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We demonstrate the change of the sign from negative to positive of the self-powered photovoltaic photocurrent in core–shell n-InGaN/p-GaN nanowire heterojunctions within the visible to UV wavelength range. Such dual-polarity photodetectors are of broad interest to provide extended functionalities for optoelectronic devices, starting with dual-wavelength photodetectors. The physics of the photocurrent sign reversal is understood by a well-balanced selective absorption and photocarrier generation, photocarrier transfer, and thermal excitation paths in the core–shell n-InGaN/p-GaN nanowire functional absorber with different bandgap energies and opposite inner- and surface energy band bendings. The basic dual-wavelength photodetector operation parameters are given. [ABSTRACT FROM AUTHOR]

The use of semiconductor nanocrystals in scalable quantum technologies requires characterization of the exciton coherence dynamics in an ensemble of electronically isolated crystals in which system–bath interactions are nevertheless strong. In this communication, we identify signatures of Fano-like interference between excitons and photocarriers in the coherent two-dimensional photoluminescence excitation spectral lineshapes of mixed lead-halide perovskite nanocrystals in dilute solution. Specifically, by tuning the femtosecond-pulse spectrum, we show such interference in an intermediate coupling regime, which is evident in the coherent lineshape when simultaneously exciting the exciton and the free-carrier band at higher energy. We conclude that this interference is an intrinsic effect that will be consequential in the quantum dynamics of the system and will thus dictate decoherence dynamics, with consequences in their application in quantum technologies. [ABSTRACT FROM AUTHOR]

Transition-edge sensors (TESs) have the potential to perform electron spectroscopic measurements with far greater measurement rates and efficiencies than can be achieved using existing electron spectrometers. Existing spectrometers filter electrons by energy before detecting a narrow energy band at a time, discarding the vast majority of electrons available for measurement. In contrast, TESs have intrinsic energy sensitivity and so do not require prior filtering to perform energy-resolved measurements. Despite this fundamental advantage, TES electron spectroscopy has not, to our knowledge, previously been reported in the literature. We present the results of a set of proof-of-principle experiments demonstrating TES electron spectroscopy experiments using Mo/Au TESs repurposed for electron calorimetry. Using these detectors, we successfully measured the electron spectrum generated by an electron beam striking a graphite target with energies between 750 and 2000 eV, at a noise-limited energy resolution of 4 eV. Based on the findings of these experiments, we suggest improvements that could be made to TES design to enhance their electron detection capabilities through the use of a dedicated electron absorber in the device with integrated electron optics. [ABSTRACT FROM AUTHOR]

Loading of WS2 can greatly improve water splitting H2 generation efficiency of CdS in experiments. Here, we constructed WS2/CdS(100) and WS2/CdS(110) heterostructures with smaller mismatches and explored their interaction energy and band offset by first-principles calculations. Our calculation suggests that the WS2/CdS(100) interface with a stronger binding energy is more active in experiments, while the WS2/CdS(110) interface is metastable. The band alignment between CdS and WS2 is highly dependent on the orientation of the interfaces, and WS2/CdS(100) and WS2/CdS(110) belong to type-I and type-II band alignments, respectively. Therefore, a metal electrode and hole scavenger may be essential in experiments to help WS2/CdS(100) efficiently trap electrons, and a suitable substrate and an appropriate growth temperature are also needed to composite the CdS(110) surface to achieve a higher photocatalytic efficiency. In addition, we performed a detailed analysis of the macroscopic average potential and found that the calculated accuracy of potential difference across the heterostructures due to slab thickness is less than 80 meV at WS2/CdS interfaces. In total, our calculations not only explain the physical reasons for the increased efficiency of WS2/CdS, but also provide a detailed guideline for the design of a more efficient synergistic catalyst. [ABSTRACT FROM AUTHOR]

The coupling of an electron gas confined by a harmonic potential and submitted to a strong magnetic field tilted in relation to the confining direction creates an excitation called here magneto-polariton. This work describes the origin of this excitation and calculates the energy eigenvalues for different tilted angles. It presents the reasons leading to the crossings and repulsions of the energy bands, the degeneracy of the states, the way the Fermi levels change with the magnetic field, the influence of an external electric field, and how the Hall resistance plateaus change with the change in the tilted angle. [ABSTRACT FROM AUTHOR]

Bi1−xBaxFeO3 (BBFO, x = 0, 0.03, 0.1) thin films were epitaxially grown on SrRuO3-buffered SrTiO3 (001) substrates by pulsed laser deposition. With increasing Ba content, the BBFO thin films show significantly reduced leakage currents but suppressed ferroelectric polarization. X-ray diffraction reciprocal space mappings and Raman spectra indicate a structural evolution from a rhombohedral-like to tetragonal-like phase in the BBFO thin films. Optical absorption and photoelectron spectroscopy measurements demonstrate a modulation of energy band structures in the BBFO thin films. With A-site Ba acceptor doping, the BBFO thin films exhibit a blue-shift of optical bandgap and an increase in work function. The energy positions of conduction and valence bands of the BBFO thin films have been modulated, and the Fermi level shifts down to the center of the forbidden band, but acceptor-doped BFO thin films still show n-type conduction. The presence of extra oxygen vacancies by acceptor doping is supposed to make contribution to conduction behavior. This study provides a method to manipulate the functional properties and gives insights into the physics of Ba doping in BFO thin films. [ABSTRACT FROM AUTHOR]

