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The use of microfluidic fuel cells (μFCs) as power sources in the development of non-implantable biomedical devices, such as patch sensors, could be broadened with the use of physiological fluids as fuels and the use of low-cost materials. In this work, we report the evaluation of a paper-based photo-μFC working with human blood as fuel, and we implement a nanocomposite as anode that presents photoactivity under visible light. The electrocatalyst was synthesized using Zn(NO3)2 and TiCl4 as precursors of the ZnO and the TiO2, respectively, which were coated with Au nanoparticles. It was demonstrated that ZnO and TiO2 nanoparticles consisted of crystals with wurtzite and anatase phases, with average sizes of 26.6 and 19.5 nm, respectively, and the TiO2/ZnO/Au nanocomposite presents 2.62 eV of band gap energy, demonstrating its photoactivity under visible light irradiation. The photocatalyst was tested as photoanode in half-cell for glucose oxidation in aqueous solutions, under illumination and dark conditions, showing characteristics peaks of glucose oxidation in both cases, but higher current was generated under illumination. Finally, we present the implementation of this anode and the construction of a paper-based photo-μFC using human blood as fuel; its performance was evaluated under visible light irradiations and in the dark. The results show a better performance under illumination with voltage, current, and power density values of 0.95 V, 1.2 mA cm−2, and 0.458 mW/cm2, respectively, compared to the corresponding values of 0.8 V, 0.96 mA cm−2, and 0.274 mW/cm2 in dark conditions. [ABSTRACT FROM AUTHOR]

• Two Fe3+ fluorescent probes based D-A type imidazole derivatives have been developed, which possessed a relatively great selectivity and sensitivity. • The probe molecules showed a relatively rare fluorescence color change response to Fe3+, its fluorescence changed from deep-blue to green. • The fluorescence sensing behavior of the probe molecules to Fe3+ was also applied to realize the rewritable paper in a very simple way. D-A type fluorescent probe usually shows a fluorescence quenching response to Fe3+, and relatively few probes can exhibit the fluorescence color change response. Herein, two high-luminescence D-A type imidazole derivatives TPABM and TPAFM were synthesized and used as Fe3+ fluorescent probes with an obvious fluorescence color change and remarkable sensing performance. Upon the addition of Fe3+, the original emission of TPABM and TPAFM was quenched, while a new emission peak emerged in the red-shifted direction, resulting in the fluorescence color changing from deep blue to green. This phenomenon may be caused by the coordination between the molecular imidazole ring and Fe3+ with a 1:1 ratio, which efficiently decreased the LUMO energy level of the probe molecules and formed a new CT emission with a lower energy gap. Furthermore, the probe molecules exhibited the potential for detecting Fe3+ in actual water samples and could be appropriated for the preparation of rewritable paper using a simple method. By using filter paper soaked with probe molecules as writing paper, Fe3+ aqueous solution as ink, and NaF aqueous solution as an eraser, the cycle of fluorescence writing and erasing was realized under UV irradiation. [Display omitted] [ABSTRACT FROM AUTHOR]

We herein demonstrate polypyrrole decorated micro-porous laboratory filter paper (PFP) as photoanode (PA) for efficient and stable water splitting. The straddling band position with water redox and the measured band gap of ~1.98 eV, make these PFP-PAs effective for water splitting reactions. The results manifest excellent photo-anodic PEC activity of these PFP-PAs, yielding a photocurrent density of ~9.5 mA/cm2 (at 1.23 V vs. RHE) in a three-electrode configuration. The incident photon-to-current efficiency (IPCE) and applied bias photon-to-current efficiency (ABPE) was measured to be 43.19% and ~1%, respectively. Moreover, the robustness of these flexible PFP-PAs was visualized by the provided stability for more than ~160 min in alkaline conditions. The current study provides a proof-of-concept for the realization of a cost-effective, flexible, and efficient paper-based artificial catalyst (like a natural leaf) for solar-driven water splitting. Image 1 • In-situ fabricated polypyrrole based flexible filter paper photo electrode (PFP-PEs). • Exhibit a bandgap of ~1.98 eV and reported as PEs for water splitting. • Photocurrent density of ~9.5 mA/cm2 (at 1.23 V vs. RHE) in 3-electrode system. • IPCE and ABPE was measured to be 43.19% and ~1%, respectively. • PFP-PEs stable for 160 min in alkaline conditions for PEC water splitting. [ABSTRACT FROM AUTHOR]

In the current research work "4-{[1-(2,5-dihydroxyphenyl)ethylidene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one" chemosensor (C1) synthesized by condensation reaction using "4-amino-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one" and "2,5-dihydroxy actophenone" was used as the effective sensor of metal ion. The C1 shows absorption peak at 326 nm due to the C = C bond (π-π* transition), while the absorption peak at 364 nm is caused by the C = O bond (n-π* transition). In the presence of copper, C1 only demonstrated a redshift in absorption peak from 364 to 425 nm. Even in the presence of other competing metal ions, the hypsochromic shift of the absorption band and the quenching of the fluorescence emission intensity were different for detecting Cu2+, in CH3OH-H2O (v/v = 6:4). The capacity of the C1 to bind with Cu2+ was further proved using DFT simulations. The complex C1 + Cu2+ has a HOMO–LUMO energy gap of 2.8002 eV, which is lesser than C1 (2.9991 eV) showing improvement in the stability of the C1 + Cu2+ complex. Using the Benesi-Hildebrand and Scatchard plots, calculated Kb values were to be 47,340 and 48369 M−1 respectively, showing the creation of stable complexation between Cu2+ and C1 with 1:1 stoichiometry. The limit of detection (LOD) for Cu2+ ion was 649 nM. Strip sheets were also built and tested to detect varying amounts of Cu2+ in aqueous solution, and their color change suggested that they might be used for on-site Cu2+ detection in polluted water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile and scalable self-assembly of perylene diimide polymer with carbon paper. • Effective facilitation of carrier separation by π-π built-in electric field. • Narrowed band gap and low VB due to the VB tail states induced by π-π interactions. • Enhanced photocatalytic water oxidation activity of the PDIP/CP photocatalyst sheet. • Suitability of the PDIP/CP photocatalyst sheet for large-scale applications. Photocatalytic water splitting is a highly promising future energy technology. In contrast to the extensive work on particulate photocatalysts, there is still a lack of sufficient investigation for regularized photocatalysts. Here, from perylene diimide polymer (PDIP) and commercial carbon paper (CP), we develop a self-assembled PDIP/CP photocatalyst sheet that is easily scalable and can be used for photocatalytic water oxidation. Driven by strong interfacial π-π interactions, the PDIP spontaneously adsorbs onto the CP, which leads to a narrowed band gap, down-shifted VB edge, and enhanced separation of the photogenerated charge carriers of the PDIP. Under visible light, the PDIP/CP photocatalyst sheet shows significantly enhanced photocatalytic water oxidation activity (4 h cumulative oxygen evolution is 1.7 times higher than that of the powder-suspended system) and considerable cycling stability. The PDIP/CP photocatalyst sheet has the potential for large-scale device applications. [ABSTRACT FROM AUTHOR]

