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Long‐lasting hydrogen evolution and efficient dew harvest is realized via electrospinning a polyvinylidene fluoride (PVDF) membrane on hybrid hydrogels embedded with photocatalytic g‐C3N4/Pt nanosheets. Due to the hindrance of water evaporation by the hydrophobic PVDF membrane, the drying process of the hybrid hydrogels significantly slows down. Hence, the g‐C3N4/Pt nanosheets can continue working on photocatalytic splitting of the water molecules in the hydrogels. When the thickness of the PVDF membrane is 48 μm, the hydrogen evolution rate can reach 2,543 μmol h−1 g−1, which is 38% more than that of the hybrid hydrogel without covering. Therefore, the hybrid hydrogels covered with PVDF membrane are able to work with high efficiency for 12 h, sufficient for hydrogen evolution during the daytime. In addition, the hydrophobic PVDF membrane and hydrophilic hydrogels construct a Janus structure and induce a fast transport of water molecules from the hydrophobic to hydrophilic side. It is beneficial for the rapid collection of dew in the morning. Based on the long‐lasting hydrogen evolution and efficient dew harvest, the present hybrid hydrogels covered with PVDF membrane are very suitable for the environment rich in solar resource and lack of water supply, such as desert or prairie. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (ZIBs) exhibit great potential for next‐generation energy storage devices. However, significant challenges exist, including the uncontrollable formation of Zn dendrite and side reactions during zinc stripping and plating. The mechanism of Zn dendrite nucleation has yet to be fully understood. In this work, the first principles simulations are used to investigate the Zn dendrite formation process. The unintentionally adsorbed O2− and OH− ions are the inducing factors for Zn dendrite nucleation and growth on the Zn (0001) plane due to significantly increased Zn diffusion barriers. A top‐down method is demonstrated to suppress the dendrite using delaminated V2CTx to capture O2− and OH− ions thanks to reduced Zn diffusion barriers. The experimental results revealed significantly suppressed Zn dendrite nucleation and growth, resulting in a layer‐by‐layer deposit/stripping of Zn. Based on the electrochemical evaluations, the V2CTx‐coated Zn composite delivers a high coulombic efficiency of 99.3% at 1.0 mAh cm−2. Furthermore, the full cell achieves excellent cyclic performance of 93.6% capacity retention after 2000 cycles at 1 A g−1. This strategy has broad scalability and can be widely applied in designing metallic anodes for rechargeable batteries. [ABSTRACT FROM AUTHOR]

Solid polymer electrolyte‐based batteries show great promise because of their safe operating properties, wide voltage window and suitable flexibility. However, low ionic conductivity, low cation transfer number, weak oxidation/reduction resistance and low mechanical strength limit their implementation in Zn ion batteries. Here, w e developed a "polymer‐in‐salt" Zn2+‐conductive solid electrolyte (denoted as 70% salt‐SPE) constructed by a simple and fast phase transition method. The room‐temperature ionic conductivity and the transfer number of the 70% salt‐SPE reaches 1.6 mS cm−1 and 0.78, respectively. Meanwhile, the ZnF2‐rich inorganic/organic hybrid solid electrolyte interface is formed, and the stable voltage window reaches 9.35 V. In consequence, the Zn||Zn symmetric cell continuously cycles over 700 hours at current density of 2 mA cm−2 and the Zn||Cu symmetric battery runs with Coulombic efficiency of >99%. The Zn||MnPBA full battery delivers a discharge specific capacity of 109 mAh g−1 at room temperature and 190 mAh g−1 at 60 °C. Meanwhile, impressive cyclic stability of 6000 cycles with capacity retention of 80% is achieved, which originates from the effectively optimized ion transport action and dendrite‐free Zn plating/stripping. [ABSTRACT FROM AUTHOR]

