Dielectric Properties of Two-Dimensional Bi₂Se₃ Hexagonal Nanoplates Modified PVDF Nanocomposites

Abstract

Topological insulator two-dimensional (2D) Bi2Se3 hexagonal nanoplates, which are highly insulating in the bulk and have a conductive topological surface state, have been prepared via an “EG- (ethylene glycol-) sol” method and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Bi2Se3/PVDF (polyvinylidene fluoride) nanocomposites with various Bi2Se3 contents have been fabricated by a tape-casting method. The microstructure and dielectric performance of the Bi2Se3/PVDF nanocomposites are studied. The dielectric constant of the dense nanocomposite films keeps a relatively low value of about 16 when the Bi2Se3 content is lower than 12 vol.% then suddenly increases to 36 with a critical Bi2Se3 content of 13 vol.% due to the percolation effect of the large aspect ratio of the 2D Bi2Se3 nanoplates. The study of the Bi2Se3/PVDF nanocomposite system is conducive to the exploration of high-performance dielectrics.

Single-particle properties of topological Wannier excitons in bismuth chalcogenide nanosheets

“…The explicit forms of these potentials in momentum space read where is a screening length that depends on the dielectric constants of Bi 2 Se 3 and the surrounding environment. We have chosen the relative permittivity , which is a typical low value for the environment 71 . The bulk dielectric constant has been set to in accord with recent first-principles studies of rhombohedral Bi 2 Se 3 in the near-infrared region at 6 QLs 72 , 73 .…”