State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, P. R. China.
School of Science, China University of Geosciences , Beijing 100083, P. R. China.
ACS Appl Mater Interfaces. 2016 Feb 10;8(5):3340-8. doi: 10.1021/acsami.5b11231. Epub 2016 Jan 27.
GN/BT nanocomposites were fabricated via colloidal processing methods, and ceramics were sintered through two-step sintering methods. The microstructure and morphology were characterized by X-ray diffraction, high-resolution transmission electron microscopy, and field emission scanning electron microscopy. XRD analysis shows that all samples are perovskite phases, and the lattice parameters a and c almost decrease linearly with the increase of graphene nanosheets. The dielectric properties were tested by using precision impedance. The maximum dielectric constant at the Curie temperature for the nanocomposites with graphene addition of 3 wt % is about 16,000, almost 2 times more than that of pure BaTiO3 ceramics. The relaxation, band structure, density of states, and charge density distribution of GN/BT superlattices were calculated using first-principles calculations for the first time, and results showed the strong hybrid interactions between C 2p states and O 2p and Ti 3d orbitals.
GN/BT 纳米复合材料是通过胶体处理方法制备的，陶瓷是通过两步烧结方法烧结的。采用 X 射线衍射、高分辨率透射电子显微镜和场发射扫描电子显微镜对微观结构和形态进行了表征。XRD 分析表明，所有样品均为钙钛矿相，晶格参数 a 和 c 几乎随石墨烯纳米片的增加呈线性下降。介电性能通过精密阻抗测试。添加 3wt%石墨烯的纳米复合材料在居里温度下的最大介电常数约为 16000，几乎是纯 BaTiO3 陶瓷的 2 倍。首次使用第一性原理计算对 GN/BT 超晶格的弛豫、能带结构、态密度和电荷密度分布进行了计算，结果表明 C 2p 态与 O 2p 和 Ti 3d 轨道之间存在强烈的杂化相互作用。