Inspired by the lady costume from Tang Dynasty, printable tattoos are prepared from hybrid nanogels to monitor ultraviolet (UV) radiation from sunshine. The hybrid poly(di(ethyleneglycol) methylether methacrylate‐co‐poly(ethylene glycol) methylethermethacrylate) nanogels containing graphitic carbon nitride (g‐C3N4) nanosheets, abbreviated as hybrid P(MA‐co‐MA300)/g‐C3N4 nanogels, are prepared by precipitation polymerization. Due to the excellent photocatalysis of the g‐C3N4 nanosheets, the dyed hybrid nanogels can be rapidly photodegraded under sunshine. Based on the linear correlation between the discoloration of dyed hybrid nanogels and the dose of solar radiation, the UV radiation from sunshine can be simply monitored by checking the color in real‐time. By applying different types of dyes, the hybrid nanogels even can be used to trace the dose for the synthesis of vitamin D, induction of erythema and risk of skin cancer simultaneously. Favored by the stickiness of acrylate‐based polymers, the hybrid nanogels can be printed to the body as tattoos to realize decoration and UV detection. By simply switching the template for printing, the tattoo patterns can be easily changed according to personal interests and applied position on the human body. Therefore, the present hybrid nanogels can be a promising candidate to monitor the solar radiation dose and decorate the human body. [ABSTRACT FROM AUTHOR]

An adhesive and visualized hydrogel‐based detector is designed to monitor the solar radiation dose required for plant growth by the discoloration of methylene blue (MB) under sunshine. The detector is based on hybrid hydrogels prepared from photoinitiated polymerization. The combination of polypropylene (PP) fabrics acting as a substrate and the photoinitiated polymerization on the graphitic carbon nitride (g‐C3N4) surface enables a smaller thickness and a more homogenous distribution of the g‐C3N4 nanosheets. Thus, the hybrid interpenetrating network (IPN) hydrogel on the PP fabrics with a thickness of 1.5 mm presents an improved photodegradation capability. In addition, better mechanical properties and lower weight of the hydrogel‐based detector are achieved by the presence of the PP fabrics. In combination with the stickiness from a polyurethane resin acting as glue, the obtained detector can be easily pasted on the leaf of a plant as demonstrated for the example of Epipremnum aureum. The radiation dose exposed to the leaves can be accurately traced from the change in color of the detector to ensure a sufficient radiation for plant growth and avoid possible burn to the leaves under sunshine. [ABSTRACT FROM AUTHOR]

The photocatalytic water splitting capability of metal‐free graphitic carbon nitride (g‐C3N4) photocatalyst is determined by its microstructure and photoexcited electrons transfer. Herein, a segmented structure was developed, consisting of alternant g‐C3N4 nanotubes and graphitic carbon rings (denoted as Cr‐CN‐NT). The Cr‐CN‐NT showed ordered structure and ultralong length/diameter ratio of 150 nm in diameter and a few microns in lengths, which promoted electron transport kinetics and elongated photocarrier diffusion length and lifetime. Meanwhile, the local in‐plane π‐conjugation was formed and extended in Cr‐CN‐NT, which could improve charge carrier density and prohibit electron–hole recombination. Accordingly, the average hydrogen evolution rate of Cr‐CN‐NT reached 9245 μmol h−1 g−1, which was 61.6 times that of pristine CN, and the remarkable apparent quantum efficiency (AQE) of Cr‐CN‐NT reached up to 12.86 % at 420 nm. This work may provide a pathway for simultaneous morphology regulation and in‐plane modification of high‐performance photocatalysts. [ABSTRACT FROM AUTHOR]

We systematically investigate the combined effect of both the defects, including single vacancy defects (SV) and Stone‐Wales defects (SW), and the decoration of Pt atom on the structural, electronic, and adsorption properties of graphene for SO2 molecule using the density functional theory (DFT). The calculations reveal that Pt atom can be stably combined on both SV defected graphene (SVG) and SW defected graphene (SWG) with the high‐binding energy of −7.03 and −2.61 eV, respectively. In addition, the SO2 molecule is chemically adsorbed on Pt‐decorated graphene with SV defects and SW defects, their adsorption energies are −1.402 and −1.891 eV, respectively. The adsorption of SO2 can significantly change the conductivity of the adsorbed system, which shows that Pt decorated SVG and SWG have good sensitivity to SO2. Moreover, compared with Pt decorated SVG, Pt decorated SWG has better adsorption ability for SO2 gas molecules, which corresponds to larger adsorption energy, strong orbital hybridization, and the obvious increase of conductivity. These results indicate that the combination of defects and Pt atom decoration can tune the electronic and adsorption properties of graphene, and provide insight into the application of graphene‐based gas sensors for SO2 gas molecules. [ABSTRACT FROM AUTHOR]