The body–boundary correspondence refers to the relationship between the body and boundary states of topological insulators (TIs). In TIs, the presence of boundary states is connected to the bulk topological properties of the material. The topology can be identified by studying the energy of the topological modes within the bulk bandgap. However, not all topological materials exhibit boundary states within the insulating energy gap. In many cases, the presence of boundary states can be hidden or masked by the bulk energy bands, making it difficult to measure TIs. Recent experiments have shown that defects, which are commonly found in crystalline materials, can be used as probes to explore higher-order topologies that have been recently realized on various platforms. These defects can generate fractional charges and stable bound states in the dispersion region, allowing us to observe the clear body–disclination correspondence. We have performed simulations using a coupled acoustic cavity system with C3 and C5 symmetries to investigate the body–disclination correspondence in topological crystal insulators (TCIs) in the field of acoustics. Simulation and theoretical results have demonstrated that defects such as disclinations can be used to probe higher-order topologies that were previously unobservable in three-dimensional structures. This approach allows us to detect fractional mode charges and stable bound states, which are crucial for understanding the topological nature of TCIs. Our work demonstrates the potential of using disclination defects to study the intricate relationship between the body and boundary states in topological materials, particularly in the context of acoustics. [ABSTRACT FROM AUTHOR]

This paper provides a numerical analysis of the topological valley kink states along both zigzag and armchair domain walls of a dielectric two-dimensional photonic crystal (PC), considering the photonic energy band folding mechanism. By engineering the side length of triangular holes in a honeycomb PC, we created inequivalent valleys in the momentum space. We utilized two adjacent valley PCs with inverted structures to induce a topological transition of the TE mode energy band as it crossed the interface. Further research into the projected energy bands along both zigzag and armchair directions revealed that topologically protected valley kink states can be supported by both configurations. The zigzag interface enabled valley waveguides to transport chiral optical fields at the 0°, 60°, and 120° bending angles, while maintaining their backscattering immune properties. The armchair interface, on the other hand, supported the straight propagation. By combining both armchair and zigzag interfaces, the valley waveguide can facilitate bending propagation at 90° and 180°, while also enabling the equal splitting of chiral fields at the intersection between these two interfaces. Our analyzation can be helpful to improve the applications of valley waveguides in integrated photonics. [ABSTRACT FROM AUTHOR]

We present a simplified tight-binding (TB) model to describe the low-energy physics of monolayer 1T' transition metal dichalcogenides (TMDCs). The TB model is constructed by combining symmetry analysis and first-principle calculations. Our TB model accurately reproduces the electronic structures near the Fermi energy and provides a better representation of energy band inversion. By considering spin–orbit coupling (SOC), our TB model successfully reproduces the opening of the bandgap, characterizes nontrivial topology, and predicts corresponding helical edge states. Additionally, using this TB model, we observe that quantized electronic conductance remains robust under significant disorder intensity. However, the robustness of the edge states can be suppressed by the Zeeman fields and SOC strength in the scattering zone. Furthermore, moderate concentrations of vacancy disorder destroy the topological protection and eliminate quantized conductance. Our TB model serves as a starting point for a comprehensive understanding of the properties of these materials and can guide future research on superconductivity, strain, and correlation effects. [ABSTRACT FROM AUTHOR]

Electronic transitions are observed for the O 2 + –Ar and O 2 + –N2 complexes over the 225–350 nm range. The transitions are not associated with recognized electronic band systems of the respective atomic and diatomic constituents (Ar+, Ar, O 2 + , O2, N 2 + , and N2) but rather are due to charge transfer transitions. Onsets of the O 2 + –Ar and O 2 + –N2 band systems occur at 3.68 and 3.62 eV, respectively, corresponding to the difference in the ionization potentials of Ar and O2 (3.69 eV), and N2 and of O2 (3.51 eV), suggesting the band systems arise from intramolecular charge transfer transitions to states correlating with O2 (X 3 Σ g − ) + Ar+ (2Pu) and O2 (X 3 Σ g − ) + N 2 + (X 2 Σ g + ) limits, respectively. The dominant vibronic progressions have ωe values of 1565 cm−1 for O 2 + –Ar and 1532 cm−1 for O 2 + –N2, reasonably close to the value for the neutral O2 molecule in its X 3 Σ g − state (1580 cm−1). Higher energy band systems for O 2 + –Ar and O 2 + –N2 are assigned to transitions to states correlating with the O2 (a1Δg) + Ar+ (2Pu) and O2 (a1Δg) + N 2 + (X 2 Σ g + ) limits, respectively. [ABSTRACT FROM AUTHOR]

In this work, we study the electronic properties of nanotubes with spin–orbit interaction that exhibit a spin Hall effect. Nanoribbons made of these materials are expected to have topologically protected states. The lack of edge states in a seamless tube eliminates the possibility of finding a topological edge state. The spin–orbit interaction breaks the degeneracy of Dirac's cones and eliminates the chance of finding a metal nanotube. As a consequence, this makes all nanotubes with spin–orbit interaction trivial band insulators. We focus our attention on two features. First, we study the energy band gap as a function of the diameter of the nanotubes. Then, we concentrate on controlling the bandgap of a nanotube by applying an external radial electric field. Finally, we discuss the possibility of using one of these tubes as a field-effect transistor. [ABSTRACT FROM AUTHOR]

