Cu-doped KTa0.6Nb0.4O3 nanoparticles for enhancing the dielectric properties of PVDF composite film

Electronic devices frequently make use of dielectric materials, which are also essential to the development of advanced electronics, medical technology, and avionics. Here, a new strategy of doping KTa0.6Nb0.4O3 (KTN) with different copper ion contents was prepared by hydrothermal synthesis. The dielectric constant of PVDF-KTN-4%Cu (1 kHz, ε′ = 44.15) composite film prepared by organic–inorganic composite is higher than those of PVDF-KTN-1%Cu (1 kHz, ε′ = 40.66), PVDF-KTN (1 kHz, ε′ = 37.53), and pure PVDF film (1 kHz, ε′ = 6.79). Results also show that the loss angle and electrical modulus of the PVDF-KTN-Cu composite films are smaller than those of PVDF-KTN. The lattice distortion of octahedra was calculated by first-nature principle to derive the most likely K sites for copper-ion substitution. The distortion parameter and the dielectric constant increased along with the copper-ion content, which enhanced local polarization. This method offers a fresh way to create composites with superior dielectric properties.