Yang Fan, Yang Liang, Ai Changzhi, Xie Pengcheng, Lin Shiwei, Wang Cai-Zhuang, Lu Xihong
State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, China.
College of Materials and Chemical Engineering, Hainan University, Haikou 570228, China.
Nanomaterials (Basel). 2018 Jun 21;8(7):455. doi: 10.3390/nano8070455.
The physical and chemical properties of V-M″ and Nb-M″ (M″ is 3d or 4d transition metal) co-doped BaTiO₃ were studied by first-principles calculation based on density functional theory. Our calculation results show that V-M″ co-doping is more favorable than Nb-M″ co-doping in terms of narrowing the bandgap and increasing the visible-light absorption. In pure BaTiO₃, the bandgap depends on the energy levels of the Ti 3d and O 2p states. The appropriate co-doping can effectively manipulate the bandgap by introducing new energy levels interacting with those of the pure BaTiO₃. The optimal co-doping effect comes from the V-Cr co-doping system, which not only has smaller impurity formation energy, but also significantly reduces the bandgap. Detailed analysis of the density of states, band structure, and charge-density distribution in the doping systems demonstrates the synergistic effect induced by the V and Cr co-doping. The results can provide not only useful insights into the understanding of the bandgap engineering by element doping, but also beneficial guidance to the experimental study of BaTiO₃ for visible-light photoelectrical applications.
基于密度泛函理论，通过第一性原理计算研究了V-M″和Nb-M″（M″为3d或4d过渡金属）共掺杂BaTiO₃的物理和化学性质。我们的计算结果表明，在缩小带隙和增加可见光吸收方面，V-M″共掺杂比Nb-M″共掺杂更有利。在纯BaTiO₃中，带隙取决于Ti 3d和O 2p态的能级。适当的共掺杂可以通过引入与纯BaTiO₃的能级相互作用的新能级来有效地调控带隙。最佳的共掺杂效果来自V-Cr共掺杂体系，该体系不仅具有较小的杂质形成能，而且显著降低了带隙。对掺杂体系的态密度、能带结构和电荷密度分布的详细分析表明了V和Cr共掺杂引起的协同效应。这些结果不仅可以为理解元素掺杂的带隙工程提供有用的见解，而且可以为BaTiO₃用于可见光光电应用的实验研究提供有益的指导。