The sodium ion intercalated ultrathin δ‐MnO2 flakes (abbreviated as NaxKMO) are synthesized by one‐step hydrothermal synthesis. Benefiting from the synergistic effect of sodium ion intercalating process and the homogeneous few‐layered microstructure, the NaxKMO electrode shows increased electron conduction as well as largely enhanced intercalation capacitive performance of 324.2 F g−1 at 0.5 A g−1 and 40.91 % capacitance retention at 8 A g−1 is obtained. Meanwhile, the 91.9 % diffusion contribution for NaxKMO electrode is clarified to be higher than that of KMO electrode, which indicates the preintercalated sodium ions caused a promoted diffusion‐controlled kinetic in charge‐discharge processes for the NaxKMO electrode. An asymmetric supercapacitor device (ASC) is assembled with the NaxKMO cathode and activated carbon anode. With a voltage window of 1.6 V, the fabricated ASC device delivers a high energy and power densities of 31.2 Wh kg−1 and 1571 W kg−1, respectively. With the continuous charge‐discharge tests, the device demonstrates outstanding capacitance retention of 98.2 % after 5000 cycles at 1 A g−1, suggesting a great potential of sodium ion intercalated MnO2 film electrodes in practical applications. [ABSTRACT FROM AUTHOR]

Abstract: A new type of (0.7−x)Bi0.5Na0.5TiO3‐0.3Sr0.7Bi0.2TiO3‐xLaTi0.5Mg0.5O3 (LTM1000x, x = 0.0, 0.005, 0.01, 0.03, 0.05 wt%) lead‐free energy storage ceramic material was prepared by a combining ternary perovskite compounds, and the phase transition, dielectric, and energy storage characteristics were analyzed. It was found that the ceramic materials can achieve a stable dielectric property with a large dielectric constant in a wide temperature range with proper doping. The dielectric constant was stable at 2170 ± 15% in the temperature range of 35‐363°C at LTM05. In addition, the storage energy density was greatly improved to 1.32 J/cm3 with a high‐energy storage efficiency of 75% at the composition. More importantly, the energy storage density exhibited good temperature stability in the measurement range, which was maintained within 5% in the temperature range of 30‐110°C. Particularly, LTM05 show excellent fatigue resistance within 106 fatigue cycles. The results show that the ceramic material is a promising material for temperature‐stable energy storage. [ABSTRACT FROM AUTHOR]

Abstract: The (1−x)(0.8Bi1/2Na1/2TiO3–0.2Bi1/2K1/2TiO3)−xBiMg2/3Nb1/3O3 (100xBMN) ternary solid solutions were designed and prepared using a conventional solid‐state reaction. Temperature and compositional dependent ferroelectric, piezoelectric, dielectric features, and structural evolution were systematically studied. At the critical composition of 2BMN, a large bipolar strain of 0.43% was achieved at 55 kV/cm, and the normalized strain reaches to 862 pm/V at a low driving electric field of 40 kV/cm. It was found that the substitution of BiMg2/3Nb1/3O3 induces a transformation from ferroelectric to relaxor phase by disrupting the long range ferroelectric order. Therefore, as the external electric field was applied, a relaxor‐ferroelectric phase transition will be induced. This is contributed to the giant strain. The results above suggest that such a ternary composition is a promising candidate for application to actuator. [ABSTRACT FROM AUTHOR]

Abstract: As an amorphous or semicrystalline material, graphitic carbon nitride (g‐C3N4) displays poor photocatalytic activity owing to rapid recombination of the photogenerated charge carriers, which is mainly caused by a high density of defects in the graphitic structure. In this work, a porous O‐doped g‐C3N4 (P‐CNO) nanosheet with a highly ordered architecture is fabricated by introducing a novel hydrothermal treatment to the precursor before the final thermal condensation. The photocatalytic hydrogen evolution rate (HER) and HER per surface area of P‐CNO are 13.9 and 1.7 times higher than that of bulk g‐C3N4. The improved photocatalytic activity is ascribed to a synergistic effect of O doping, a porous sheet‐like morphology, and increased crystallinity. This work also provides a new approach for the synthesis of other polymer‐based photocatalysts with high crystallinity and excellent performance. [ABSTRACT FROM AUTHOR]

