Energy Storage and Leakage Current Characteristics of Low-Temperature-Derived Pb_0.8La_0.1Ca_0.1Ti_0.975O₃ Thin Films Tailored by an Annealing Atmosphere

Abstract

Sol−gel-derived (100)-textured Pb 0.8 La 0.1 Ca 0.1 Ti 0.975 O 3 (PLCT) thin films were prepared on Pt/Ti/SiO 2 /Si(100) substrates at a low temperature of 450 °C. Modification of annealing atmospheres, i.e., O 2 , air, and N 2 , on the electrical properties of PLCT thin films was focused on in this work, especially the energy storage and leakage current characteristics. In contrast to some secondary phases, such as PbO x and pyrochlore phase, detected in the PLCT films annealed in air and N 2 , a phase-pure PLCT thin film was achieved when subjected to O 2 annealing. In addition, a significant influence of the annealing atmosphere on the leakage current characteristics of PLCT films was revealed and the distinct current density−electric field (J−E) behaviors were fitted to three charge transport models: Ohmic conduction, modified Schottky emission, and Fowler−Nordheim tunneling. Importantly, unlike the PLCT thin films annealed in air and N 2 that exhibited poor P−E hysteresis loops, a slim, tilted P−E loop with a P max of 94.5 μC/cm 2 and a P r of 11.5 μC/cm 2 was obtained in the PLCT thin film annealed in O 2 . This feature endows it excellent energy storage capacity with a high recoverable energy density (W re ∼ 21.9 J/cm 3 ) and efficiency of η ∼ 65.6%, showing great potential in high-performance dielectric capacitors.

Domain-Enhanced Energy Storage, Piezoelectric, and Dielectric Properties in Pb(Zr0.52Ti0.48)O3/SrTiO3 Ferroelectric Superlattices

“…High energy storage density depends on low P r and narrow P–E loops. Generally, the value of energy storage density can be calculated from P–E loops with the following equation. , W normalr normale normalc = prefix∫ P normalr P normalm E normald P where W rec is energy storage density, and E is the electric field of dielectric materials. Figure b shows the W rec and efficiency (η) of the PZT/STO superlattices and PZT films at different electric fields.…”

“…Generally, the value of energy storage density can be calculated from P−E loops with the following equation. 25,26 = W E P d…”

Effect of annealing temperature on energy storage performance of Ba(Zr0.35Ti0.65)O3 thin films under pure oxygen

“…Oxygen vacancies in ferroelectric films can generate conductive electrons according to the following equation: 15,26…”

“…Oxygen vacancies in ferroelectric films can generate conductive electrons according to the following equation: 15,26 which can cause a sharp increase in film leakage current. Annealing in an oxygen-rich atmosphere can move the above equation that generates oxygen vacancies in the opposite direction, compensating for the generation of oxygen vacancies.…”

Synergically improved energy storage performance and stability in sol–gel processed BaTiO 3/(Pb,La,Ca)TiO 3/BaTiO 3 tri-layer films with a crystalline engineered sandwich structure

“…According to the above discussion, a ferroelectric film with superior energy storage capacity should feature a tilted and elongated P-E loop, i.e., a large maximum polarization (P m ) while a small remnant one (P r ) and a high breakdown strength (E b ). To this day, many strategies involving the material engineering from the nanoscale up have been used to modify P-E characteristics of a ferroelectric film for capacitive energy storage, including chemical modification with specific dopants/defects [1,[9][10][11][12][13][14], polymorphic domain/ morphotropic phase boundary (MPB) regulation [1,[15][16][17][18][19][20][21], compositing with a nanoscale-dispersed second phase [22][23][24], engineering a fine-grain structure [25][26][27], construction of multilayers/superlattices based on interface & strain effects [28][29][30][31][32][33][34][35][36]. Under these efforts (to produce higher polarization, higher applicable electric field, lower loss, or combination of them), the recoverable energy density (W rec ) of ferroelectric films have been rapidly increased to a level of 10-100 J/cm 3 , a boost of 1-2 orders of magnitude as compared with those of their bulk counterparts.…”