A novel colorimetric-fluorescent dual-mode sensing sensor JT5 was successfully synthesized, and exhibited red fluorescence enhancement effect and red colorimetric sensing, and excellent applicability through solid-state fluorescent strips and biological imaging experiments on zebrafish to highly sensitive monitoring Sn4+ ions. [Display omitted] • A novel and effective rhdamine B-based sensor JT5 successful development. • JT5 can serve as a fluorescent and colorimetric on-off sensor for Sn4+. • The sensor JT5 was successfully studied using fluorescence and colorimetric of the test strips. • Biomaging experiments for the sensor JT5 were conducted on zebrafish using a confocal microscope. A novel colorimetric-fluorescent dual-mode chemosensor (JT5) based on rhodamine B has been produced for monitoring Sn4+ in the DMSO/H 2 O (4:1, v/v) medium. It has high sensitivity, a low detection limit, a short response time (1 s) and high stability, and can still be maintained after two weeks with the red dual fluorescence/ colorimetric response. Enhancement of red fluorescence (591 nm) and red colorimetric (567 nm) response of JT5 by Sn4+ addition. The electrostatic potential of the sensor JT5 molecule was simulated to speculate on the sensing mechanism, and the IR, mass spectrometry and 1H NMR titration were utilized to further demonstrate that JT5 was coordinated to Sn4+ with a 1:1 type, the rhodamine spironolactam ring of JT5 opens up to form a penta-membered ring with Sn4+, meanwhile, its system may have chelation enhanced fluorescence (CHEF) effect. In addition, theoretical calculations were carried out to give the energy gaps of JT5 and [ JT5 + Sn4+] as well as to simulate the electronic properties of the maximal absorption peaks. Notably, the sensor JT5 was successfully applied to monitoring Sn4+ in zebrafish, and the JT5 -loaded filter paper provided a solid-state platform for detecting Sn4+ by both naked eye and fluorescent methods. In summary, this work contributes to monitoring Sn4+ in organisms and solid-state materials and promotes understanding of Sn4+ functions in biological systems, environments, and solid-state materials. [ABSTRACT FROM AUTHOR]

Optical eigenstates with a high quality (Q) factor provide substantial advantages for a broad spectrum of optical devices, particularly those demanding strong light–matter interactions. Recently, it has been demonstrated that ultrahigh- Q resonances can be realized in planar photonic structures by merging multiple bound states in the continuum (BICs) in the momentum space. Photonic lattices with thin-film geometry are known to support abundant TE-polarized and TM-polarized BICs. While prior research has explored the merging of TE-polarized BICs, this paper presents analytical and numerical results concerning the merging of TM-polarized BICs in laterally periodic one-dimensional photonic lattices. As the thickness of photonic lattices increases, TM-polarized accidental BICs descend along the dispersion curves and eventually merge at the upper edge of the second stop band. Employing coupled-mode analysis, we calculate the analytical merging thickness at which multiple TM-polarized BICs come together at the second-order Γ point. We confirm the merging of TM-polarized BICs through finite-element method simulations. Our results can be beneficial for achieving ultrahigh- Q resonances through the merging of BICs. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) piezoelectric nanomaterials have widely been studied recently due to their promise for various applications in technology. Investigation of vertical piezoelectricity will contribute to a deeper understanding of the intrinsic mechanism of piezoelectric effects in the 2D structures. In this paper, we report a first-principle study for the structural, electronic, piezoelectric, and transport properties of new-designed Janus WSi Z 3 H (Z = N, P, and As) monolayers. The structural stability of WSi Z 3 H is theoretically confirmed based on the energetic, phonon dispersion, and also elastic analyses. At the ground state, while WSiN 3 H is an indirect semiconductor, both WSiP 3 H and WSiAs 3 H are predicted to be direct semiconductors with smaller bandgaps. When the spin-orbit coupling effects are taken into account, a large valley spin splitting is observed at the K point of WSi Z 3 H materials. Interestingly, a giant Rashba spin splitting is found in WSiP 3 H and WSiAs 3 H with Rashba constant α R up to 770.91 meV Å. Additionally, our first-principles study indicates that Janus WSi Z 3 H monolayers are piezoelectric semiconductors with high out-of-plane piezoelectric coefficient | d 31 | , up to 0.15 pm/V, due to the broken mirror symmetry. Besides, with high electron mobilities and also possessing direct band gaps, WSiP 3 H and WSiAs 3 H monolayers are favorable for applications in optoelectronics. [ABSTRACT FROM AUTHOR]

Co-doping of phosphorus and boron elements into crystalline silicon quantum dot (c-Si QD) is an effective approach for enhancing the photoluminescence (PL) performance. In this paper, we report on the preparation of hydrogenated silicon nitride (SiNx:H) thin films embedded with phosphorus-boron co-doped c-Si QDs via plasma enhanced chemical vapor deposition route. Mixed dilution including hydrogen (H2) and argon (Ar) is applied in the in-situ deposition process for optimizing the deposition process. The P-B co-doped c-Si QD/SiNx:H thin films exhibit a wide range of PL spectra. The emission is greatly improved especially for the short-wavelength light when compared to the SiOx:H thin film containing P-B co-doped c-Si QDs. The effects of H2/Ar flow ratio on the structural and optical characteristics of thin films are systematically investigated through a series of characterizations. Experimental results show that various properties, such as crystallinity, QD size, optical band gap and doping concentrations, are effectively controlled by tuning H2/Ar flow ratio. Based on the red-shift of QCE-related PL peak, the successful P-B co-doping into Si QDs are verified. Finally, a comprehensive discussion has been made to analyze the influence of H2-Ar mixed dilution on the film growth and impurity doping in detail in this paper. [ABSTRACT FROM AUTHOR]

This paper reviews sintered silver (s-Ag) die-attach materials for wide band gap (WBG) semiconductor packaging. WBG devices that die-attach with s-Ag have attracted a lot of attention owing to their low energy loss and high temperature operation capabilities. For their practical operation, a reliability design should be established based on the failure of physics of the s-Ag die layer. This paper first focuses on the material characteristics of the s-Ag and tensile mechanical properties. Then, the s-Ag die-attach reliability is assessed with high-temperature storage, power cycling, and thermal shock tests. Each fracture mode was discussed by considering both the fracture surface analysis results and its mechanical properties. Finally, the effective reliability design parameters of the s-Ag die layer are introduced. [ABSTRACT FROM AUTHOR]

Context: The key factor in designing heat-resistant energetic materials is their thermal sensitivity. Further research and prediction of thermal sensitivity remains a great challenge for us. This study is based on first-principles calculations and establishes a theoretical model, which comprehensively considers band gap, density of states, and Young's modulus to obtain a empirical parameter Ψ. A quantitative relationship was established between the new parameter and the thermal decomposition temperature. The value of Ψ is calculated for 10 energetic materials and is found to have a strong correlation with the experimental thermal decomposition temperature. This further proves the reliability of our model. Specifically, the larger the value of Ψ, the higher the thermal decomposition temperature, and the more stable the energetic material will be. Therefore, to some extent, we can use the new parameter Ψ calculated by the model to predict thermal sensitivity. Methods: Based on first-principles, this paper used the Cambridge Serial Total Energy Package (CASTEP) module of Materials Studio (MS) for calculations. The Perdew-Burke-Ernzerhof (PBE) functionals in Generalized Gradient Approximation (GGA) method as well as the Grimme dispersion correction was used in this paper. [ABSTRACT FROM AUTHOR]

Microfluidic paper-based analytical devices modified with molecularly imprinted polymers (μPADs@MIPs) were developed for fluorescent detection of targeted thiols via in situ UV-induced formation of quantum dots (μPADs@MIPs@QDs). The selectivity enhancement by the MIP layer formed on the filter paper surface was demonstrated for the isolation of L-homocysteine from wine. Followed by the addition of metal precursors solution (Zn/Cd/Cu) and UV irradiation, fluorescent quantum dots were formed thus enabling quantitative detection of the thiol (serving as a QD capping agent). The effect of different semiconductors was investigated to achieve a lower band gap and higher fluorescence intensity. Increasing fluorescence intensity in the presence of thiol groups was obtained for the following precursors mixture composition: ZnCdCu/S > ZnCd/S > ZnCu/S > ZnS. The proposed method has a good relationship between the fluorescence intensity of ZnCdCu/S QDs and L-homocysteine in a linear range from 0.74 to 7.40 μM with a limit of detection (LOD) and quantification (LOQ) of 0.51 and 1.71 μM respectively. This method was applied for the determination of L-homocysteine in white wine with RSD under 6.37%. [Display omitted] • Microfluidic paper-based analytical devices modified with MIPs (μPADs@MIPs). • Selective isolation of L-homocysteine from wine. • UV- induced in situ formation of fluorescent clusters. [ABSTRACT FROM AUTHOR]