The (Na0.484Bi0.456Ba0.06)Ti0.97Nb0.03O3 − xLi+ ( x = 0, 0.005, 0.01, 0.015) lead-free piezoelectric ceramics are prepared by conventional solid-state reaction technique. X-ray diffraction and surface scanning electron microscope images confirm the pure perovskite structure of sintered ceramics. Electric field and composition-dependent strain behavior are investigated. The highest bipolar strain of 0.47% is achieved at x = 0.01 with the applied electric-field of 70 kV cm−1, and the corresponding normalized strain ( [ABSTRACT FROM AUTHOR]

x% mol MnO2-doped Ba0.925Ca0.075TiO3 ceramics (abbreviated as BCT-Mn x, x=0-1.5) were synthesized by conventional solid-state reaction method. The effects of MnO2 addition and (Ba+Ca)/Ti mole ratio (A/B ratio) on the microstructure and electrical properties of the ceramics were investigated. The internal bias filed Ei was determined from the asymmetrical polarization hysteresis loops and found to increase with the doping concentration of MnO2. High mechanical quality factors ( Qm>1200) and low dielectric loss (tanδ<0.5%) were found in the BCT-Mn0.75 and BCT-Mn1.0 ceramics with Ei>3 kV/cm, meanwhile, the piezoelectric and electromechanical properties were found to decrease compared with the pure BCT, exhibiting a typical characteristic of 'hard' behavior. Of particular interest is that the microstructure of BCT-Mn0.75 ceramics could be controlled by changing the A/B ratio, where enhanced piezoelectric coefficient d33 on the order of 190 pC/N was obtained in the BCT-Mn0.75 ceramics with A/B=1.01 due to its fine-grained microstructure, with yet high Qm , being on the order of 1000. The high d33 and Qm in MnO2-doped BCT ceramics make it a promising candidate for high power piezoelectric applications. [ABSTRACT FROM AUTHOR]

The dielectric, piezoelectric properties, and fatigue behaviors of stoichiometric (Bi0.5+ x/2Na0.5- x/2)0.94Ba0.06Ti1- xFe xO3 ( BNBT- xFe) ferroelectrics are investigated. Fe substitution leads to the downward shift of the ferroelectric-relaxor transition temperature ( TF-R) and increase in strain. Meanwhile, fatigue behaviors of the modified ceramics are significantly enhanced. Ex situ X-ray diffraction and transmission electron microscopy reveal microscopic mechanism for polarization fatigue on different compositions. The fatigue-free behavior of ferroelectric BNBT-0.03Fe is not only attributed to a mechanism involving the formation of defect dipoles, which reduces the pinning effect of migratory oxygen vacancies on domain walls, but is also connected to the decrease in easily suppressed field-induced ferroelectric tetragonal phase. While for ergodic relaxor BNBT -0.09Fe, the absence of domain wall contributes to the good fatigue resistance behavior. Interestingly, electric cycling results in an increased fraction of relaxor phase, accompanying by the increase in the total strain and decrease in remnant polarizations. [ABSTRACT FROM AUTHOR]

xSrTiO3-(1− x)LaAlO3 ceramics with ZnO-B2O3 sintering aid were prepared by solid-state reaction method leading to a significant decrease in sintering temperature from 1550°C to 1050°C. The structure, microwave dielectric properties, and low-temperature sintering behavior were systematically investigated. The results revealed the relationships among ionic size, ionic polarizability and cell volume. With increasing additive, chemical ordering of B-site cations was indicated with selected area electron diffraction ( SAED) patterns, HRTEM images and Raman spectrum, which contributed to the greatly enhanced microwave dielectric properties. Particularly, the 0.7Sr0.85 Mg0.15TiO3-0.3LaAlO3 ceramics modified with 10 wt % ZnO-B2O3 can further decrease the sintering temperature down to 950°C without deteriorating its performance. Thermal tests implied ceramics featured good chemical compatibility with Cu/Ag electrode. Thus, they can be cofired with internal Cu/Ag electrodes in special patterns to fulfill different electrical functions for LTCC (low-temperature cofired ceramic) application. [ABSTRACT FROM AUTHOR]

