Enhanced dielectric and electrical properties of tri-phase percolative PVDF–BiFeO₃–Carbon Black (CB) composite film

A tri-phase polymer composite film with a multiferroic phase (BiFeO₃) and conductive carbon black (CB) deposited on the BiFeO₃ (BF) and poly(vinylidene fluoride) (PVDF) matrix were prepared by using a solution casting technique. The dielectric and electrical performance of BF–PVDF composites with various weight percentages of CB content was studied. It has been observed that the incorporation of high loading of CB to the BF–PVDF composite system led to a significant improvement in the dielectric constant with suppressed dielectric loss (< 0.5). The high dielectric constant of 69 at 100 Hz, which is 11 times greater than that of neat PVDF film with a lower dielectric loss of 0.41, is obtained for PVDF–BF–CB composites as CB content (8 wt%) approached the percolation threshold. Furthermore, the improvement of dielectric and electrical performance of the PVDF–BF–CB composites may be due to the synergistic effect of the multiferroic phase BF and conductive phase CB as a result of homogeneous dispersion within the polymer matrix. These high dielectric constant and suppressed dielectric loss PVDF–BF–CB composites might be suitable for potential applications in the field of future thin-film capacitors.