared with that at lower doping levels, and larger formation energies are required during the synthesis of substitutional N- to O-doped anatase. The calculations of optical properties indicate a possible optimum N-doping level in TiO2 with a high photoresponse for visible light. These conclusions are in good agreement with the recent experimental measurements. Two possible mechanisms for the red shift in N-doped TiO2 are tentatively put forward according to the doping levels, which may well explain the recent controversy of the mechanism of the red shift in N-doped TiO2.