We surveyed the group B Streptococcus ( GBS) strains isolated from four teaching hospitals during 1-year period to investigate the current serotypes and antimicrobial resistance status of these strains. A total of 231 non-duplicate colonizing GBS isolates were collected from pregnant women. Antimicrobial susceptibility of these isolates was tested by the disk diffusion method. Serotype was performed by a multiplex polymerase chain reaction ( PCR) method. Analysis of the resistance mechanisms was performed by PCR amplification and DNA sequencing. Seven serotypes (Ia, Ib, II, III, V, VI, and VIII) were identified, and the prevalence ranged from 0.9 to 35.9%. All isolates were susceptible to the penicillin, ceftriaxone, and vancomycin. The resistance of all the isolates to erythromycin, clindamycin, and levofloxacin was 61.5, 51.9, and 35.5%, respectively. The erythromycin resistance was mainly associated with the genes ermB and ermB-mef(A/E) (69.8%). The most predominant phenotype was cMLSB (77.5%). Five gene panels, including gyrA, parC, parE, gyrA-parC, and gyrA-parC-parE, were detected. The most predominant genotype was gyrA-parC-parE triple mutation (69.5%). The S81L in gyrA gene, S79Y mutation in parC gene, and H225Y mutation in parE gene were discovered. The isolates with serotype III, V, and Ia were the most important clone concerning the prevalence and resistance. [ABSTRACT FROM AUTHOR]

Pure perovskite K0.5Na0.5NbO3- xSrTiO3 ( x = 0.16, 0.17, 0.18, and 0.19) ceramics were prepared by using a solid-state reaction process. The ceramics were optically transparent for visible and near-infrared wavelengths. Then, high tunability (24.1%) and low dielectric loss (0.016) for the x = 0.18 sample indicated the transparent ceramics could be used in tunable devices. The Lorentz-type relation fitting for the temperature dependence of dielectric permittivity showed that these ceramics had a typical relaxor behavior, and the polar nanoregions were related to the tunable dielectric properties. The nonlinear dielectric behavior was further explored by the Johnson model combined with Langevin terms, which revealed that the polar nanoregions contributed to the nonlinear ε( E) dependencies with contributions of 12.3%, 11.6%, 5.9%, and 3.6% for x = 0.16, 0.17, 0.18, and 0.19, respectively. [ABSTRACT FROM AUTHOR]

Ternary solid solutions of (1 − x)(0.8Bi0.5Na0.5TiO3-0.2Bi0.5K0.5TiO3)- xNaNbO3 (BNKT- xNN) lead-free piezoceramics were fabricated using a conventional solid-state reaction method. Pure BNKT composition exhibited an electric-field-induced irreversible structural transition from pseudocubic to ferroelectric rhombohedral phase at room temperature. Accompanied with the ferroelectric-to-relaxor temperature TF-R shifted down below room temperature as the substitution of NN, a compositionally induced nonergodic-to-ergodic relaxor transition was presented, which featured the pinched-shape polarization and sprout-shape strain hysteresis loops. A strain value of ~0.445% (under a driving field of 55 kV/cm) with large normalized strain of ~810 pm/V was obtained for the composition of BNKT-0.04 NN, and the large strain was attributed to the reversible electric-field-induced transition between ergodic relaxor and ferroelectric phase. [ABSTRACT FROM AUTHOR]

The field dependence of ferroelectric hysteresis loop and polarization reversal of 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 (BNT-6BT) ferroelectrics at room temperature and 110 °C are investigated. The variation of the hysteresis area suggests three stages of the polarization reversal at the two temperatures, where the first and third stage can be scaled as power law relationships, and the second stage shows non-linear functions. Distinct features in the two temperatures indicate the differences between the domain structures and their external field responses. The reversible field-induced phase transition from relaxor phase to ferroelectric phase at 110 °C plays a key role in getting the large strain. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectrics (0.94 − x)( Bi0.5 Na0.5) TiO3-0.06 BaTiO3− x( Sr0.7 Bi0.2□0.1) TiO3 ( BNT- BT- x SBT) (0 ≤ x ≤ 0.5), were prepared by a solid-state reaction process, and their structures were characterized by the transmission electron microscopy and Raman spectroscopy. The BNT- BT-0.3 SBT has a very high electrostrictive strain S = 0.152% with hysteresis-free behavior, much more than the reported S in other ferroelectrics. S- P2 profiles perfectly follow the quadratic relation, which indicates a purely electrostrictive effect with a high electrostrictive coefficient ( Q11) of 0.0297 m4/C2. Even, its Q11 keeps at a high level in the temperature range from ambient temperature to 180°C. The field-induced large electrostrictive strain of BNT- BT-0.3 SBT was attributed to the existence of ferroelectric nanodomains. [ABSTRACT FROM AUTHOR]