In this study, we reported the photoluminescence (PL) behaviour of a new intramolecular charge transfer (ICT) compound, ((E)-2-(((2-hydroxynaphthalen-1-yl)methylene)amino)benzoic acid, (HABA), which shows ICT solvent effect in aprotic solvents as confirmed by absorption and emission spectra. While in protic solvents including water and ethanol, the charge transfer (CT) band significantly reduces. Remarkable fluorescence enhancement in the blue region was also observed for HABA in polar protic solvents. We described such phenomena as “specific solvent effect”. It can be ascribed to the hydrogen bonding formation between HABA and protic solvents, which not only causes significant reduction in the rate of internal conversion but also elevates the energy gap. Density functional theory (DFT) calculations as well as the dynamics analysis were performed to further verify the existence of hydrogen bonding complexes. Stronger emission turn-on effect was observed on HABA solid film when it is treated with water and base solution. The stimuli-responsive fluorescence of HABA enables a new green printing technique that uses water/base as the ink, affording fluorescent handwritings highly distinct from the background. Thermoanalysis of the dye suggests the nice thermostability, which is highly desired for real-world printing in a wide temperature range. [ABSTRACT FROM AUTHOR]

Abstract This comment concerns the doubtful new auxiliary equation method (Khater method) included in the above paper. We prove by simple calculation that this method is wrong. The exact solutions of the proposed nonlinear equation obtained in the above paper are all wrong. Highlights • The new auxiliary equation method is called Khater method. • We prove by simple calculation that Khater method is wrong. • We show that the exact solutions obtained in the above paper are all wrong. [ABSTRACT FROM AUTHOR]

An epoxy-based metamaterial plate structure with local resonance is designed in this paper. The bandgap of the bending wave ranges from 36.46Hz to 110.55Hz. Through the optimization design of the oscillators in the plate structure, the starting bandgap moves to 19.79Hz, and the band gap width is 72Hz. The dispersion curve and frequency response function were calculated by finite element method (FEM). On this basis, the plane wave expansion method formula of the structural model was derived, and the equivalent model of spring-mass model was established. The results show that the calculation results of the three methods of the epoxide metamaterial plate structure were basically consistent, and the correctness of these methods was verified mutually. The methods derived in this paper bring great convenience and diversity to the application of plate structure. The article proposes a low-frequency wide bandgap thick plate structure model. [ABSTRACT FROM AUTHOR]

This paper introduces a structural design which has superior energy harvesting ability. The proposed structure is based on the ability of most periodic structures to prohibit elastic waves from propagating in a specific frequency range of the phonon band gap. By leading into acoustic black hole (ABH) units and utilizing the energy concentration characteristics of the ABH structure, the filtering effect can be made more significant. These two characteristics can produce significant strain and energy localization, which is conducive to energy harvesting. In this paper, we obtained ABH unit capable of producing broadband gaps by adjusting the geometric parameters of the ABH structure, and chose a cantilever as the research object for energy harvesting, by applying a piezoelectric patch on the unit located near the fixed end to gain a broader application in the actual situation. The results show that the beam combining the energy concentration characteristics of band gap and ABH structure has a significant improvement in energy harvesting efficiency. Optimization on the parameters of ABH unit shows that the band gap characteristic of the periodic ABH structure can further optimize the energy harvesting efficiency of practical energy harvesters, and opens up a new possibility of energy harvesting of ABH structure. [ABSTRACT FROM AUTHOR]

The research addresses the pressing need to understand wind conditions for optimal wind energy utilization, a crucial aspect of achieving global energy sustainability. While previous studies have focused on assessing wind energy potential and terrain roughness, gaps persist in understanding how wind and spatial conditions affect blade geometry. Therefore, this study aims to investigate the impact of local wind conditions on wind turbine blade geometry, integrating nonuniform wind inflow due to wind shear into the theoretical model. Through the paper, it explores blade design for varying inflow conditions and analyses the relationship between terrain type and blade designs. A novel approach to wind turbine blade design, utilizing a theoretical model that combines the local momentum theorem with insights from propeller vortex theory was adopted. Through the analysis, the authors demonstrate that variations in terrain significantly influence blade geometry, underscoring the necessity for tailored turbine designs based on local conditions. The findings reveal discrepancies in blade geometry across different turbine capacities and terrain types, offering novel insights into wind turbine performance optimization. By tailoring blade geometry to specific locations enhances resource utilization, offering insights for energy policymakers. The research provides validated methods for optimizing turbine geometric parameters, opening avenues for increased local investment in wind energy and promoting distributed energy development. Illustrated with wind plants examples, the paper concludes by outlining future research directions in this field. [ABSTRACT FROM AUTHOR]

Iron hydroxide (Fe(OH)3) nanoparticles have garnered considerable attention for their effectiveness in water treatment. This paper reviews recent studies on the photocatalytic degradation of phenol using Fe(OH)3, detailing the synthesis procedure, photocatalytic reaction conditions under UV‐C and catalyst amount optimization. Iron hydroxide was synthesized using a facile precipitation method, and the produced catalyst was thoroughly characterized using XRD, FTIR, UV‐DRS, DTA/TGA and SEM. Characterization results indicated that the catalyst exhibited very low crystallinity, a 1.84 eV band gap, and very small particle sizes. The study investigated the degradation performance of phenol for different amounts of iron hydroxide, ranging from 0.1 g to 1 g, and determined the optimum catalyst amount to be 0.7 g. The catalyst demonstrated a degradation efficiency for phenol exceeding 90 % at the end of a 180 minute photocatalytic reaction. The paper offers a comprehensive analysis of Fe(OH)3 as a photocatalyst for phenol degradation, highlighting its potential for future applications in water treatment. [ABSTRACT FROM AUTHOR]

Periodic structures are a type of metamaterial in which the physical properties depend not only on the details of the unit cell but also on how unit cells are arranged and interact with each other. In conventional engineering structures, each unit cell interacts with adjacent cells. Methods developed for vibrational and wave propagation analysis in periodic engineering structures consider only nearest-neighbor interactions. The dispersion curves of such systems, in which only adjacent cells interact, have been extensively studied. Metamaterial properties depend on the interactions of a unit cell with other cells. Further interactions, and specifically, interactions beyond the closest neighbors, imply a more complex band structure and wave behavior. In this paper, an example class of such structures, in which electrostatic forces are the driving force, has been investigated. In this paper, properties affecting these periodic structures, such as elastic forces, have been investigated. An attractive property of such structures is that the band structures of such metamaterials can be tuned by changing electric voltages. [ABSTRACT FROM AUTHOR]

In the present paper, we have conducted both theoretical and experimental investigations on thin films of lead sulfide (PbS). The structural and morphological properties of these films, which were prepared using the spray pyrolysis method, were analyzed utilizing X-ray diffraction (XRD) and scanning electron microscopy (SEM). Theoretical calculations were performed employing the first principles full potential linearized augmented plane wave (FP-LAPW) approach. The findings of this study reveal that the PbS film that was deposited is polycrystalline and possesses a rock-salt structure. The SEM image depicts a planar structure with dimensions ranging from 480 to 930 nm. The results obtained through energy dispersive spectroscopy (EDS) indicate high crystalline quality, and the film surface exhibits a rough texture and a dense morphology. In terms of its behavior, PbS acts as a semiconductor with a direct optical band gap situated at the L point of the Brillouin zone (BZ). The density of states on both sides of the band gap is primarily of s-p character. The ionic nature of PbS can be attributed to charge transfer. A substantial level of agreement has been observed between the experimental and theoretical results. Our ongoing research endeavors aim to explore biosensors and their various applications. The novelty of this work lies in the combined study of the structural and morphological properties of PbS films grown using the spray pyrolysis technique, employing both experimental and theoretical approaches. This paper describes a comprehensive approach to understanding bulk and thin-film PbS materials through theory and experimentation. [ABSTRACT FROM AUTHOR]

