Imprint effect on energy storage performance of Aurivillius Bi3TaTiO9 thin films

Abstract

We report the imprint effect on the energy storage performance of Bi-layered perovskite (Aurivillius) Bi3TaTiO9 (BTTO) thin films. BTTO thin films were fabricated on single-crystal Nb-doped SrTiO3 substrates using pulsed laser deposition, where the BTTO thin films showed epitaxial c-axis orientation crystal growth with square-shaped grains of terrace structures. The BTTO thin films exhibited ferroelectric hysteresis loops with a remnant polarization of several μC/cm2. An imprint phenomenon in the ferroelectric hysteresis loops occurred by applying the heat treatment of the BTTO thin film. By varying the annealing time (for 5 and 10 min at 550 °C in a vacuum of 10−5 Torr), we elucidated the imprint effect on the energy storage performance. We suggest that oxygen deficiencies induced by the heat treatment cause an imprint effect in the ferroelectric hysteresis loops. As a result, the imprint effect contributed to an increase in the stored energy density and a decrease in the energy loss density in the energy storage performance of the BTTO thin films. Our results demonstrate that the imprint effect can be a critical factor in achieving improved energy efficiency for energy storage performance, which provides new insights into the potential applications of energy storage devices with Bi-layered perovskite BTTO thin films.