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The morphology-controlled synthesis of nanostructured photocatalysts by an environmentally friendly and low-cost method provides a feasible way to realize practical applications of photocatalysts. Herein, Bi2WO6 (BWO) nanophotocatalysts with mulberry shape, sheet-like, and round-cake morphologies have been successfully synthesized through a highly facile solvothermal process by simply adjusting the solvothermal temperature or utilizing selective addition of ethylene glycol as an orientation agent without using strong acids and bases and/or hazardous chemicals. The ratio of ethylene glycol and glacial acetic acid can affect the morphology and oxygen vacancy content of BWO, thereby influencing the photocatalytic performance. The photocatalytic activity of the as-prepared samples was evaluated by degradation of rhodamine B (RhB) and tetracycline under visible-light irradiation. The results indicated that all the BWO samples exhibited morphology-associated photocatalytic activity, and the sheet-like structure of BWO obtained via solvothermal treatment at 120 °C with ethylene glycol and glacial acetic acid ratio of 1:3 achieved the maximum specific surface area and possessed abundant oxygen vacancies, exhibiting outstanding photocatalytic activity for degradation of RhB and tetracycline. The degradation rate of RhB reached 100% within 20 min. To the best of our knowledge, this value is one of the most remarkable values for pristine BWO photocatalysts. Radical capture experiments demonstrated that hydroxyl radicals (·OH) play major roles compared with electrons (e−) and holes (h+) in the photocatalytic degradation process. A possible mechanism for the photocatalytic degradation of pollutants was proposed to better understand the reaction process. We believe that the more economical, efficient and greener methodology can provide guidance to develop highly efficient photocatalysts with favourable morphology and structure. [ABSTRACT FROM AUTHOR]

In this work, BiFe0.91Zr0.09O3 (BFZrO) films are successfully prepared on ITO/glass substrates via sol–gel synthesis. The effects of different annealing atmospheres (air, O2, and N2) on the crystal structure; defect concentration; and ferroelectric, photovoltaic, and aging performances of the BFZrO samples are studied, and related mechanisms are analyzed in detail. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses reveal that all samples exhibit a two-phase structure composed of rhombohedral R3c and orthorhombic Pnma phases with different contents. X-ray spectroscopy (XPS) and scanning electron microscopy (SEM) analyses indicate that annealing under an O2 atmosphere significantly reduced the concentrations of oxygen vacancy and Fe2+ defects in the films, and is more beneficial to grain growth. Samples annealed in O2 demonstrate lower leakage currents (4.83 × 10−6 A cm−2) and higher remanent polarization strengths (2Pr = 70.26 μC cm−2) than those prepared in air or N2. Furthermore, annealing in O2 improves the optical absorption and photovoltaic performance of BFZrO films, which reduced the band gap (Eg) to 2.65 eV and a doubled short-circuit current density (JSC). Energy band diagrams of Au/BFZrO/ITO structures are constructed from analysis of ultraviolet photoelectron spectra (UPS) and ultraviolet-visible (UV-vis) spectra to explain the mechanisms by which the annealing atmosphere influences the photovoltaic performance. Aging of BFZrO films is found to closely relate to the oxygen vacancy content and mechanisms of domain pinning, so the O2-rich annealing treatment provides an effective means to enhance the film stability. [ABSTRACT FROM AUTHOR]

BiFe1−xZrxO3 (x = 0, 3, 6, 9, 12 mol%) (BFZrO) films were prepared via the sol–gel method by applying ITO/glass as substrates. The influence of different Zr doping amounts on the crystal structure, oxygen vacancy content, leakage mechanism and optical, ferromagnetic, ferroelectric and aging properties of the BFZrO films was investigated. XRD and Raman results showed that all the BFZrO (0–12 mol%) films are composed of rhombohedral (R3c space group) and orthorhombic (Pnma space group) phases, and with increasing Zr content, the R3c phase content of the BFZrO films gradually decreases while the Pnma phase content gradually increases. SEM and XPS results showed that Zr doping resulted in smaller and more uniform grains of the BFZrO films, and the oxygen vacancy and Fe2+ contents decreased. Zr doping reduced the leakage current density, increased the band gap, improved the ferromagnetic property and degraded the ferroelectric property of the BFZrO thin films. The changes in the above properties are explained from the perspectives of the changes in the two-phase contents, oxygen vacancy concentration, grain size and so on. Due to the aging being related to the oxygen vacancy concentration and the rearrangement of the defect dipoles, the aging degree of BFO films was significantly reduced by Zr doping. [ABSTRACT FROM AUTHOR]

BiFe1−xZnxO3 (x = 0, 0.5, 1, 1.5, 2 mol%) (BFZO) films were prepared on ITO/glass substrates by a sol‐gel method. The effects of different Zn contents on the structures and electrical properties of the BFZO films were investigated. From X‐ray diffraction (XRD), microstructure and X‐ray spectroscopy (XPS) results, the BFZO films with a Zn content of 1 mol% showed a better crystal structure and grain development, and the Fe2+ and oxygen vacancy concentrations in this sample were the lowest among all the evaluated BFZO films. The P‐E hysteresis loop indicated that the BFZO films with 1 mol% Zn had the highest remanent polarization (2Pr), which was 82.4 μC/cm2, along with a coercive field (2Ec) of 887 kV/cm at the tested electric field of 857 kV/cm. The BFZO film with 1 mol% Zn had the lowest leakage current density, which was 3.54 × 10−7 A/cm2 at the tested electric field of 200 kV/cm. Both at high and low electric fields, the space charge‐limited current (SCLC) conduction mechanism was the main leakage mechanism. When the test frequency was 105 Hz, the dielectric constant was 133, and the dissipation factor was 0.015. [ABSTRACT FROM AUTHOR]