Context: In this paper, we systematically studied the effects of non-metallic element (B, C, N, O, F) doping and biaxial stretching on the photoelectric properties of ZrS2/ZrSe2 heterostructures by using the first-principles calculation method based on density functional theory. The results show that the p-type doping is realized by B, C, and N atom doping, and the n-type doping is realized by O and F atom doping. The doping of B and C atoms produces impurity energy levels in the band gap, which affects the conductivity of the heterostructure. The band gap of N and O atom–doped heterostructures increases under tensile strain, but it is still a direct band gap. The analysis of the optical properties of the heterostructures shows that the doping of non-metallic atoms can adjust the optical absorption rate and reflectivity of the heterostructures. Under the action of tensile strain, the optical properties of the doped heterostructures have changed significantly in the low-energy region. This article provides a theoretical basis for the future application of ZrS2/ZrSe2 heterostructures. Method: This paper uses the first-principles calculation method based on density functional theory. The PBE exchange-correlation functional based on generalized gradient approximation (GGA) is selected for the specific calculation, and the crystal structure is geometrically optimized by the ultrasoft pseudopotential method. It is verified that when the cutoff energy of the ZrS2/ZrSe2 heterostructure is 500 eV, the K-point grid is selected to be 10 × 10 × 2 with the lowest energy, so the cutoff energy is selected to be 500 eV. The K-point grid is selected to be 10 × 10 × 2. The convergence limits for structural optimization are as follows: the maximum force between atoms is 0.01 eV/Å, the convergence threshold of the maximum energy change is set to 10−9 eV/atom, and the convergence threshold of the maximum displacement is 0.001 Å. In order to avoid the influence of atomic periodic motion between different atomic layers, a vacuum layer of 20 Å is added in the vertical direction. Considering the interaction of vdW between the interfaces, the DFT-D2 method is used to verify. The optical properties were calculated by the random phase approximation method, and the K-point grid was selected as 12 × 12 × 2. [ABSTRACT FROM AUTHOR]

Accurate quantum efficiency measurement not only provides crucial information for the photovoltaic cell industry but also supports experiments aimed at directly detecting dark matter and elastic neutrino interactions. The dark matter direct searches paradigm has recently expanded to include particles with masses below 1 , MeV / c 2 , where the expected signal in an electron–recoil interaction is approximately in the eV range, just above the energy gap for silicon and germanium. A robust calibration method for ionization signals in this lower energy region is essential. This paper presents a method for measuring quantum efficiency and yield (q/E) in semiconductors using phonon-mediated calorimetry. The Neganov–Trofimov–Luke phonon amplification method in low-temperature semiconductor crystals has been employed to indirectly measure ionization down to single-electron accuracy. Specifically, at zero bias, the phonon readout directly quantifies the total energy deposited within the detector, independent of the ionization yield. This eliminates a significant source of systematic uncertainty in quantum efficiency estimates associated with total energy uncertainty. The paper includes results from an updated ionization efficiency measurement in a germanium detector. [ABSTRACT FROM AUTHOR]

Context: In this paper, the optimum coverage of 4.44% and the optimum adsorption sites were determined for the Be3N2 adsorption system of O atoms at different coverages based on density functional theory. The electronic and optical properties of the model were investigated by applying bending deformation to the model at these coverage and adsorption sites. Adsorption of O atoms disrupts the geometrical symmetry of Be3N2, resulting in orbital rehybridization and lowering its band gap. Bending deformation causes the band gap of the adsorbed O atom structure of Be3N2 to first increase and then decrease, resulting in the modulation of its band gap. With increasing bending deformation, the adsorbed system is redshifts, and the degree of redshift increases with increasing bending deformation. Methods: All calculations in this paper were performed using the first-principles-based CASTEP module of Materials Studio (MS). The generalized gradient approximation (GGA) plane-wave pseudopotential method and the Perdew-Burke-Ernzerhof (PBE) Perdew et al. Phys Rev Lett 77:3865, 1996 generalized functional were used in the geometry optimization and calculation process to calculate the exchange–correlation potential between electrons. The effect of coverage on the electronic and optical properties of the Be3N2-adsorbed O atom system was investigated by adsorbing different numbers of O atoms on a monolayer of Be3N2. The Be3N2 protocell contains two N atoms and three Be atoms with a space community of P6/MMM (No.191). The original cell was expanded 3 times along the direction of the base vectors a and b in the Be3N2 plane to create a 3 × 3 × 1 monolayer Be3N2 supercell system. A vacuum layer of 15 Å is set in the direction of the crystal plane of the vertical monolayer Be3N2 supercell to eliminate interactions between adjacent layers. In the overall energy convergence test of the Be3N2 supercell, the plane wave truncation energy was set to 500 eV, and the energy difference between the calculations given in the literature Reyes-Serrato et al. J Phys Chem Solids 59:743-6, 1998 using 550 eV was less than 0.01 eV, verifying the reliability of the data at a truncation energy of 500 eV. The Monkhorst–Pack special k-point sampling method Monkhorst et al. Phys Rev B 13:5188, 1976 was used in the structural calculations, and the grid was set to 3 × 3 × 1. The geometric optimization parameters are set as follows: the self-consistent field iteration convergence criterion is 2.0 × 10−6 eV, and the iterative accuracy convergence value is not less than 1.0 × 10−5 eV/atom for the total force of each atom and less than 0.03 eV/Å for all atomic forces. In addition the high-symmetry k-point path is taken as Γ(0,0,0) → M(0,0.5,0) → K(− 1/3,2/3,0) → Γ(0,0,0) Chen et al, AIP Adv 8:105105, 2018. [ABSTRACT FROM AUTHOR]

The flexible photodetector plays an important role in improving human medical health status. However, the narrow spectral detection range, poor stress stability, and non‐degradation of traditional flexible photodetectors greatly hinder the further development of wearable medical devices. In this paper, a novel flexible infrared photodetector is proposed for intelligent healthcare monitoring using high purity lead sulfide (PbS) nanoparticles on paper‐based flexible substrate synthesized by hydrothermal method and physical friction. The excellent performance of the detector is attributed to the 1.01 eV band gap and six‐arm stellate dendritic structure of PdS, a good combination between PbS and paper substrate via physical friction. As a result, our photodetector demonstrates wide‐spectrum detection capabilities from 365 to 1550 nm. The photodetector at 980 nm (50.4 μW cm−2) shows responsivity of 6.45 mA W−1, detectivity of 6.4 × 1010 Jones, response recovery time of 0.36 s/0.41 s, with good mechanical stability. By comparison, our detector has a wider detection range, better weak signal detection performance, and shorter response time than the performance of the former paper‐based detector. Furthermore, the paper‐based PbS photodetector as a dual‐wavelength photoplethysmography sensor is applied to analyze the oxygen saturation and develop an intelligent bandage to monitor wound healing. This paper‐based PbS photodetector has tremendous potential in the field of wearable medical devices and intelligent medical applications are expected. [ABSTRACT FROM AUTHOR]

In order to achieve low frequency vibration and noise reduction, researchers have found and explored many types of metamaterial structures. Based on this, an innovative multiphase metamaterial structure composed of hard materials and soft materials is proposed in this paper. According to Bloch's theorem, the band gap characteristics of the proposed structure are calculated using the finite element method, and the formation mechanism of the band gap is analyzed. In addition, the effects of the stiffness and density of the two materials on the band gap are studied in detail. Then, the phase velocity, group velocity and wave propagation direction are calculated according to a certain frequency of the specific dispersion curve, and the important information of wave propagation in the structure is obtained. Finally, according to the transmission characteristics of vibration in a finite periodic structure, it is verified that the existence of band gap can inhibit the vibration transmission, and it is further clarified that the proposed structure has a good performance in the design of low-frequency band gaps with large amplitude. [ABSTRACT FROM AUTHOR]

