Influence of the Addition of Rare Earth Elements on the Energy Storage and Optical Properties of Bi0.5Na0.5TiO3–0.06BaTiO3 Polycrystalline Thin Films

Abstract

Rare earth element-doped Bi0.5Na0.5TiO3–BaTiO3 (BNT–BT–RE) polycrystalline thin films were processed on a platinized substrate by chemical solution deposition. The microstructure, dielectric, and ferroelectric properties were investigated for all prepared films. It was found that the incorporation of rare earth elements into the BNT–BT matrix increases both the dielectric constant and the breakdown strength while maintaining low dielectric losses, leading to an enhancement of the energy storage density to Wrec = 12 and 16 J/cm3 under an effective field of E = 2500 kV/cm, for Nd- and Dy-based films, respectively. The optical properties of films containing the lanthanide element were investigated and the obtained results bear interest for luminescence applications. The simultaneous appearance of ferroelectric and optical properties in the system under investigation is very promising for advanced optoelectronic devices.

High-Temperature Energy Storage Properties of Bi0.5Na0.5TiO3-0.06BaTiO3 Thin Films

“…In contrast, a clear dielectric loss anomaly was observed around 120 °C at 10 kHz for the film prepared via the CSD method, which corresponds exactly to depolarization temperature localization. As shown in Figure 4b, this anomaly was frequency-dependent and asserted the relaxor behavior of this film [31]. Such an anomaly in…”

“…In contrast, a clear dielectric loss anomaly was observed around 120 • C at 10 kHz for the film prepared via the CSD method, which corresponds exactly to depolarization temperature localization. As shown in Figure 4b, this anomaly was frequency-dependent and asserted the relaxor behavior of this film [31]. Such an anomaly in the dielectric loss was not detected for the film prepared via the PLD method, probably because of the presence of a high leakage current and/or a rather low concentration of polar nanoclusters, which could not give rise to such an anomaly.…”

“…Interestingly, the CSD film showed improved energy storage properties, with a W rec around 1.4 J cm −3 and a high efficiency around 76% at RT, which decreased to 40% at 250 • C. Furthermore, at a temperature ≤ 180 • C the efficiency was still very interesting (η > 70%) and remained relatively stable. The obtained values evidence better performances than some lead-free materials reported to be promising for high-temperature applications [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. It is worth mentioning that in harsh conditions, the ability to rapidly store and release electrical charges could lead to stress corrosion cracking.…”

“…In a recent study, we demonstrated that BNT-0.06BaTiO 3 (BNT-BT)-based thin films exhibited very interesting energy storage properties at room temperature and strong electric fields that exceeded by several orders of magnitude those obtained for solid-state ceramic capacitors [31].…”