Copper in vegetables can enter the human body, and excessive copper may cause uncomfortable symptoms; thus, it is urgent to test copper ions for safety concerns. Herein, we prepared Zn2GeO4:Mn2+,In3+ (ZGO:Mn,In) persistent luminescent nanoparticles (PLNPs) and then grafted glutathione for the determination of copper ions. ZGO:Mn,In was prepared by doping In3+ in ZGO:Mn to improve the emission at 532 nm under excitation at 258 nm. The doping amount, temperature, time, and pH were carefully optimized for a stronger emission intensity than ZGO:Mn. The fractional densities and energy band gaps were calculated by density functional theory, revealing the excitation enhancement mechanism of ZGO:Mn,In. The surface of ZGO:Mn,In was modified with carboxyl groups for linking glutathione to specially identify Cu2+ ions. The identification resulted in the aggregation-induced quenching of PLNPs' emission. Thus, the sensor exhibited good selectivity for copper ions, and the composite was successfully applied to the detection of copper ions in serum and vegetable samples. [ABSTRACT FROM AUTHOR]

The electronic structure and related electronic properties of two novel isostructural octacyanometallates Cd2(H2O)4[MoIV(CN)8]·2H2O and Cd2(H2O)4[WIV(CN)8]·2H2O are described from a combined experimental and computational approach. The impact that the octacoordinated heavy metals W and Mo have on the electronic structure and optical response of isostructural materials whose electronic properties strongly depend on the crystal structure is discussed. It is found that the effect of the polarization power of the metal centers, combined with the ligand field of cyanos, produces considerable changes in the electronic structure and, consequently, in the band gap energy. The ab initio calculations, which were performed with generalized gradient PBE and hybrid HSE06 density functionals, accurately reproduce the electronic structure of [Mo(CN)8]4− and [W(CN)8]4− building units, revealing that the electronic transitions associated with the band gap energy have an origin in the charge transfer phenomena of metal to ligand nature. Moreover, the optical band gap transitions have an allowed indirect behavior in the Γ → M → D direction which is associated with the (x2 − y2) → π* transition. The allowed direct and indirect (experimental and theoretical) band gap energies together with the exciton effective masses are reported. [ABSTRACT FROM AUTHOR]

Cesium-lead-bromide (CsPbBr3) has shown promise in thin film photovoltaics due to its desirable energy band gap, charge mobility and chemical and thermal stability. The low solubility of its single crystal in organic solvents has driven development of the two-step spin-coating technique. In this work, precursor solutions of different PbBr2 and CsBr concentrations were spin-coated and investigated via Photoelectron Spectroscopy. The properties of the CsxPbyBrz film in cross-section demonstrate this method leads to varying stoichiometries, work functions and band gaps through the thickness. This anisotropy of the perovskite thickness has ramifications for design of photovoltaic devices. [ABSTRACT FROM AUTHOR]

Metal chalcogenides, as a new class of semiconductor materials, have a broad range of applications in synthetic chemistry due to their rich structures and excellent properties. We have synthesized two selenoantimonates A4Zn2Sb2Se7 [A = Rb(1), Cs(2)] under solvothermal conditions in the visible region using a band gap optimization strategy with alkali metals as structure-directing agents. Compounds 1 and 2 have a two-dimensional layered structure consisting of charge-balanced Rb+(1) or Cs+ (2) cations and [Zn2Sb2Se7]4- anions with novel 20-membered rings (20-MR) [Zn6Sb4Se10] with an aperture of 5.6949 × 13.7741 Ų formed in the middle. Furthermore, we have investigated the crystal structure, band gap, photoelectronic properties, and energy band structure. [ABSTRACT FROM AUTHOR]

Red phosphorus (RP), as a talented semiconductor, is widely employed in the field of photocatalysis owing to its superior stability and optical properties. However, RP's inherent poor conductivity and rapid carriers’ recombination significantly impede its efficient photoelectrochemical (PEC) applications. Herein, non‐homogeneous porous RP particles (NPRPs) are prepared via a ball milling‐assisted hydrothermal strategy, which provides more chemical reaction sites and fast carriers transportation rates for sensitive PEC sensing. Experiments and computational findings reveal that NPRPs incorporating oxygen doping possess staggered energy band structures along with potential driving forces, which synergistically promote the separation and migration of carriers. Furthermore, carbon nanotubes are introduced to bridge the NPRPs for constructing a conductive network, and a uniform and fully‐integrated photoelectrode array is custom‐made in batches through zonal template‐filtration. As an illustration, aptamer‐mediated PEC sensors for trace amoxicillin (AMO, an artificial antibiotic) in various samples exhibit ultra‐high sensitivity (0.43 nm) and robust selectivity. Such a PEC aptasensing prototype based on NPRPs arrays, with tunable detection throughput, holds great potential for rapid and on‐site screening of massive specimens. More meaningfully, this study offers an innovative paradigm for elemental semiconductors to efficiently transport carriers in the photoelectrocatalytic applications. [ABSTRACT FROM AUTHOR]