Meeting the growing demand for robust, earth-abundant and noble-metal-free photocatalysts for practical hydrogen-evolution reaction systems is crucial. Herein, cation modified perovskite niobates, Na0.5Sr0.5M0.25Nb0.75O3 (M = Cr, Mn, Fe, Co), are synthesized using a simple heterovalent coupled substitution strategy via solid-state reactions. The Cr compound as a single semiconductor system exhibits a photocatalytic hydrogen evolution rate of 188 μmol h−1 g−1, which significantly surpasses the performance of many contemporary catalysts that rely on the use of noble metal cocatalysts. Apparent quantum efficiencies (AQEs) of Cr, Mn, Fe and Co containing compounds are 2.24, 0.55, 0.65 and 0.74%, respectively. The photophysical properties like tuned band gap, suitable energy level positioning, charge carrier density, photostability of the materials and charge transfer resistance that are responsible for efficient spatial charge separation and charge transfer dynamics impacting the hydrogen evolution are investigated. This paper discusses the role of cation modification and its effects on the photophysical properties and hydrogen evolution activity of the perovskite niobates under noble-metal free conditions. These nonprecious noble-metal-free perovskite niobates furnish a new perspective for the future design of photocatalysts for efficient photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the Bloch bands and develop a linear response theory for nonlinear systems, where the interplay between topological parameters and nonlinearity leads to new band structures. The nonlinear system under consideration is described by the Qi–Wu–Zhang model with Kerr-type nonlinearity, which can be treated as a nonlinear version of Chern insulator. We explore the eigenenergies of the Hamiltonian and discuss its Bloch band structures as well as the condition of gap closing. A cone structure in the ground Bloch band and tubed structure in the excited Bloch band is found. We also numerically calculate the linear response of the nonlinear Chern insulator to external fields, finding that these new band structures break the condition of adiabatic evolution and make the linear response not quantized. This feature of response can be understood by examining the dynamics of the nonlinear system. [ABSTRACT FROM AUTHOR]

Yttrium oxide (Y2O3)$( {{{\mathrm{Y}}}_2{{\mathrm{O}}}_3} )$ has the potential to be used as a host material for creating polycrystalline transparent ceramics (PTCs). This paper presents an experimental study on opto‐electrical properties of Y2O3${{\mathrm{Y}}}_2{{\mathrm{O}}}_3$ using zirconium oxide (ZrO2)$( {{\mathrm{ZrO}}_2} )$ and lanthanum oxide (La2O3)$({\mathrm{La}}_2{{\mathrm{O}}}_3)$ as sintering aids via the co‐precipitation technique. The sintering aids improve the properties, sintering process, and lower the sintering temperature. Five different compositions of Y2O3(((Y1−xZr0.02Lax)2O3),wherex=0,3,6,and9at.%)${{\mathrm{Y}}}_2{{\mathrm{O}}}_3\ ( {({{( {{{\mathrm{Y}}}_{1 - x}{\mathrm{Zr}}_{0.02}{\mathrm{La}}_x} )}}_2{{\mathrm{O}}}_3} ),{\mathrm{\ where\ }}x = 0,\ 3,\ 6,{\mathrm{\ and\ }}9{\mathrm{\ at}}.{\mathrm{\% }})$ were synthesized and they were then used to analyze for their structural, morphological, physio‐chemical, and electrical characteristics. For the system studied, the addition of ZrO2${\mathrm{ZrO}}_2$ and La2O3${\mathrm{La}}_2{{\mathrm{O}}}_3$ does not change the phase of pure Y2O3${{\mathrm{Y}}}_2{{\mathrm{O}}}_3$, but an increase in the crystal and grain size from 31.2$31.2$ to 42.5nm$42.5{\mathrm{\ nm}}$ and 10.2 µm to 16.4 µm was noticed. The thermal characterization over thermogravimetric analysis/differential thermal calorimetry (TGA/DSC) determines the temperature at which pure Y2O3${{\mathrm{Y}}}_2{{\mathrm{O}}}_3$ undergoes a phase transition, specifically over 700°C. A reduction in the band gap due to strain induced by the dopant resulted in a decrease in energy from 5.54$5.54$ to 4.8eV$4.8{\mathrm{\ eV}}$. The dielectric constant of Y2O3${{\mathrm{Y}}}_2{{\mathrm{O}}}_3$ doped with 9at.%La$9{\mathrm{\ at}}.{\mathrm{\% \ La}}$ exhibits a significant increase of ∼50%${\sim}50\%$. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO2) is one of the important semiconductors used in the application of solar cells because of its chemical–mechanical stability and wide band gap. These properties are very important for the performance development and photoanode optimization of a dye‐sensitized solar cell (DSSC). However, the low conduction band value of SnO2 reduces the photovoltaic efficiency, which limits the application of DSSC. Therefore, the doping strategy was used to increase the sensitivity to the visible light spectrum and change the light absorption properties of SnO2. In this paper, pure SnO2, Ag/SnO2, Pt/SnO2, and Pt/Ag/SnO2 nanoparticles were synthesized at the nanoscale by a simple chemical sol–gel method. To characterize the structure, morphological/chemical properties, optical properties, and surface properties of the synthesized SnO2 nanoparticles, X‐Ray Diffraction (XRD), ultraviolet–visible, Brunauer–Emmett–Teller, Scanning Electron Microscopy (SEM)/Energy Dispersive X‐Ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), and particle size analysis were respectively used. XRD results showed that the crystal sizes varied between 8.8 and 12.2 nm depending on the doping. Doping processes resulted in reductions in particle sizes. Optical studies resulted in decreases in the band gap with the doping process. The conclusions obtained have shown that Ag doping, and Pt–Ag co‐doping can be promising for use as photoanode materials in semiconductor technology and especially in DSSC applications. [ABSTRACT FROM AUTHOR]

The electronic and photocatalytic properties of a type-II ZnS/HfS 2 heterojunction are comprehensively analyzed through first-principles calculations in this paper. By calculating the binding energy and phonon spectrum of five potential stacking patterns, the stable structure of the ZnS/HfS 2 heterojunction is determined. The electronic structure calculations indicate that the heterojunction has a type-II alignment with a 1.26 eV band gap. The heterojunction exhibits high carrier mobilities (4387.36 and 9561.39 cm2V–1S−1 for X and Y directions). The photocatalytic water splitting process of the heterojunction can be explained by the direct Z-scheme mechanism. The built-in electric field enables rapid recombination of electron-hole pairs at CBM and VBM, while the hydrogen evolution reaction and oxygen evolution reaction can separately be achieved at the ZnS layer and HfS 2 layer to complete the overall water splitting. The free energy analysis indicates that the ZnS/HfS 2 heterojunction has high activity for overall water splitting under illumination. Moreover, the calculated solar-to-hydrogen efficiency of the heterojunction reaches 30%, ensuring its photocatalytic performance. Remarkably, the type-II alignment is maintained and the catalytic performance can be further improved under biaxial strain because of the enhanced optical absorption in visible light and the reduced band gap. This work reveals that ZnS/HfS 2 heterojunction is a potentially novel photocatalytic material for efficient overall water splitting. [Display omitted] • Proposed novel type-II ZnS/HfS 2 heterojunction with 1.26 eV band gap. • Achieves overall water splitting via direct Z-scheme mechanism. • High carrier mobility and 30% solar-to-hydrogen efficiency. • Enhanced catalytic performance under biaxial strain. [ABSTRACT FROM AUTHOR]

