Influence of Crystallization Time on Energy-Storage Density and Efficiency of Lead-Free Bi_0.5(Na_0.8K_0.2)_0.5TiO₃ Thin Films

Abstract

Lead-free Bi0.5(Na0.80K0.20)0.5TiO3 (BNKT) ferroelectric films were synthesized on Pt/Ti/SiO2/Si substrates via chemical solution deposition. The influence of crystallization time on the microstructures and ferroelectric and energy-storage properties of the films was investigated in detail. The XRD analysis showed that the BNKT films have well crystallized corresponding to the single-phase perovskite structure at 700°C. Ferroelectric and energy-storage properties of the films were significantly enhanced by increasing crystallization time. With crystallization time of 60 min, the remnant polarization (Pr), maximum polarization (Pm), and Pm-Pr values reached the highest values of 7.9 µC/cm2, 28.9 µC/cm2, and 21.0 µC/cm2, respectively, under the electric field of 400 kV/cm. Thanks to the strong enhancement in Pm and the large Pma-Pr value, the highest recoverable energy-storage density (Jreco) gets the value of 2.9 J/cm3. The obtained results indicate that the BNKT films have application potentials in advanced capacitors.

Effect of Structural Deficiencies on Bi-Ferroic Behaviors of Lead-Free Bi0.5 Na0.40K0.10TiO3 Films

“…Although BNKT materials revealed the multiferroic properties at room temperature, these behaviors are quite poor, and their origin was still unclear. Besides, processing factors, like annealing temperature, annealing time, film thickness are attributed to influence strong to physic properties of BNKT films [28][29][30]. During this work, the physical characteristics of Bi 0 5 Na 0 4 K 0 1 TiO 3 (abbreviated as BNKT) films fabricated by employing a spin coating technique on Pt/Ti/SiO 2 /Si substrates were investigated as a function of annealing time (10,20,40, and 60 min).…”

Influence of Excess Potassium on Structural and Ferroelectric Properties of Lead-Free Bi0.5K0.5TiO3 Thin Films

“…In previous works, the influence of the processing conditions, such as the film thickness, annealing temperature and crystallization time on the electric properties of BKT-based films [18][19][20][21], were investigated. Via modifying A or B-site in the perovskite structure, we have enhanced significantly the electric properties of BKT-based films [22][23][24][25].…”