title: Dielectric Enhancement in Graphene/Barium Titanate Nanocomposites.
abstract: 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.
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, P. R. China.
authors.forename: Bingcheng
authors.initials: B
authors.lastname: Luo
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, P. R. China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Science, China University of Geosciences , Beijing 100083, P. R. China.
authors.forename: Enke
authors.initials: E
authors.lastname: Tian
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, P. R. China.
authors.forename: Huiling
authors.initials: H
authors.lastname: Gong
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, P. R. China.
authors.forename: Qiancheng
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, P. R. China.
authors.forename: Zhengbo
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Nanjing SCF Nanotech Ltd. , Nanjing 211800, P. R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Nanjing SCF Nanotech Ltd. , Nanjing 211800, P. R. China.
authors.forename: Xiaoyue
authors.initials: X
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University , Beijing 100084, P. R. China.
authors.forename: Longtu
authors.initials: L
authors.lastname: Li
keywords: BaTiO3; dielectric; ferroelectric; first-principles; graphene