This paper examines the influence of building characteristics, occupant demographics and behaviour on gas and electricity consumption, differentiating between family groups; homes with children; homes with elderly; and homes without either. Both regression and Lasso regression analyses are used to analyse data from a 2019 UK-based survey of 4358homes (n = 1576 with children, n = 436 with elderly, n = 2330 without either). Three models (building, occupants, behaviour) were tested against electricity and gas consumption for each group. Results indicated that homes without children or elderly consumed the least energy. Property Type emerged as the strongest predictor in the Building Model (except for homes with elderly), while Current Energy Efficiency was less significant, particularly for homes with elderly occupants. Homeownership and number of occupants were the most influential factors in the Occupants Model, though this pattern did not hold for homes with elderly. Many occupant and behaviour variables are often considered 'unregulated energy' in calculations such as SAP and are thus typically disregarded. However, this study found these variables to be significant, especially as national standards improve. The findings suggest that incorporating occupant behaviour into energy modelling could help reduce the energy performance gap. [ABSTRACT FROM AUTHOR]

With the rapid development of flexible displays and wearable electronics, there are a substantial demand for colorless transparent polyimide (CPI) films with different properties. Traditional trial‐and‐error experimental methods are time‐consuming and costly, and density functional theory based prediction of HOMO‐LUMO gap energy also takes time and is prone to varying degrees of error. Inspired by machine learning (ML) applications in molecular and materials science, this paper proposed a data‐driven ML strategy to study the correlation between microscopic molecular mechanisms and macroscopic optical properties. Based on varying degrees of impact of various molecular features on the cutoff wavelength (λcutoff), the ML algorithm is first used to quickly and accurately predict the λcutoff of CPI. Several new CPI films are then designed and prepared based on the key molecular features, and the predicted values of their λcutoff are effectively verified within the experimental error range. The interpretability provided by the model allows to establish correlations between the nine key descriptors identified and their physicochemical meanings. The contributions are also analyzed to the transparency of polyimide films, thereby giving insight into the molecular mechanisms underlying transparency modulation for CPIs. [ABSTRACT FROM AUTHOR]

Tunneling field-effect transistors (TFETs) based on 2D materials have emerged as promising candidates for low-power devices. However, many TFETs utilizing 2D materials suffer from the limitation of low ON current. Black phosphorene, a 2D material exhibiting a high ON current and also an appropriate band gap, is known as a notable candidate. This paper investigates simulation results of armchair/zigzag phosphorene nanoribbon tunneling field-effect transistors (APNR-TFET/ZPNR-TFET). Our approach relies on the combination of density functional-based tight binding with the nonequilibrium Green’s function. Results encompass energy band structure, I–V characteristics, on/off current ratio, Power-Delay Product (PDP), delay time and cutoff frequency. It is shown that ZPNR-TFETs possess a higher Ion/Ioff ratio, PDP and intrinsic gain compared to APNR-TFETs. Hence, the ZPNR-TFET is better suited for digital applications. Due to the increased gm in APNR-TFET, this structure exhibits a higher cutoff frequency, resulting in enhanced performance in analog applications. [ABSTRACT FROM AUTHOR]

Fluorophlogopite is a well-known fluorosilicate glass-ceramic derivative known for its bioactivity, machinability and optimal mechanical properties. There is limited information regarding its antibacterial and biocompatible properties. This research paper presents the synthesis and characterization of a novel Boron-doped Fluorphlogopite [KMg 3 (Al 0.5 B 0.5)Si 3 O 10 F 2 ] aiming to improve its antibacterial properties intended for anticariogenic applications. The combustion synthesis method was employed, with oxalyl dihydrazide (ODH) (C 2 H 6 N 4 O 2) serving as the fuel. X-ray Diffraction (XRD) analyses unveiled a monoclinic crystal system, showcasing a P2 1 space group, and an average crystallite size of approximately 28 nm. Morphological scrutiny divulged clustered, irregularly shaped, cluster-like structures. The energy gap was determined to be around 4.97 ± 0.0062 eV. Fourier-Transform Infrared (FTIR) spectroscopy depicted the presence of characteristic bonds. BET analysis indicated the presence of a large surface area and porous structure (mesopores), which may contribute to lower MIC and MBC values, enhancing antibacterial effectiveness. The antibacterial activity, evaluated via agar well diffusion, yielded an 8 mm zone of inhibition. Furthermore, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) against S mutans were determined to be 2 mg/ml and 16 mg/ml, respectively. The biocompatibility of the synthesized KMg 3 (Al 0.5 B 0.5)Si 3 O 10 F 2 was assessed through the MTT assay, indicating non-toxic behavior at a concentration of 12 μg/ml with 98 % cell viability, while showing moderate toxicity with 61 % viable cells at its highest concentration of 200 μg/ml. [ABSTRACT FROM AUTHOR]

BiOBr with different preferred growth orientation facets would show a different photocatalytic performance. When decorated in situ with metallic Bi nanoparticles, Bi/BiOBr would commonly display an enhanced photocatalytic performance. In this paper, the BiOBr nanoplates with preferred growth orientation (102) facet and (110) facet were first synthesized using a hydrothermal method. Then, some metallic Bi nanoparticles were modified in situ onto the (110)BiOBr nanoplates, which was expected to show a much more enhanced photocatalytic performance. All samples were characterized using XRD, FE-SEM, TEM, N2 adsorption–desorption, UV–vis and XPS. FE-SEM and TEM images showed that the grain size of the metallic Bi particles was about 5 nm to 10 nm. UV–vis spectra showed that, after some metallic Bi nanoparticles were modified on (110)BiOBr nanoplates, the light absorbance in the visible light region at 400–700 nm became stronger and their optical band gap became larger. N2 adsorption–desorption tests showed that the Bi(x)/(110)BiOBr nanosheets possessed larger specific surface areas than that of the (102)BiOBr and (110)BiOBr nanoplates. The XPS results showed that Bi(x)/(110)BiOBr contained more oxygen vacancies and a more negative value of the conduction band minimum. The photocatalytic performance of (102)BiOBr, (110)BiOBr and Bi(x)/(110)BiOBr were tested in the photocatalytic degradation of rhodamine B under visible light irradiation for 2 h; their photocatalytic efficiency was 45%, 75% and 80%, respectively. In comparison to (102)BiOBr, (110)BiOBr exhibited much higher photocatalytic activity, while for Bi(x)/(110)BiOBr, despite the surface Plasmon resonance effect, a larger specific surface area and more oxygen vacancies, the enhancement of the efficiency was limited, which might have resulted from the larger optical band gap. [ABSTRACT FROM AUTHOR]

Black phosphorus is a highly interesting two-dimensional material with a tunable band gap, ultra-high carrier mobility, and excellent optoelectronic properties. Its van der Waals spacing creates conditions for the entry of foreign substances, and various properties of BP can be effectively regulated by intercalation. In this paper, organic ammonium salts (CTAB, hexadecyl trimethyl ammonium bromide and TBAB, Tetrabutyl ammonium bromide) were chosen as the intercalated guests and BP bulk crystals were used as the intercalation hosts, and the effects of intercalation on the Raman as well as photoluminescence (PL) properties of BP were mainly investigated. The results show that the intercalation of organic ions leads to an overall redshift of the Raman modes corresponding to the three phonon vibrational modes of Ag1, B2g and Ag2. In particular, the PL emission spectrum of the intercalated BP bulk exhibits a continuous spectrum bridging the peaks of the bilayer (1.35 eV), monolayer (1.7 eV) and the defect states. The prepared intercalation products also possess good stability under atmospheric conditions. Our study provides an idea for modulating the electronic and optical properties of bulk 2D materials, which has potential applications in the field of optoelectronics of crystalline materials. [ABSTRACT FROM AUTHOR]