Recently, large electrocaloric effects (ECE) in antiferroelectric sol-gel PbZr0.95Ti0.05O3 thin films and in ferroelectric polymer P(VDF-TrFE)55/45 thin films were observed near the ferroelectric Curie temperatures of these materials (495 K and 353 K, respectively). Here a giant ECE (Δ T = 45.3 K and Δ S = 46.9 J K−1 kg−1 at 598 kV cm−1) is obtained in relaxor ferroelectric Pb0.8Ba0.2ZrO3 (PBZ) thin films fabricated on Pt(111)/TiOx/SiO2/Si substrates using a sol-gel method. Nanoscale antiferroelectric (AFE) and ferroelectric (FE) phases coexist at room temperature (290 K) rather than at the Curie temperature (408 K) of the material. The giant ECE in such a system is attributed to the coexistence of AFE and FE phases and a field-induced nanoscale AFE to FE phase transition. The giant ECE of the thin film makes this a promising material for applications in cooling systems near room temperature. [ABSTRACT FROM AUTHOR]

Aurivillius piezoelectrics, Bi-Sc modified Na0.5- xBi2.5+ xNb2- xSc xO9 ( x = 0.05 and 0.1) and Na-deficient and Bi-enriched Na0.5- xBi2.5+ xNb2O9 ( x = 0.05, 0.1, and 0.2), were prepared by using a solid-state reaction process. The Rietveld refinement verified that Sc3+ and excess Bi3+ were incorporated into the layered perovskite structure and that they occupied the B and A sites, respectively. The Na0.45Bi2.55Nb1.95Sc0.05O9 [0.05(BiSc)-modified] crystallized in the orthorhombic space group A21 am [ a = 5.49853(9) Å, b = 5.45976(9) Å, c = 24.98351(29) Å, and V = 750.021(20) Å3; Z = 4] at room temperature. The A-site Bi3+ donor substitution induced no obvious increase in the Curie point ( Tc), but a further Sc3+ modification at the B site gave rise to a significant increase in Tc. The movements of non-180° domains contributed to the piezoelectric activities of the Bi-excess polycrystalline materials, whereas the excellent piezoelectric properties of the Bi-Sc-modified polycrystalline materials mostly originated from intrinsic lattice contributions, which are due to their single-180°-domain-wall structures. The Na0.45Bi2.55Nb1.95Sc0.05O9 [0.05(BiSc)-modified] polycrystalline materials have a high Tc of 811 °C and a high piezoelectric activity ( d33) of 28 pC/N; interestingly, its d33 was very stable against temperature. [ABSTRACT FROM AUTHOR]

Aurivillius piezoelectrics, Bi-Sc modified Na0.5- xBi2.5+ xNb2- xSc xO9 ( x = 0.05 and 0.1) and Na-deficient and Bi-enriched Na0.5- xBi2.5+ xNb2O9 ( x = 0.05, 0.1, and 0.2), were prepared by using a solid-state reaction process. The Rietveld refinement verified that Sc3+ and excess Bi3+ were incorporated into the layered perovskite structure and that they occupied the B and A sites, respectively. The Na0.45Bi2.55Nb1.95Sc0.05O9 [0.05(BiSc)-modified] crystallized in the orthorhombic space group A21 am [ a = 5.49853(9) Å, b = 5.45976(9) Å, c = 24.98351(29) Å, and V = 750.021(20) Å3; Z = 4] at room temperature. The A-site Bi3+ donor substitution induced no obvious increase in the Curie point ( Tc), but a further Sc3+ modification at the B site gave rise to a significant increase in Tc. The movements of non-180° domains contributed to the piezoelectric activities of the Bi-excess polycrystalline materials, whereas the excellent piezoelectric properties of the Bi-Sc-modified polycrystalline materials mostly originated from intrinsic lattice contributions, which are due to their single-180°-domain-wall structures. The Na0.45Bi2.55Nb1.95Sc0.05O9 [0.05(BiSc)-modified] polycrystalline materials have a high Tc of 811 °C and a high piezoelectric activity ( d33) of 28 pC/N; interestingly, its d33 was very stable against temperature. [ABSTRACT FROM AUTHOR]

