Density functional characterization of the electronic structure and visible-light absorption of Cr-doped anatase TiO(2).
Density functional characterization of the electronic structure and visible-light absorption of Cr-doped anatase TiO(2).
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DOI：
10.1002/cphc.200900188
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发表时间：
2009-09
期刊：
影响因子：
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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
为了评价Cr掺杂TiO（2）的电子和光学性质，采用第一性原理密度泛函理论计算方法研究了Cr掺杂TiO（2）的三种可能模型：Cr在Ti位（模型I）、Cr在Ti位并有氧空位补偿（模型II）和Cr间隙位（模型III）.在模型I中，用GGA+U方法成功地描述了Cr 3d态的分裂行为和绝缘性质，由此提出Ti位上的Cr应该以Cr（4+）的形式存在，而不是通常认为的Cr（3+）。因此，这些杂质状态之间的电子跃迁，导带（CB），和价带（VB），以及占据和未占据的Cr 3d状态之间的d-d跃迁，提供了一个合理的解释实验观察到的主要和次要的吸收带。在模型II和III中，杂质状态和相关的光学跃迁过程，以及相应的电子构型进行检查。
To evaluate the electronic and optical properties of Cr-doped anatase TiO(2), three possible Cr-doped TiO(2) models, including Cr at a Ti site (model I), Cr at a Ti site with an oxygen vacancy compensation (model II), and an interstitial Cr site (model III), are studied by means of first principles density functional theory calculations. In model I, the splitting behavior of the Cr 3d states and the insulating properties are successfully depicted by the GGA+U method, from which it is proposed that Cr at a Ti site should exist as Cr(4+) instead of the generally believed Cr(3+). As a result, the electron transitions between these impurity states, the conduction band (CB), and the valence band (VB), as well as the d-d transitions between occupied and unoccupied Cr 3d states, provide a reasonable explanation for the experimentally observed major and minor absorption bands. In models II and III, the impurity states and associated optical transition processes-as well as the corresponding electron configurations-are examined.