The self-rectifying memristor (SRM) is a promising device prototype for high-density three-dimensional (3D) integration and high-efficiency in-memory computing (IMC) by virtue of its ability to effectively suppress sneak current, simple device structure, and low energy consumption. Theoretically understanding the intrinsic mechanisms of SRM is a matter of concern. Here, we fabricated a Ta/TaOx/HfO2/Pt-stacked SRM exhibiting >103 on/off ratio, rectification ratio, and nonlinearity. The SRM can be repeatedly programmed by more than 106 pulses and demonstrates robust retention and high scalability (∼59 Mbit). A reasonable interface model for this SRM is established based on first-principles calculations. Using self-energy corrected density function theory, we calculate the barrier heights at each interface. Detailed I–V curve fitting and energy band analysis are performed and computationally verified to explain the intrinsic reasons for resistive switching, self-rectifying, and nonlinear behaviors. The work may advance the development of SRM prototype to enable energy-efficient 3D IMC. [ABSTRACT FROM AUTHOR]

The ultrafast dynamics of photoexcited charge carriers are studied in micron‐scale crystals composed of the inorganic perovskite CsPbBr3 with time‐resolved terahertz spectroscopy. Exciting with photon energy close to the band edge, it is found that a fast (<10 ps) decay emerges in the terahertz photoconductivity with increasing pump fluence and decreasing temperature, dominating the dynamics at 4 K. The fluence‐dependent dynamics can be globally fit by a nonlinear recombination model, which reveals that the influence of different nonlinear recombination mechanisms in the studied pump fluence range depends on temperature. Whereas the Auger scattering rate decreases with decreasing temperature from 77 to 4 K, the radiative recombination rate increases by three orders of magnitude. Spectroscopically, the terahertz photoconductivity resembles a Drude response at all delays, yet an additional Lorentz component due to an above‐bandwidth resonance is needed to fully reproduce the data. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) with stable crystalline porous structures and flexible assembly properties contribute to the direct photocatalytic synthesis of H2O2 to meet the growing global demand. To address the challenges of insufficient redox capacity and photogenerated carrier recombination of COFs, S‐scheme heterojunction is constructed from COFs with quantum dots (QDs) to improve the photocatalytic production of H2O2. Herein, 0D ZnCdS QDs (ZCS) uniformly anchor on the surface of a 2D conjugated tetrathiafulvalene‐based COF (TT‐COF), affording the S‐scheme heterojunction TT‐COF/ZCS. Formation of S‐scheme heterojunction effectively prevents the agglomeration of ZCS, modulates the energy band structure of TT‐COF, and enhances the migration of photogenerated carriers and redox ability. As a total consequence, the optimized heterojunction (TZ‐40) is able to afford H2O2 in the yield up to 5171 µmol g−1 h−1 under visible light irradiation with H2O and O2, much higher than those for TT‐COF, 2520 µmol g−1 h−1, and ZCS, 2647 µmol g−1 h−1. The present result demonstrates the great potential of COFs/QDs‐based S‐scheme heterojunctions for photocatalytic applications including photocatalytic H2O2 production. [ABSTRACT FROM AUTHOR]

Semiconductor nanostructures with surface defect‐mediated chemistry have garnered pronounced interest due to their exceptional photo‐induced intracellular bio‐catalytic (enzyme‐mimicking) responses. However, designing defective nanozymes with pH‐responsive multi‐bio‐catalytic functions without any dopants is challenging. Herein, oxygen‐deficient “trojan horse‐like” folate‐functionalized, L‐arginine‐coated ceria (FA‐L‐arg‐CeO2) nanozymes with synergistic multi‐enzyme‐mimicking and anti‐cancer potential are introduced. Intrinsic surface oxygen vacancies (VO●) are strategically created in the nanozymes under kinetically favorable synthesis conditions. Increased surface VO● promotes band structure reconstruction and amplified photochemical‐response efficacy under single laser irradiation (808 nm), outperforming the defect‐free commercial nano‐CeO2 in rapid anti‐tumorigenic activities. Through folate receptor‐mediated endocytosis, these biostable nanozymes localized in MDA‐MB‐231 cells (84% in 48 h) and demonstrated NIR‐accelerated enzymatic functions depending on the pH of the biological milieu. The reduced band gap energy facilitated effective electron‐hole separation, up‐regulating in vitro photo‐redox reactions that impart exceptional therapeutic potential and inhibit 62% cell metastasis within only 12 h. By perturbing intratumoural redox homeostasis, VO●‐rich FA‐L‐arg‐CeO2 nanozymes unanimously killed 86% of MDA‐MB‐231 cancer cells while preferentially shielding benign L929 cells. Transcending beyond conventional drug‐loaded or dopant‐incorporated‐CeO2 nanoplatforms, these defective multi‐modal nanozymes unravel a new avenue for developing smart, low‐cost, bio‐active agents with enhanced efficacy and bio‐safety. [ABSTRACT FROM AUTHOR]