Using a sol-gel method Pb0.8 Ba0.2 ZrO3 ( PBZ) thin film with a thickness of ~320 nm was fabricated on Pt(111)/ TiO x/ SiO2/ Si substrate. The analysis results of XRD, SEM, and dielectric properties revealed that this thin film is a (111)-oriented nano-scaled antiferroelectric and ferroelectric two-phase coexisted relaxor. Calculations of dielectric tunability (η) and figure-of-merit ( FOM) at room temperature display a maximum value of 75% at E = 560 kV/cm and ~236, respectively. High-temperature stability (η > 75% and FOM > 230 at 560 kV/cm in the range from 300 to 380 K) and high breakdown dielectric strength (leakage current < 1 nA at 598 kV/cm) make the PBZ thin film to be an attractive material for applications of tunable devices. [ABSTRACT FROM AUTHOR]

Pure perovskite Pb( Mg1/3 Nb2/3)1− x Ti x O3 ( x = 0, 0.01, 0.03, 0.05, 0.07, 0.09) ceramics were prepared using a two-stage solid state reaction process. With the increase of Ti content, the dielectric tunability and dielectric loss at x = 0.09, 25 kV/cm and 300 K reached a maximum 91% and 0.09, respectively. High dielectric tunability 82% with low dielectric loss 0.007 was obtained at x = 0.05, indicating that it is a promising tunable material. The Lorentz fit of the temperature dependence of the dielectric permittivity and the measurement of the temperature dependence of the depolarization current density showed that polar nanoregions are related to the dielectric tunability properties of these relaxor ferroelectric ceramics. The Landau-Ginsberg-Devonshire and multipolarization-mechanism model fitted results of the electric field dependence of the dielectric permittivity showed that the contribution of the 'extrinsic' polarizations including 'reorientation of nanopolar clusters' and the 'motion of the cluster interphase boundaries or domain-wall motions' to the dielectric tunability properties increased with the increase of Ti content. These results provide a clear understanding to the complicated dielectric response in a family of high-tunability ceramics and a key to the high tunability of ferroelectrics with low loss under dc electric field. [ABSTRACT FROM AUTHOR]

Ba0.6Sr0.4(Ti1− xMg x)O3 (BSTM) ceramics were prepared by using a solid-state reaction process. X-ray diffraction results indicated that the solubility limit of Mg in Ba0.6Sr0.4TiO3 was about 3 mol%. Doping of Mg into BST led to diffused cubic-tetragonal ( C- T) phase transition and reduced Curie temperature. The diffused parameter γ obtained by fitting the modified Curie-Weiss laws increased with increasing Mg content. Dielectric properties of the BSTM ceramics were measured. Figure of merit of BSTM3 was up to 127.8 at 17.5 kV/cm. Its dielectric loss was as low as 0.00133 at 1 kHz and room temperature. [ABSTRACT FROM AUTHOR]

Highlights With the continuous development of high‐end electronic information technologies such as 5G communications, thermal management is an urgent issue in the electronic and circuit industries due to the miniaturization, functionalization and integration. Recently, polymer‐based composites with the fillers of hexagonal boron nitride (h‐BN) have been regarded as promising candidates resulting from their excellent thermal conductivity (TC), good insulation and remarkable comprehensive properties. However, the high surface inertness of h‐BN itself, incompatibility with matrix and other fillers and mismatch of phonon‐spectrum will bring about the matrix/filler and filler/filler interfacial thermal resistance (ITR), which will greatly decline the TC of the composites, and limit their thermal management ability. Therefore, how to design, regulate and improve the interfacial states in composites and eventually enhance the TC is a current challenge. Researchers have made great effort to reduce the ITR of the composites to improve their TC. However, a comprehensive summary and analysis of researches on the improvement methods of the interface states in composites in the past 3 years is still lacking. In this work, the commonly used mechanism models, and simulation methods for calculating and predicting TC was summarized. From perspectives of Synthesis of h‐BNNs, modification, orientation, bridging and three‐dimensional structures construction, we reviewed strategies for improving the interface states in composites, and focused on the ITR regulation and TC improvement. The improvement effects of various methods on TC were compared. The development trend of high TC composite materials was prospected. Crystallinity, defect, size, flatness, thickness of hexagonal boron nitride nanosheets (BNNSs) affect interfacial thermal resistance (ITR). Nature of interaction between adjacent layers of BNNS need exploited. Interface and defect are root cause of extra phonon scattering. Shape, density, surface area, distribution and compatibility reduce ITR. Theory, model, simulation methods need developed on different levels. [ABSTRACT FROM AUTHOR]

