STRUCTURAL, FERROELECTRIC AND ENERGY-STORAGE PROPERTIES OF LEAD-FREE Zr-DOPED Bi0.5(Na0.80K0.20)0.5TiO3 FILMS

Abstract

Perovskite-type lead-free Bi[Formula: see text](Na[Formula: see text]K[Formula: see text](Ti[Formula: see text]Zrx)O3 (BNKT-[Formula: see text]Zr) ferroelectric films (with [Formula: see text] from 0.00 to 0.05) were synthesized on Pt/Ti/SiO2/Si substrates via chemical solution deposition. The influence of Zr[Formula: see text] concentration on the microstructures, ferroelectric and energy-storage properties of the prepared films was investigated in detail. It showed that the BNKT-[Formula: see text]Zr films possessed rhombohedral and tetragonal symmetries in morphotropic phase boundary when a small amount of Zr[Formula: see text] was added. Ferroelectric and energy-storage properties of the films investigated at an applied electric field of 600[Formula: see text]kV/cm were significantly enhanced with appropriate Zr[Formula: see text] concentration. The remnant polarization ([Formula: see text]), maximum polarization ([Formula: see text]) and [Formula: see text]–[Formula: see text] values at [Formula: see text] reached the highest values of 18.1[Formula: see text][Formula: see text]C/cm2, 42.0[Formula: see text][Formula: see text]C/cm2 and 24.0[Formula: see text][Formula: see text]C/cm2, respectively. Thanks to the strong enhancement in [Formula: see text] and the large [Formula: see text]–[Formula: see text] value, the highest recoverable energy-storage density gets the value of 4.6[Formula: see text]J/cm3 for the 2[Formula: see text]mol.% Zr[Formula: see text]-doped BNKT film. These obtained results indicate that the appropriate Zr[Formula: see text]-doped BNKT films have many application potentials in the advanced capacitors.