In an effort to improve the light absorption efficiency of the photocatalyst, g-C 3 N 4 nanosheets with visible light response have been prepared by roasting method, and the g-C 3 N 4 /CdZnS composite catalyst with 2D/0D architecture has been prepared by hydrothermal method after ultrasonic thinning. The g-C 3 N 4 /CdZnS/MoS 2 composite catalyst with 2D/0D architecture has been synthesized by secondary hydrothermal method. TEM analysis proves that a close heterogeneous interface has been formed between g-C 3 N 4 and CdZnS, and between CdZnS and MoS 2. The ultraviolet diffuse reflectance spectrum shows that MoS 2 has a wide light absorption range, which effectively enhances the light utilization ratio of the composite catalyst. The energy band structure diagram and photoelectrochemical test results show that a continuous stepped type II ternary heterojunction is formed among g-C 3 N 4 , CdZnS and MoS 2 , which promotes its separation of photogenerated charges. When the loading mass fraction of g-C 3 N 4 and MoS 2 is 4%, the hydrogen evolution rate of g-C 3 N 4 /CdZnS/MoS 2 composite catalyst is 57.02 mmol g−1 h−1 under visible light, which is exceeding 20% that of g-C 3 N 4 /CdZnS and 4.79 times and 44.9 times higher than that of CdZnS and g-C 3 N 4 , respectively. The two-dimensional structure of g-C 3 N 4 and MoS 2 significantly improves the stability of the composite catalyst. This work offers feasible ways for ternary heterogeneous photocatalyst construction. • The g-C 3 N 4 /CdZnS/MoS 2 composite catalyst was formed by secondary hydrothermal method. • A unique 2D/0D sandwich structure was formed between g-C 3 N 4 , CdZnS and MoS 2. • A close heterogeneous interface formed between g-C 3 N 4 and CdZnS, CdZnS and MoS 2. • The hydrogen evolution rate of g-C 3 N 4 /CdZnS/MoS 2 is 57.02 mmol g−1 h−1. [ABSTRACT FROM AUTHOR]

We present a new scheme for Majorana modes in systems with nonsymmorphic-symmetry-protected band degeneracy. We reveal that when the gapless fermionic excitations are encoded with conventional superconductivity and magnetism, which can be intrinsic or induced by proximity effect, topological superconductivity and Majorana modes can be obtained. We illustrate this outcome in a system which respects the space group P4/nmm and features a fourfold-degenerate fermionic mode at (π, π) in the Brillouin zone. We show that in the presence of conventional superconductivity, different types of topological superconductivity, i.e., first-order and second-order topological superconductivity, with coexisting fragile Wannier obstruction in the latter case, can be generated in accordance with the different types of magnetic orders; Majorana modes are shown to exist on the boundary, at the corner and in the vortices. To further demonstrate the effectiveness of our approach, another example related to the space group P4/ncc based on this scheme is also provided. Our study offers insights into constructing topological superconductors based on bulk energy bands and conventional superconductivity and helps to find new material candidates and design new platforms for realizing Majorana modes. Topological superconductors are highly sought-after systems with potential applications in topological quantum computing. Here, the authors propose a scheme for realizing topological superconductivity based on the bulk energy bands and conventional superconductivity. [ABSTRACT FROM AUTHOR]

Low efficiency of photogenerated electron–hole separation has been a challenge for organic conjugated polymer photocatalysts. Our preceding studies have revealed that polymers containing B←N coordination bonds can form a localized built-in electric field that effectively promotes photogenerated charge separation. However, B←N coordination units are still scarce and require more examples to find regularities in their structural design. The systematic development and testing of B←N coordination units is necessary for the efficient development of subsequent polymers containing B←N coordination bonds. In this work, three conjugated polymers containing B←N coordination bonds, PBN–Ni, PBP–Ni, and PBS–Ni, were synthesized by changing the substituents of the boron atoms and introducing narrow-band thiophene units to form conjugate and energy band gradients. The energy band modulation and localized built-in electric field construction were both achieved as planned, while the bandgap and photogenerated charge transport capabilities caused performance discrepancies. The experimental results showed that PBN–Ni had a better photocatalytic hydrogen evolution (HER) performance, reaching 104.6 μmol h−1 (λ > 420 nm). The optimal optical absorption edge of PBS–Ni was up to 643 nm, but the HER was lower, at 33.2 μmol h−1 (λ > 420 nm, 1% Pt). PBP–Ni optimized some of the optical absorption efficiencies (511 nm) while ensuring the HER activity (96.6 μmol h−1, λ > 420 nm). This work tentatively explores the characterization of the B←N coordination bond-containing base units serving as photocatalysts and provides the basic model experience and data reference for the subsequent expansion of B←N coordination bond-containing units and the development of B←N coordination bond-containing copolymer systems. [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]

One of the main challenges most organic photodiodes (OPDs) facing is to overcome the traditional trade‐off between ultralow dark current and high responsivity (R) in existing research. Here, van der Waals multilayer OPD based on water transfer printing method, termed hybrid bulk‐heterojunction (BHJ)/planar‐heterojunction (PHJ) (B‐PHJ) framework, is constructed making certain the high‐quality interface and novel two‐phase energy band alignment between the active and barrier layer with noise suppression and photovoltaic complement simultaneously. The prepared OPD exhibits the combined advantages of ultralow dark current (0.2 nA cm−2 at −1 V) and high responsivity (0.49 A W−1 at 850 nm). As a result, these superimposed effects enable the device to feature a superior liner dynamic range (LDR) of 210 dB and a specific detectivity of 1014 Jones to address the conventional responsivity‐noise trade‐off. The results reveal that the balance dynamics of charge transfer and charge blocking in van der Waals hybrid two‐phase framework OPD, may inspire the development of next OPDs. Finally, its diverse practical application potential is demonstrated through long‐distance misaligned photoplethysmography (PPG) measurement. [ABSTRACT FROM AUTHOR]