Inspired from seaweed swayed by waves, the enhanced hydrogen evolution is realized in porous and hybrid g‐C3N4/Pt‐PVDF electrospun membranes via piezoelectricity from water flow energy. The membranes are fabricated by dispersing g‐C3N4/Pt into the mixed solution of PVDF and PEO, followed by electrospinning and selective removal of PEO. By changing the PEO amount, the pore size in nanofibers is adjusted. Due to the hydrogen bonding between g‐C3N4/Pt and PVDF, the β phase of PVDF is increased, beneficial for the piezoelectricity performance. When the electrospun membranes are exposed to water flow, an additional potential field is triggered due to the deformation of PVDF. It not only eases the photogeneration of charge carriers from g‐C3N4/Pt but also hinders their recombination. The prolonged lifetime significantly improves the photocatalytic water splitting of g‐C3N4/Pt under visible light. The hydrogen evolution in the electrospun membranes (PVDF to PEO = 4:1) is profoundly improved to 9 278 µmol h−1 g−1, almost doubled to the pure g‐C3N4/Pt nanosheets (5 220 µmol h−1 g−1). Therefore, the seaweed‐inspired electrospun membrane is a promising strategy for the efficiently photocatalytic water splitting via g‐C3N4 in an aqueous environment, such as a natural sea and lake, by the piezoelectricity gained from the water flow energy. [ABSTRACT FROM AUTHOR]

Photonic crystal of packed monodisperse silica submicron spheres were synthesized in this article. We investigated the optical properties of packed monodisperse silica submicron spheres by means of both optical transmission and reflection measurements. Research suggests that the two methods are consistent in essence, and the reflection mode is more suitable for colloidal crystal assembled of smaller colloidal spheres. Accurately tuning of photonic band gap by incident light angle was also studied in our article. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26156 [ABSTRACT FROM AUTHOR]

New high-temperature Aurivillius piezoelectrics Na0.5NdxBi2.5-xNb2O9 (NDBNx, x = 0.1, 0.2, 0.3, and 0.5) are prepared by solid state reaction of a stoichiometric mixture of Bi2O3, Nb2O5, Na2CO3, and Nd2O3 (1. [ABSTRACT FROM AUTHOR]

We systematically investigate the combined effect of both the defects, including single vacancy defects (SV) and Stone‐Wales defects (SW), and the decoration of Pt atom on the structural, electronic, and adsorption properties of graphene for SO2 molecule using the density functional theory (DFT). The calculations reveal that Pt atom can be stably combined on both SV defected graphene (SVG) and SW defected graphene (SWG) with the high‐binding energy of −7.03 and −2.61 eV, respectively. In addition, the SO2 molecule is chemically adsorbed on Pt‐decorated graphene with SV defects and SW defects, their adsorption energies are −1.402 and −1.891 eV, respectively. The adsorption of SO2 can significantly change the conductivity of the adsorbed system, which shows that Pt decorated SVG and SWG have good sensitivity to SO2. Moreover, compared with Pt decorated SVG, Pt decorated SWG has better adsorption ability for SO2 gas molecules, which corresponds to larger adsorption energy, strong orbital hybridization, and the obvious increase of conductivity. These results indicate that the combination of defects and Pt atom decoration can tune the electronic and adsorption properties of graphene, and provide insight into the application of graphene‐based gas sensors for SO2 gas molecules. [ABSTRACT FROM AUTHOR]