This study examined the effect of Ca doping on the properties of Sr2Bi4Ti5O18 (SBTi) ferroelectric thin films. According to the results of the study, the performance of SBTi thin films are improved by suitable Ca doping. It can be seen from XRD analysis, all of the thin films formed a bismuth layered perovskite structure without other impure phases. SEM shows that the sample with a doping content of 10 mol% has good crystallization, uniform grain size and good film density. Compared with the characteristics of other films, the thin film sample with 10 mol% Ca shows high crystallinity, the lowest Ti3+ content, the lowest oxygen vacancy concentration, and with the large remanent polarization 2Pr = 33.5 μC/cm2, the double coercive field 2Ec = 182.8 kV/cm; furthermore, the leakage current density is 1.67 × 10−7 A/cm2. The film sample doped with 10 mol% Ca also displays better dielectric properties, with a larger dielectric constant (εr = 795) and lower dielectric loss (tanδ = 0.03) when the test frequency is 105 Hz. The dielectric tunability T = 18.6% at 200 kV/cm and 500 kHz. [ABSTRACT FROM AUTHOR]

Bi1−xSmxFe0.98Mn0.02O3 (x = 0, 0.02, 0.04, 0.06; named BSFMx) (BSFM) films were prepared by the sol-gel method on indium tin oxide (ITO)/glass substrate. The effects of different Sm content on the crystal structure, phase composition, oxygen vacancy content, ferroelectric property, dielectric property, leakage property, leakage mechanism, and aging property of the BSFM films were systematically analyzed. X-ray diffraction (XRD) and Raman spectral analyses revealed that the sample had both R3c and Pnma phases. Through additional XRD fitting of the films, the content of the two phases of the sample was analyzed in detail, and it was found that the Pnma phase in the BSFMx = 0 film had the lowest abundance. X-ray photoelectron spectroscopy (XPS) analysis showed that the BSFMx = 0.04 film had the lowest oxygen vacancy content, which was conducive to a decrease in leakage current density and an improvement in dielectric properties. The diffraction peak of (110) exhibited the maximum intensity when the doping amount was 4 mol%, and the minimum leakage current density and a large remanent polarization intensity were also observed at room temperature (2Pr = 91.859 μC/cm2). By doping Sm at an appropriate amount, the leakage property of the BSFM films was reduced, the dielectric property was improved, and the aging process was delayed. The performance changes in the BSFM films were further explained from different perspectives, such as phase composition and oxygen vacancy content. [ABSTRACT FROM AUTHOR]

The risk of flammability is an unavoidable issue for gel polymer electrolytes (GPEs). Usually, flame-retardant solvents are necessary to be used, but most of them would react with anode/cathode easily and cause serious interfacial instability, which is a big challenge for design and application of nonflammable GPEs. Here, a nonflammable GPE (SGPE) is developed by in situ polymerizing trifluoroethyl methacrylate (TFMA) monomers with flame-retardant triethyl phosphate (TEP) solvents and LiTFSI-LiDFOB dual lithium salts. TEP is strongly anchored to PTFMA matrix via polarity interaction between -P = O and -CH 2 CF 3 . It reduces free TEP molecules, which obviously mitigates interfacial reactions, and enhances flame-retardant performance of TEP surprisingly. Anchored TEP molecules are also inhibited in solvation of Li + , leading to anion-dominated solvation sheath, which creates inorganic-rich solid electrolyte interface/cathode electrolyte interface layers. Such coordination structure changes Li + transport from sluggish vehicular to fast structural transport, raising ionic conductivity to 1.03 mS cm -1 and transfer number to 0.41 at 30 °C. The Li|SGPE|Li cell presents highly reversible Li stripping/plating performance for over 1000 h at 0.1 mA cm -2 , and 4.2 V LiCoO 2 |SGPE|Li battery delivers high average specific capacity > 120 mAh g -1 over 200 cycles. This study paves a new way to make nonflammable GPE that is compatible with Li metal anode., (© 2024. The Author(s).)

Bi 1 -x Sm x Fe 0. 98 Mn 0 .02 O 3 (x = 0, 0.02, 0.04, 0.06; named BSFMx) (BSFM) films were prepared by the sol-gel method on indium tin oxide (ITO)/glass substrate. The effects of different Sm content on the crystal structure, phase composition, oxygen vacancy content, ferroelectric property, dielectric property, leakage property, leakage mechanism, and aging property of the BSFM films were systematically analyzed. X-ray diffraction (XRD) and Raman spectral analyses revealed that the sample had both R3c and Pnma phases. Through additional XRD fitting of the films, the content of the two phases of the sample was analyzed in detail, and it was found that the Pnma phase in the BSFMx = 0 film had the lowest abundance. X-ray photoelectron spectroscopy (XPS) analysis showed that the BSFMx = 0.04 film had the lowest oxygen vacancy content, which was conducive to a decrease in leakage current density and an improvement in dielectric properties. The diffraction peak of (110) exhibited the maximum intensity when the doping amount was 4 mol%, and the minimum leakage current density and a large remanent polarization intensity were also observed at room temperature (2Pr = 91.859 μC/cm 2 ). By doping Sm at an appropriate amount, the leakage property of the BSFM films was reduced, the dielectric property was improved, and the aging process was delayed. The performance changes in the BSFM films were further explained from different perspectives, such as phase composition and oxygen vacancy content.