In this paper, the structure and electronic properties of InP/PtS 2 heterojunction as well as the photocatalytic and solar hydrogen production efficiency are studied by first principles. Studies have shown that InP/PtS 2 heterojunction is type II band alignment, typical Z heterostructure, has strong light absorption coefficient in the absorption spectrumand, InP/PtS 2 heterojunction with an indirect bandgap of 1.97 eV，the band edge positions that meet the energy band prerequisites for water splitting across different pH levels，The band edge positions and light absorption capabilities have been modified through biaxial strain, with tensile strain enhancing the absorption capacity within the visible light spectrum ranging from 450 to 800 nm(nm). The InP/PtS 2 heterojunction achieves a solar-to-hydrogen conversion efficiency (ηSTH) of 32.5%, which is higher than that of most heterojunctions. The InP/PtS 2 heterojunction is anticipated to emerge as a promising contender for the next generation of photocatalysts. InP/PtS 2 heterojunction is a typical direct Z-scheme heterojunction, which can change its electronic and optical properties under strain, and may contribute to the fields of water splitting. The solar-to-hydrogen efficiency of the InP/PtS2 heterostructure can reached 32.5%. The absorption coefficient in the visible range is enhanced by the application of strain. [Display omitted] • Compared with InP monolayer and PtS 2 monolayer, InP/PtS 2 heterojunctions have better visible light absorption efficiency. • The InP/PtS 2 heterojunction achieves a solar-to-hydrogen conversion efficiency (ηSTH) of 32.5%, which is higher than that of most heterojunctions. [ABSTRACT FROM AUTHOR]

This study explores the development of eco-friendly biocomposite films incorporating Poly(vinyl alcohol) (PVA), Alginate, and Cyclotrichium niveum (C. niveum) extract. The research emphasizes the fabrication of PVA/Alginate blend biocomposites produced by solvent casting with varying concentrations of C. niveum, analyzing their physicochemical, biochemical, and optical characteristic features. These biocomposites exhibited enhanced properties making them suitable to for applications such as packaging, and agricultural films. Significant outcomes of the research include the biocomposites improved thermal stability and semiconductor properties, evidenced by the decrease in band gap energy as the concentration of C. niveum increases. This work underscores the crucial role of integrating natural and synthetic polymers to address environmental challenges posed by traditional plastics, steering the field toward sustainable material solutions. [ABSTRACT FROM AUTHOR]

Effect of VI group elements (O, S, Se, Te) modification on the electronic properties of two-dimensional AlN were investigated by first-principles calculation method using density functional theory. The calculation results indicate that after O modification, the energy bands of the two-dimensional AlN system undergo splitting, thereby transforming into magnetic materials. After modification with S, Se and Te, the electron density of states curves of the two-dimensional AlN exhibit complete spin up and spin down symmetry, forming a non-magnetic structure. From the density of states graph, it can be seen that the density of states near the Fermi level is mainly contributed by the p-state electrons of the modified atom and the p-state electrons of the N atom. The bottom of the conduction band gradually moves towards the lower energy region, causing the absorption wavelength threshold of two-dimensional AlN to shift from the ultraviolet region to visible light. Therefore, the modified two-dimensional AlN improves its photocatalytic efficiency and has the potential to be used in the visible light responsive optoelectronic and spin electronic devices. [ABSTRACT FROM AUTHOR]

This study's main focus was on the process by which Ciclopirox adhered to AlN nanostructures, Calculations using the density functional theory were done to reach this goal. The calculations encompassed the assessment of Ciclopirox's adsorption energy, the evaluation of the energy band gap, the analysis of variations in the energy band gap, the examination of charge transfers, and the characterisation of the types of interactions that arise from Ciclopirox's adsorption onto AlN nanostructures. We carried out an investigation using the AIM method to explore deeper into the binding properties between the studied AlN nanostructures and Ciclopirox. Our discoveries provide light on the Ciclopirox/AlN nanosheet interaction's electrostatic characteristics. Moreover, the presence of Ciclopirox led to an augmentation in the electrical conductivity of the AlN nanostructures. This intriguing outcome suggests the potential application of these AlN nanomaterials as chemical sensors, capable of generating an electronic signal upon detection of this chemically modified amino acid. The observed sensitivity sequence indicated that the AlN nanosheet exhibited the highest sensitivity, followed by the AlN nanotube and the AlN nanocluster. In conclusion, our study provides compelling evidence supporting the AlN nanosheet as an excellent choice for the detection of Ciclopirox compared to other AlN nanostructures. [ABSTRACT FROM AUTHOR]