Context: Myocardial infarction is one of the major health challenges. It is of great significance to develop potential delivery carriers for new anti-myocardial infarction drugs. In this paper, based on first-principles calculations, monolayer WS2 with excellent photoelectric properties was verified as a carrier for the anti-myocardial infarction drug amiodarone (AMD). Studies have shown that the WS2-adsorbed AMD system (WS2@AMD) maintains structural stability and produces an adsorption energy of—2.12 eV. Mulliken charge analysis shows that electrons are transferred from WS2 atoms to AMD atoms. Among them, C, N and O obtained the maximum values of 0.51,0.37 and 0.56 e electrons, respectively, while H and I lost the maximum values of 0.32 and 0.24 e electrons, respectively. The optical response of WS2 adsorbed AMD system is similar to that of WS2. The light absorption coefficients of the two materials in the near ultraviolet region and the visible region can reach the order of 105 cm−1 and 104 cm−1, and the strain makes the light absorption peak red-shifted. The feasibility of temperature-controlled release mechanism of WS2 as AMD carrier was discussed. This theoretical work helps to improve the performance of two-dimensional nanomaterials and make them better as drug delivery carriers to improve the therapeutic effect of myocardial infarction. These results indicate that the WS2 monolayer has potential applications in the development of drug delivery carriers. Methods: In this study, based on first-principles calculations, the CASTEP simulation software package was used to study the structure and properties of materials. The interaction between electrons and ions is considered by using Ultrasoft pseudopotentials. In order to eliminate the spurious interaction between adjacent structures caused by periodic calculations, a vacuum space no less than 18 Å is placed in the vertical direction if necessary. Different functions may produce different density functional calculation results. Due to the low sensitivity of the crystal structure to the calculation details, the PBE functional under the generalized gradient approximation (GGA) was initially used for structural optimization, and the energy cutoff value was set to 500 eV. Grimme 's dispersion correction was used to make the results more accurate. The Brillouin zone (BZ) is sampled by a 7 × 7 × 1 K-point grid to ensure the reliability of the original lattice calculation. The lattice vector and atomic coordinates are relaxed, and the tolerance of each atom is less than 0.01 eV/Å. The energy tolerance at the atomic position is less than 10–7 eV/atom. When calculating the band gap, the HSE06 hybrid functional is used to modify the optimized structure of the PBE functional to obtain more accurate results. Spin-polarized DFT calculations were performed to calculate the electronic structure. [ABSTRACT FROM AUTHOR]

Exploration of compounds featuring multiple anions beyond the single-oxide ion, such as oxyhalides and oxyhydrides, offers an avenue for developing materials with the prospect of novel functionality. In this paper, we present the results for a mixed anion layered material, ScHX2 (X: Br, I) based on density functional theory. The result predicted the ScHX2 (X: Br, I) monolayers to be stable and semiconducting. Notably, the electronic and mechanical properties of the ScHX2 monolayers are comparable to well-established 2D materials like graphene and MoS2, rendering them highly suitable for electronic devices. Additionally, these monolayers exhibit an ability to adjust their band gaps and band edges in response to strain and substrate engineering, thereby influencing their photocatalytic applications. [ABSTRACT FROM AUTHOR]

This paper presents a novel locally resonant metamaterial structure and proposes a method to analyze its elastic wave dispersion properties. The structure is conceived as a multiple beam system with parallel beams transversely interconnected by periodic arrays of small resonators, each consisting of a spring-mass-spring subsystem in parallel with a couple of springs. Inserting the resonators between the beams, instead of attaching them as external appendages like in some alternative examples of locally resonant beams in the literature, makes the structure appealing for practical realization and use; furthermore, hosting several arrays of resonators gives the possibility to open multiple band gaps. The proposed method is a homogenization approach for flexural wave dispersion analysis, which removes the equations for the resonators from the set governing the dynamics of the system and reverts the original structure to an equivalent one featuring a tri-diagonal effective mass matrix with frequency dependent terms. The advantage of the homogenization approach is twofold: (1) it demonstrates that the band gaps arise in the frequency ranges where the effective mass matrix is negative definite, generalizing the well-established concept of band gaps attributable to negative mass effects in single locally resonant beams; (2) it provides dispersion curves and band gaps very efficiently, and the band gaps are identified upon calculating the eigenvalues of the tri-diagonal effective mass matrix. Analytical expressions of the band gap edges are obtained for the baseline case of a double beam system, to be readily used for design. Additionally, the exact transfer matrix method in conjunction with the Bloch theorem is formulated as alternative to the homogenization approach for wave dispersion analysis. Finally, the proposed concept of locally resonant structure and pertinent homogenization approach are validated by calculating the transmittance properties of the corresponding finite structure, via the standard finite element method. [ABSTRACT FROM AUTHOR]

In the present work, Al-doped (0, 1, 2 and 3%) ZnO nanoparticles (NPs) are synthesised by green combustion method (GCM) using Terminalia Catappa seeds (TCS) extract as a novel fuel. For the synthesis Zinc nitrate and Aluminum nitrate are used as precursor and dopant respectively. The synthesised NPs are characterised by XRD, FTIR, UV-vi and impedance spectroscopy. The XRD analysis shows decrease in crystallite size varies between 40 to 26 nm as dopant increases. The FTIR spectrum reaffirms the formation of Zn-O bonding structure at 454.28 cm−1. UV-Vi spectroscopic studies show the optical band gap of 3.63, 3.53, 3.22 and 3.19 eV for Al doped (0, 1, 2 and 3%) ZnO NPs. Thermal analysis for the synthesised Al-doped (0, 1, 2 and 3%) ZnO nanoparticles are analysed using TGA/DTA studies. The Electrical characteristics are studied at various temperatures (50 to 350°C) by varying frequency (10 Hz to 8 MHz). In low frequency regions, dielectric constant and dielectric loss increases with rise in temperature. The constant AC conductivity is observed in lower frequencies and increases for higher frequencies for all doped ZnO NPs. ZnO NPs prepared with 2% of doping exhibit improved structural and electrical properties. Hence these ZnO NPs may be used as sensing material for vibration sensor. Highlights: This paper focus on green synthesis of undoped and Al-doped ZnO nanoparticles by combustion method. ZnO nanoparticles are synthesised using zinc nitrate precursor, Aluminium nitrate as dopant and Terminalia catappa seed extract as fuel. Effect of Al (0, 1,2 and 3%) doping on microstructural, optical, thermal and electrical properties of ZnO nanoparticles are investigated. The green synthesised doped and undoped ZnO nanoparticles exhibit hexagonal wruzite structure with high crystallinity. The FTIR spectrum reaffirms the formation of Zn-O bonding structure at 454.28 cm-1 The optical band gap is found to be 3.63, 3.53, 3.22 and 3.19 eV for 0, 1,2 and 3% of Al doped ZnO nanoparticles respectively. AC conductivity of ZnO nanoparticles is found to be increased with 2% of Al doped ZnO nanoparticles. Result shows an improved structural, optical and electrical performance for 2% Al doped ZnO nanoparticles and hence these nanoparticles are suitable material for sensors, organic light emitting diodes and liquid crystal displays. [ABSTRACT FROM AUTHOR]

In this paper, based on the framework of the supplementary variable method, we present two classes of high-order, linearized, structure-preserving algorithms for simulating the regularized long-wave equation. The suggested schemes are as accurate and efficient as the recently proposed schemes in Jiang et al. (2022) [20] , but share the nice features in two folds: (i) the first type of schemes conserves the original energy conservation, as opposed to a modified quadratic energy in [20] ; (ii) the second type of schemes fills the gap of [20] by constructing high-order linear algorithms that preserve both two invariants of mass and momentum. We discretize the SVM systems by employing the algebraically stable Runge-Kutta method together with the prediction-correction technique in time and the Fourier pseudo-spectral method in space. The implementation benefits from solving the optimization problems subject to PDE constraints. Numerical examples and some comparisons are provided to show the effectiveness, accuracy and performance of the proposed schemes. [ABSTRACT FROM AUTHOR]

