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The electronic structure and optical properties of K2Ti6O13 doped with transition metals
LuHong Yan
Author NameAffiliationE-mail
LuHong Yan Huaibei Normal University luhongyan2006@gmail.com 
Abstract:
Based on the experimental study of the optical properties of K2Ti6O13 doped with Fe and Ag, some properties of them including the electronic structure and the optical properties are studied by the first-principles plane-wave ultra-soft pseudo-potential method based on the density functional theory (DFT). The calculated optical properties are consistent with the experiment results. After doping, the absorption edges of K2Ti6O13 extend to the visible-light region. The enhanced absorption of visible light is believed to be due to that K2Ti6O13 doped with substitutional Fe and Ag have isolated impurity bands mainly hybridized by Fe 3d states or Ag 4d states with Ti 3d states and O 2p states and the band gaps become narrower. For Fe-doped K2Ti6O13, these impurity bands are in the middle of the band gap, thus these impurity bands can be used as a bridge for valence band electrons transition to the conduction band. For Ag-doped K2Ti6O13, the impurity bands form a shallow acceptor above the valence band and can reduce the recombination rate of photoexcited carriers. The experimental and calculated conclusions have meaningful implications for the development and understanding of K2Ti6O13 that have absorption under visible light.
Key words:  First-principle calculation  The impurity bands  The visible-light region  Narrower
FundProject:
过渡金属掺杂K2Ti6O13的电子结构和光学性质
路洪艳
摘要:
在对Fe和Ag掺杂后K2Ti6O13光学性质实验研究的基础上,本文利用基于密度泛函理论(DFT)下的第一性原理平面波超软赝势法研究了它们的电子结构和光学性质。光学性质的计算结果和实验相符。计算表明,Fe和Ag掺杂后,K2Ti6O13的带隙中出现了杂质带且其带隙值变小,因而使掺杂后的K2Ti6O13的吸收边延伸到可见光区,即实现了对可见光吸收。其中杂质带主要由Fe 3d态或Ag 4d态与Ti 3d态和O 2p态杂化而成。对于Fe掺杂的K2Ti6O13,这些杂质带位于带隙的中间,因此可以作为电子从价带跃迁到导带的桥梁。对于Ag掺杂的K2Ti6O13,杂质带位于价带顶附近为受主能级,可以降低光生载流子的复合概率。实验和计算研究表明,通过Fe和Ag的掺杂实现了K2Ti6O13对可见光的吸收,这对进一步研究K2Ti6O13的光学性质具有重要的意义
关键词:  第一性原理计算  杂质带  可见光区  变窄
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