Since the positive influences of defects on the performance
of
electroceramics were discovered, investigations concerning on defects
and aliovalent doping routes have grown rapidly in the fields of inorganic
chemistry and condensed matter physics. In this article, we summarized
the types of defects in electroceramics as well as characterization
tools of defects and highlighted the effects of intrinsic and extrinsic
defects on the material performances with the emphasis on dielectric,
ferroelectric, and piezoelectric properties. We mainly introduced
defect related theoretical simulation and experimental results in
several typical incipient ferroelectrics, ferroelectrics, and antiferroelectrics.
Hence, the influences of defects on the crystal lattice were summed
up, and then the main physical mechanisms were highlighted. Particularly,
the performance enhancements of aliovalently doped electroceramics
were also evaluated and reviewed. Finally, the outlook and challenges
were discussed on the basis of their current developments. This article
covers not only an overview of the state-of-the-art advances of defects
and aliovalent doping routes in electroceramics but also the future
prospects that may open another window to tune the electrical performance
of electroceramics via intentionally introducing certain defects.
In this study, the excellent energy storage performance is achieved by constructing opposite double-heterojunction ferroelectricity-insulator-ferroelectricity configuration. The PbZr 0.52 Ti 0.48 O 3 films and Al 2 O 3 films are chosen as the ferroelectricity and insulator, respectively. The microstructures, polarization behaviors, breakdown strength, leakage current density, and energy storage performance are investigated systematically of the constructed PbZr 0.52 Ti 0.48 O 3 /Al 2 O 3 /PbZr 0.52 Ti 0.48 O 3 opposite double-heterojunction. The ultrahigh electric field breakdown strength (≈5711 kV cm −1 ) is obtained, which is beneficial to achieve high energy storage density. Meanwhile, the high linearity of hysteresis loops with low energy dissipation is obtained at a proper annealing temperature, which is induced by partially crystallized and is in favor of achieving high energy storage efficiency η. The PbZr 0.52 Ti 0.48 O 3 / Al 2 O 3 /PbZr 0.52 Ti 0.48 O 3 annealed at 550 °C exhibits excellent energy storage performance with a storage density of 63.7 J cm −3 and efficiency of 81.3%, which is ascribed to the synergetic effect of electric breakdown strength (E BDS = 5711 kV cm −1 ) and the polarization (P m -P r = 23.74 µC cm −2 ). The proposed method in this study opens a new door to improve the energy storage performance of inorganic ferroelectric capacitors. Keywords breakdown strength, energy storage, heterojunctions, polarization behavior
This study examined the effect of the amino acid composition of protein capsids on virus inactivation using ultraviolet (UV) irradiation and titanium dioxide photocatalysis, and physical removal via enhanced coagulation using ferric chloride. Although genomic damage is likely more extensive than protein damage for viruses treated using UV, proteins are still substantially degraded. All amino acids demonstrated significant correlations with UV susceptibility. The hydroxyl radicals produced during photocatalysis are considered nonspecific, but they likely cause greater overall damage to virus capsid proteins relative to the genome. Oxidizing chemicals, including hydroxyl radicals, preferentially degrade amino acids over nucleotides, and the amino acid tyrosine appears to strongly influence virus inactivation. Capsid composition did not correlate strongly to virus removal during physicochemical treatment, nor did virus size. Isoelectric point may play a role in virus removal, but additional factors are likely to contribute.
In this letter, we propose an effective route to obtain large recoverable strain, purely electrostrictive effects and high energy-storage density by inducing defect dipoles into Na0.5Bi0.5TiO3 (NBT)-based relaxor ferroelectrics. It has been found that pinched and double polarization hysteresis loops with high maximum polarization (Pmax) and negligible remanent polarization (Pr) can be observed due to the presence of acceptor-induced defect dipoles. A large recoverable strain of 0.24% with very little hysteresis and high electrostriction coefficient of 0.022 m4 C2 with purely electrostrictive characteristics were acquired when 11 mol. ‰ Mn-doped. Meanwhile, a high recoverable energy density of 1.06 J/cm3 with excellent temperature stability was obtained at the same composition owing to the enlarged value of Pmax-Pr (36.8 μC/cm2) and relatively high electric field (95 kV/cm). Our achievement can open up the exciting opportunities for ferroelectric materials in high-precision positioning devices and high electric power pulse energy storage applications.
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