Precise regulation of phase structure and energy band distribution in CdS endow it with improved photocatalytic hydrogen evolution activity. [Display omitted] • A controllable phase structure modulation is implemented in phase junction CdS. • The transition region is introduced by suitable boundary width in phase junction. • The band distribution transmission mode is optimized by above cooperative effect. • Outstanding photocatalytic H 2 production is achieved in the phase junction system. An in-depth understanding of structure-activity relationship between the phase constitution and solar-to-hydrogen (STH) conversion efficiency is conducive to guiding the optimization route of targeted photocatalyst candidates, further establishing advanced photocatalytic systems. Herein, based on the concept of phase engineering, we encompassed the crystalline phase of CdS and achieved precise regulation of phase proportion as well as phase boundary width in the phase junction for the first time. The above cooperative effect not only modifies energy band distribution for sufficient redox potentials, but also guarantees the reverse migration orientation of photogenerated carriers in phase junction, thereby endowing photocarriers with a prolonged lifetime. Compared to pure cubic or hexagonal phase (72.6 or 101.1 μmol h−1 g−1), this CdS system with optimized phase junction demonstrates an improved photocatalytic hydrogen evolution activity of 1.04 mmol h−1 g−1 and favorable stability without cocatalyst assistance, which mainly stems from an efficient protons reduction process interacting with long-lived photogenerated electrons. This research explores the mechanism behind phase regulation and its relationship with junction capability, providing a powerful strategy to manipulate crystal phase distribution and paving a feasible avenue for other phase-dependent photocatalysts towards rational design of heterostructures based on different phases in solar energy conversion field. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides (TMDCs) are among the most exciting materials in nano-size particles. In this study, MX2 (M = Mo and W; X = S, Se, and Te) nanotubes and monolayers were evaluated to show the structural, mechanical, and electronic properties. The results showed that the stability of MX2 monolayers changes similarly to nanotubes with the sequence of MS2 > MSe2 > MTe2 (M = Mo and W). Besides, MX2 nanotubes and monolayers are semiconductors, and the band gap energy increases with a similar sequence with stability properties. The structural stability and band gap energy of WX2 structures are more than MoX2 structures. Young's modulus of nanotubes was studied with density functional theory (DFT) and molecular dynamics (MD) simulations with Stillinger-Weber (SW) potential methods. The results are similar to the formation and band gap energy showing that Young's modulus of the MX2 structures is in order of MS2 > MSe2 > MTe2 (M = Mo and W) and WX2 > MoX2 (X = S, Se or Te). Structural defects in monolayers, which were M-vacancy (VM), X2-vacancy (VX2), M-X2-vacancy (VM-X2), and M-X4-vacancy (VM-X4), were studied and it showed that the mechanical properties could be decreased. However, the defects do not affect electronic properties. [ABSTRACT FROM AUTHOR]

The compound, mercury bismuth sulphide (HgBi2S3), represents a promising semiconductor within the II–V–VI group, demonstrating potential as a solar cell absorber layer. However, its synthesis and investigation through the successive ionic layer adsorption and reaction (SILAR) method have remained unexplored. This study focuses on the successful synthesis of HgBi2S3 nanoparticles using the SILAR technique atop wide band gap n-type semiconducting titanium dioxide (TiO2) thin films. Characterization via X-ray diffraction (XRD) confirmed the synthesis, revealing an average crystallite size of 93.83 nm. The lattice strain percentage was measured at 0.1467 with a dislocation density of 1.13 × 10−4 1/nm2. Scanning electron microscopy (SEM) analysis showcased the spherical morphology of the nanoparticles, exhibiting average sizes of 169, 238 and 329 nm corresponding to 5, 10 and 15 SILAR cycles, respectively. The thickness of the TiO2/HgBi2S3 composite thin film ranged from 12 to 18 µm. Notably, sensitizing the TiO2 film with HgBi2S3 nanoparticles resulted in a substantial reduction in the contact angle by ~24°. Optical studies demonstrated a significant decrease in the energy band gap of TiO2 from 3.06 to 1.6 eV post-sensitization with HgBi2S3 nanoparticles, indicating enhanced light absorption capabilities. Interestingly, the energy band gap of the TiO2/HgBi2S3 composite thin film remained consistent across different SILAR cycles. Moreover, electrochemical impedance spectroscopy and photoelectrochemical analyses revealed the intriguing performance characteristics of the TiO2/HgBi2S3 composite thin film, showcasing promising yet marginal enhancements. [ABSTRACT FROM AUTHOR]

We present the band gap engineering and morphological tuning of BaAl2O4:0.1% Sm3+, x% Tb3+ nanophosphors synthesized by citrate sol–gel method. Herein, the samarium (Sm3+) concentration is kept constant at 0.1%, while the concentration of terbium (Tb3+) is tuned from 0.5 to 2.5% with steps of 0.5%. X-ray diffraction confirms the hexagonal crystal structure of the BaAl2O4:0.1% Sm3+, x% Tb3+ nanophosphors. The reduction in crystallite size from 38 to 31 nm is noticed after doping and co-doping. Scanning electron microscope micrographs display evolution in morphology from multimodal grain-like structures to agglomerated pointy nanorods. Energy dispersive X-ray spectroscopy confirms all the main elements, although Sm is not detected due to the low content incorporated into the lattice. Transmission electron microscope results reveal that the particle size and shape can be controlled by varying concentrations of Tb3+. Diffuse reflectance spectra with the aid of the Kubelka–Munk function, reveal the energy band gap in the range of 2.6–5.3 eV. Under the excitation wavelength of 235 nm, photoluminescence studies reveal eight emission peaks located between 380 and 641 nm characteristic of Tb3+ ions. Upon the excitation wavelength of 402 nm, the emission spectra show four peaks positioned at 564, 601, 648 and 708 nm attributed to 4G5/2 → 6H5/2, 4G5/2 → 6H7/2,4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 transitions of Sm3+ ions, respectively. From the colour coordinate results, this nanophosphor can successfully play a significant role in green, yellow and red LED applications. [ABSTRACT FROM AUTHOR]

Flat bands – single-particle energy bands – in tight-binding lattices, aka networks, have attracted attention due to the presence of macroscopic degeneracies and their sensitivity to perturbations. They support compact localized eigenstates protected by destructive interference. This makes them natural candidates for emerging exotic phases and unconventional orders. In this review we consider the recently proposed systematic ways to construct flat band networks based on symmetries or fine-tuning. We then discuss how the construction methods can be further extended, adapted or exploited in presence of perturbations, both single-particle and many-body. This strategy has lead to the discovery of non-perturbative metal-insulator transitions, fractal phases, nonlinear and quantum caging and many-body nonergodic quantum models. We discuss what implications these results may have for the design of fine-tuned nanophotonic systems including photonic crystals, nanocavities, and metasurfaces. [ABSTRACT FROM AUTHOR]

