Gholam Turghunjan, Zheng Li Rong, Wang Jia Ou, Qian Hai Jie, Wu Rui, Wang Hui-Qiong
Key Laboratory of Semiconductors and Applications of Fujian Province, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University, Xiamen, 361005, People's Republic of China.
Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
Nanoscale Res Lett. 2019 Apr 18;14(1):137. doi: 10.1186/s11671-019-2965-3.
The Al-doped BiFeO, i.e., BFAO powder samples with x = 0, 0.025, 0.05, and 0.1, were prepared via the hydrothermal route. The effects of Al substitution on the structural, electrical, and optical properties of BFAO samples were investigated. It is found that the substitution of Al ions at B-site of BiFeO did not cause structural change and it still retains the rhombohedral perovskite structure with R3c symmetry, which was confirmed by the X-ray diffraction (XRD) and Raman measurements. X-ray absorption fine structure (XAFS) above the Fe K-edge and Bi L-edge in BFAO powders was also measured and analyzed. Fe ions exhibit mixed valence states (Fe/Fe) while Bi ions keep the + 3 valence state in all the samples. Fe K-edge XAFS also indicated that there was a competition between hybridization of Fe 3d and Al 3d with O 2p orbitals and occurrence of the more 4p orbitals with Al doping. The Bi L-edge XAFS revealed that transition from 2p to 6d state increased, so did the energy of 6d state. Besides, Al ion doping affected both the nearest-neighbor and next-nearest coordination shells of Fe atom and nearest-neighbor shells of Bi atom. Ultraviolet-visible (UV-Vis) spectroscopy results show the BFAO prepared by hydrothermal method could be an appropriate visible-light photocatalytic material.
通过水热法制备了Al掺杂的BiFeO₃，即x = 0、0.025、0.05和0.1的BFAO粉末样品。研究了Al取代对BFAO样品的结构、电学和光学性能的影响。研究发现，在BiFeO₃的B位上取代Al离子不会引起结构变化，它仍然保留具有R3c对称性的菱面体钙钛矿结构，这通过X射线衍射（XRD）和拉曼测量得到证实。还对BFAO粉末中Fe K边和Bi L边以上的X射线吸收精细结构（XAFS）进行了测量和分析。在所有样品中，Fe离子呈现混合价态（Fe²⁺/Fe³⁺），而Bi离子保持+3价态。Fe K边XAFS还表明，Fe 3d与Al 3d和O 2p轨道的杂化之间存在竞争，并且随着Al掺杂，更多的4p轨道出现。Bi L边XAFS显示从2p到6d态的跃迁增加，6d态的能量也增加。此外，Al离子掺杂影响了Fe原子的最近邻和次近邻配位壳层以及Bi原子的最近邻壳层。紫外可见（UV-Vis）光谱结果表明，通过水热法制备的BFAO可能是一种合适的可见光光催化材料。
