Anisotropic electrical properties of semiconductive Bi2S3 nanorod filled ferroelectric polyvinylidene fluoride

A novel ferroelectric polymer composite with semiconductive Bi2S3 nanorods loaded in ferroelectric polyvinylidene fluoride (PVDF) is prepared via a simple solution-cast method. A high dielectric constant of over 100, which is over 10 times larger than that of the polymer matrix, is obtained in the percolative composite with a low loading concentration of 0.5 vol% Bi2S3 nanorods. The preferential orientations of Bi2S3 nanorods in the polymer PVDF lead to anisotropy of electrical properties of the composite along the directions parallel (in-plane) and perpendicular (out-of-plane) to the sample surface. The in-plane dielectric constant of the percolative composite sharply decreases at low frequency, and this anisotropy becomes small at high frequency.