The primary goal of this paper is to study a few advantages of bulk nanoparticles of Cu-doped SnO2 using the solid-state reaction method. Many innovative methods were employed to evaluate the special tuning of the bandgap and other structural and morphological properties of the material. X-ray diffractometer (XRD) confirmed that tin oxide has a rutile-type tetragonal-shaped structure with space group P42 / mnm. The average crystallite size was calculated which was found to increase from 53 to 80 nm by increasing the Cu-doping from x = 0 to x = 0.30. SEM images specified that nanoparticles are inhomogeneous and densely close to each other and the average particle size was found to be in the range of ~225–430 nm. Transmission electron microscopy (TEM) images showed the grains present in a few cubic and spherical shapes and grain size was increased (~20–90 nm) with doping of copper in the SnO2 lattice. UV–Vis spectroscopy showed that the band gap increased from 3.531 to 3.701 eV for pure SnO2 and Cu-doped SnO2, respectively. XPS identified the electronic state of Sn as well as Cu atoms as 4 + and 2 + , respectively. Raman spectroscopy showed that only three vibrational modes, i.e., A1g, B2g and doubly degenerate Eg, exist in a sample. [ABSTRACT FROM AUTHOR]

Triethylamine (TEA) is a mephitic volatile organic compound, which has huge damage to human body. Therefore, the development of gas sensitive materials for the effective detection of TEA has important application value. In this paper, In 2 O 3 , ErVO 4 and In 2 O 3 /ErVO 4 composite samples were successfully synthesized by hydrothermal method. The In 2 O 3 /ErVO 4 composite of In 2 O 3 and ErVO 4 has a spherical structure with a rough surface, and forms a variety of porous structures, which effectively increases the specific surface area of the composite (58.9551m2/g), thereby improving the gas sensitivity to TEA. In 2 O 3 /ErVO 4 composites can achieve a higher response to 100 ppm TEA (S = 54.73), have a lower optimal operating temperature (250 °C) compared with In 2 O 3 pure samples, and have a faster recovery time (52 s) compared with ErVO 4 pure samples. In addition, In 2 O 3 /ErVO 4 sensors also achieve good selectivity, excellent moisture resistance, long-term stability. The microstructure of the sample was significantly changed by ErVO 4 recombination. These alterations include an increase in specific surface area, a decrease in particle size, an increase in the utilization of the sensitive body, an increase in the proportion of vacancy oxygen, a decrease in the optical band gap, and an increase in electron transport efficiency. These results show that the combination of ErVO 4 and In 2 O 3 to construct heterojunction can achieve excellent sensor for TEA gas detection. [ABSTRACT FROM AUTHOR]

In this paper, a NiAl-LDH with the characteristic structure of a hydrotalc-like compound was applied as a carrier in a two-step hydrothermal process, and a MnCdS/In2S3/NiAl-LDH composite material was successfully prepared by loading MnCdS and In2S3 on the flower spherical-like surface of NiAl-LDH. The combination of NiAl-LDH with In2S3 and MnCdS made the band gap smaller and the light absorption range larger, thus increasing the utilization rate of light. 50% MnCdS/In2S3/NiAl-LDH composites had the best photoinduced charge separation and highest surface enrichment of photogenerated electrons. In the degradation experiment of crystal violet (CV), 50% MnCdS/In2S3/NiAl-LDH composites showed superior photocatalytic degradation efficiency (>98.5%) under full spectrum light. Furthermore, the applicability and universality of photocatalysts were studied by observing the degradation of CV by MnCdS/In2S3/NiAl-LDH composites under different conditions. In addition, the composites showed excellent hydrogen production capacity in the photolysis of water, in which hydrogen production within 8 hours was about 7661.51 μmol g−1. By combining the results of active species capture experiments, density functional theory (DFT) calculations and photoelectrochemical experiments, the possible mechanism of double S-scheme heterojunction photocatalysis among NiAl-LDH, In2S3 and MnCdS was inferred, which is one of the main reasons for the enhancement of photocatalytic activity. [ABSTRACT FROM AUTHOR]

This paper presents a simulation of the structural and optoelectronic properties of Scandium Arsenide (ScAs) and Aluminum Arsenide (AlAs) compounds. Theoretical modeling was performed using ab initio first-principles calculations, specifically the density functional theory (DFT), and the Mindlab numerical software. The software used two methods: the full-potential muffin-tin orbital method (FP-LMTO) and the full-potential plane-wave method (FP-LAPW). These two methods are employed to solve the Schrödinger equation. The exchange correlation effects have been computed using two different approximations: the generalized gradient approximation (GGA) and the local density approximation (LDA). Our findings indicate that the zinc blende structure (B3) is the stable phase, while the Wurtzite phase (B4) is metastable for the AlAs compound. On the other hand, the ScAs compound crystallizes in the NaCl phase (B1). The AlAs compounds undergo three phase transitions: B3→B4, B3→B2 and B3→B1. In contrast, ScAs does not undergo any transition. The obtained results for equilibrium energies, lattice parameters and gap energies are in closer agreement with the experimental and theoretical data. The AlAs compound exhibits a semiconducting character, while ScAs exhibits a semi-metallic character. Additionally, the refractive index of these two compounds is similar to that of silicon, which is crucial for their application in photovoltaic cells. [ABSTRACT FROM AUTHOR]

Atom doping is widely present in graphene and silicene materials, which can effectively regulate the electrical properties of nanostructures. In this paper, the effects of doping carbon atoms at different positions on the geometric structure and electrical properties of bilayer zigzag silicene nanoribbons (ZSiNRs) with different widths were studied by self-consistent charge density functional tight-binding (SCC-DFTB) method. Carbon doping in silicene nanoribbons induces a local reconstruction, amplifies surface warpage, and boosts interlayer interactions. The width of the nanoribbons and the position and concentration of the doped carbon atoms significantly affect the stability of the bilayer silicene nanoribbons, which can effectively regulate its band gap. Especially when carbon atoms are doped at the edge, the width of the band gap can be effectively increased. Different doping positions and concentrations can cause nanoribbons to exhibit three properties: metallic, semi-metallic, and semiconducting. The doping position and concentration of carbon atoms significantly affect the charge transfer of silicene nanoribbons. In general, the charge is always transferred from silicon atoms to carbon atoms. [ABSTRACT FROM AUTHOR]

To effectively reduce vibration, a metamaterial beam with carbon fiber-reinforced polymer (CFRP) is proposed. The dispersion curves are calculated by the transfer matrix method (TM). The frequency response is investigated by the spectral element method (SEM). Displacement fields at different representative frequencies are displayed by the finite element method (FEM). The effects of the geometry, material parameters, and cross-ply angle of CFRP on the band gap are considered numerically, three types of beams are discussed and compared. From the results, it was found that the cross-ply angle and length of CFRP have significant influence on the band gaps. The frequency and width of the band gaps are different when the CFRP layers are imparity. Finally, a CFRP beam with ten periods was fabricated and the experiment was carried out to test transmission characteristics. Although the number of periods is only ten, it was found that the experimental results agree well with the numerical results in the low-frequency range. The results obtained in the paper can provide some useful reference for understanding and optimization of the design for metamaterial beam with wide band gaps, lightweight and high strength. [ABSTRACT FROM AUTHOR]

As a layered material with single/multi-atom thickness, two-dimensional transition metal sulfide WS2 has attracted extensive attention in the field of science for its excellent physical, chemical, optical, and electrical properties. The photoelectric properties of WS2 are even more promising than graphene. However, there are many existing preparation methods for WS2, but few reports on its direct growth on tungsten films. Therefore, this paper studies its preparation method and proposes an innovative two-dimensional material preparation method to grow large-sized WS2 with higher quality on metal film. In this experiment, it was found that the reaction temperature could regulate the growth direction of WS2. When the temperature was below 950 °C, the film showed horizontal growth, while when the temperature was above 1000 °C, the film showed vertical growth. At the same time, through Raman and band gap measurements, it is found that the different thicknesses of precursor film will lead to a difference in the number of layers of WS2. The number of layers of WS2 can be controlled by adjusting the thickness of the precursor. [ABSTRACT FROM AUTHOR]