High Energy Efficiency and Thermal Stability of BaTiO₃–BiScO₃ Thin Films Based on Defects Engineering

Abstract

ABO3 perovskite ferroelectric thin films have gained wide attention in recent years for high density capacitive energy storage applications. In this regard, BaTiO3–BiMeO3, where Me is a metal cation, are particularly promising materials because of their high electrical polarization and low hysteresis losses. However, for a broader adoption of BaTiO3–BiMeO3 thin films in advanced electronics applications, it is necessary to maintain good thermal stability in addition to high energy density and energy storage efficiency. In this work, we show that a superior combination of these characteristics can be obtained through the control of different defect concentrations, viz., A-site cation vacancies (VA) and B-site ionic substitutions (MeTi). It is shown for BaTiO3–BiScO3 thin films that an optimum combination of VA and ScTi leads to a high energy storage density of 40.5 J cm–3 and an efficiency higher than 85%, which could be maintained from room temperature to 200 °C. A mechanistic understanding of the enhanced energy storage performance based on the synergistic effect of random fields introduced by A-site vacancies and strong hole trapping by ScTi acceptor centers is proposed. Perovskite ferroelectric thin films capable of maintaining high performance at high temperatures may facilitate the advancement of power electronics applications in harsh environments.

Critical Effect of Film–Electrode Interface on Enhanced Energy Storage Performance of BaTiO3–BiScO3 Ferroelectric Thin Films

“…As shown earlier in refs , , the leakage current and breakdown voltages measured at room temperature for the films BSBT 510 °C and BSBT 550 °C are similar, and therefore these factors are not the main determining criteria for the marked improvement in the energy storage properties. Instead, the increase in the energy storage performance of the BSBT films with an increase in T d can be attributed to the following two factors.…”

“…Details of fabrication of BSBT thin films can be found in previous reports. , Briefly, the films of composition 0.1BiScO 3 –0.9BaTiO 3 were deposited at two different temperatures (510 and 550 °C) in 90%O 2 + 10%O 3 at a pressure of 250 mTorr using the pulsed laser deposition technique. The distance between the substrates and target was kept at 6 cm for all samples.…”

“…Ferroelectric thin films have been studied extensively for a wide variety of devices, such as memories, sensors, and actuators. − These devices are typically fabricated in the form of a film/electrode/substrate heterostructure, where the interface quality plays a crucial role in the device performance . One of the important applications of ferroelectric thin films is as capacitor-related components in electronic integrated circuits and other energy storage applications. , For fabrication of thin-film capacitors, different materials are used as conductive bottom electrodes. − Among them, platinum (Pt) is widely used due to its chemical inertness, which makes it highly conductive even at very high operating temperatures. − Nevertheless, several complications related to a film–electrode interface can limit the practical use of Pt. For example, hillock formation within the Pt-bottom electrode layer can degrade the quality of the film–electrode interface, even leading to short-circuiting the capacitor structure. , Second, deterioration in the electrical properties of ferroelectric films on the Pt-bottom electrode has also been reported due to the formation of an interfacial amorphous layer .…”

“…Solid solutions of BaTiO 3 –BiMeO 3 (where Me is a metal) have emerged as an important class of Pb-free ferroelectric materials, especially for high-temperature capacitor applications . In this regard, we previously reported that the energy storage properties of BaTiO 3 –BiScO 3 (BSBT) thin films can be greatly enhanced through the control of crystallographic texture and defect chemistry. , Nevertheless, the effect of the film–electrode interface, specifically with regard to the interface chemistry and structure, on the energy storage performance of BSBT/Pt heterostructures is not well understood. To gain an understanding in this important area, we performed a systematic study of the local chemistry and structure at the interface between BSBT thin films and Pt-bottom electrodes.…”

Structural Changes from Conventional SrSnO3 to Ruddlesden–Popper Sr2SnO4 Perovskites and Its Implication on Photoluminescence and Optoelectronic Properties

“…Structure–property correlation is one of the most fundamental aspects of material design that needs understanding at the molecular level for achieving excellence for designated applications. − Structure is a multivariate parlance, and it broadly covers several materials’ parameters such as defects, symmetry, distortions, and so forth. ,− Among multifunctional ceramics, the ABX 3 type perovskite is in the realm of scientific investigations owing to its interesting and unique optical, magnetic, catalytic, electrical, electronic, and dielectrics properties. − ,,,− SrSnO 3 in particular has been one of the most explored perovskites in achieving excellence in the area of luminescence, optoelectronics, ferroelectricity, and photocatalysis. − …”