Abstract

Defect formation energies, electronic structures and optical properties of non-metal S, lanthanide metal Sc-doped and Sc–S co-doped anatase TiO₂ were systematically investigated via a GGA + U method based on density functional theory (DFT). The on-site Coulomb corrections were applied to both 3d orbitals of Ti atom (U_{Ti_3d}) and 2p orbitals of O atom (U_{O_2p}). The results show all doped TiO₂ systems exhibit a certain degree of red-shift due to the presence of impurity levels in the bandgap; in particular, the S-doped and Sc–S co-doped TiO₂ exhibit better light absorption properties in the visible light range than either pure or Sc-doped TiO₂. In addition, the positive synergistic effect between the Sc and S atoms not only expands the absorption edge, but also increases the light absorption coefficient in the visible region. As a result, the Sc–S co-doped anatase TiO₂ shows the best optical absorption spectrum in all doping systems.

Graphical abstract

中文翻译：

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S掺杂，Sc掺杂和Sc–S共掺杂的锐钛矿型TiO 2的结构，电子和光学性质：DFT + U计算

摘要

通过基于密度泛函理论（DFT）的GGA + U方法，系统地研究了非金属S，镧系金属Sc掺杂和Sc-S共掺杂的锐钛矿型TiO _2的缺陷形成能，电子结构和光学性质。将现场库仑校正应用于Ti原子的3 d轨道（U _{Ti _3 d}）和O原子的2 p轨道（U _{O _2 p}）。结果表明，由于带隙中存在杂质，所有掺杂的TiO ₂系统都表现出一定程度的红移。尤其是掺S和掺Sc的TiO ₂在可见光范围内显示出比纯或Sc掺杂的TiO ₂更好的光吸收性能。另外，Sc和S原子之间的正协同作用不仅扩大了吸收边缘，而且增加了可见光区域的光吸收系数。结果，在所有掺杂系统中，Sc-S共掺杂的锐钛矿型TiO ₂表现出最佳的光吸收光谱。

图形概要