The piezo‐phototronic effect is widely used to regulate the interface of multilayer structures to tune the transportation of carriers by mechanical strain‐induced piezoelectric polarization charges. Besides, such modulation of the interface can also be achieved by the flexoelectric polarization charges induced by the mechanical strain gradients. Therefore, it is expected these two kinds of polarization charges can cooperate. In this work, a flexible phototransistor array based on n‐AZO/p‐Si/n‐ZnO structure is successfully demonstrated. The piezoelectric and flexoelectric polarization charges generated at the interfaces of the collector junction and the emitter junction, combined with the natural hole barrier at the emitter‐based interface, leads to the excellent performance of phototransistor for the ultraviolet (UV) –near infrared (NIR) range. Moreover, strain/optical imaging based on the flexible phototransistor array under different wavelengths of light is systematically investigated. The physical mechanism of the coupling between piezo‐phototronic and flexoelectric effects is further studied by analyzing the energy band and found to be attributed to the improvement of the emission efficiency and base transport efficiency. This work not only proposes a high‐performance flexible phototransistor array but also provides a new methodology to effectively modulate the interface by coupling the piezo‐phototronic effect and the flexoelectric effect. [ABSTRACT FROM AUTHOR]

The built‐in electric field (BIEF) is of utmost importance for 2D optoelectronic devices, which are typically realized in heterostructures created through interfacial engineering. However, the limitations of the sharp field distribution, inevitable energy band discontinuity, and inflexible construction of 2D heterostructures restrict their application. In this work, a large‐scale, continuous, and controllable BIEF using monolayer WxMo1−xS2 alloys with tunable composition gradients is constructed. Density functional simulations demonstrate that a BIEF can be formed within the whole alloy due to the charge distribution resulting from the composition gradients. Accordingly, a monolayer WxMo1−xS2 alloy with a controllable composition gradient via two‐step chemical vapor deposition and confirmed the continuous tunability of the band structure and the variation in the composition gradient within the alloy is synthesized. Using the BIEF, 2D light‐emitting diodes (LEDs) based on WxMo1−xS2 alloys and achieve strong electroluminescence emission are constructed. A large BIEF facilitates charge carrier migration and recombination, and the external quantum efficiency (over 0.62%) is more than 5 times that of small BIEF LEDs. The study not only provides a novel approach for the on‐demand design of a BIEF but also provides an opportunity for potential applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Entropy‐based polymetallic oxides with configurational entropy, structure flexibility, and crystallographic orientation have been regarded as promising catalysts for oxygen evolution reaction (OER), due to their electronic energy band occupation, composition ligand stabilization, and “cocktail” effect. Herein, a rutile RuIrAgMnO2 oxide with an orientation along the (110) facets is first fabricated by a low‐temperature directional co‐pyrolysis strategy of metal salts on Ti foil at 300 °C. The quaternary oxide exhibits a texture coefficient of 1.13 along (110) facet, resulting from concerted shaping of Ag and Mn components presenting a vibrational entropy of 1.13 R (R is the gas content). In 0.5 m H2SO4, it displays an overpotential of 171 mV at 10 mA cm−2 for OER, running at a voltage for 340 h at 100 mA cm−2. The remarkably improved performance can be associated with the presence of the preferred (110) facets with in‐plane strains, which activate and stabilize OER process via electronic energy band reconstruction. More interestingly, the preferential orientation prevents the diffusion or dissolution of active metal ions caused by entropy‐dependent energy barriers, ensuring long‐term stability. This work can pave the way for entropy‐driven polymetallic oxides with optimal structures, disrupting the trade‐off between activity and stability in water oxidation. [ABSTRACT FROM AUTHOR]

The performance and scalability of perovskite solar cells (PSCs) based on 3D formamidinium lead triiodide (FAPbI3) absorber are often hindered by defects at the surface and grain boundaries of the perovskite. To address this, the study demonstrates the use of pyrrolidinium iodide for the in situ formation of an energetically aligned 1D pyrrolidinium lead triiodide (PyPbI3) capping layer over the 3D FAbI3 perovskite. The thermodynamically stable PyPbI3 perovskitoids, formed through cation exchange reactions, effectively reduce surface and grain boundary defects in the FAPbI3 perovskite. In addition to improved phase stability, the resulting 1D/3D perovskite film forms a cascade energy band alignment with the other functional layers in PSCs, enabling a barrier‐free interfacial charge transport. With a maximum power conversion efficiency (PCE) of ≈23.1% and ≈20.7% at active areas of 0.09 and 1.05 cm2, respectively, the 1D/3D PSCs demonstrate excellent performance and scalability. Leveraging this improved scalability, the study has successfully developed a mechanically‐scribed 1D/3D perovskite mini‐module with an unprecedentedly high PCE of ≈20.6% and a total power output of ≈270 mW at an active area of ≈13.0 cm2. The 1D/3D multi‐dimensional perovskite film developed herein holds great promise for producing low‐cost, high‐performance perovskite photovoltaics at both the cell and module levels. [ABSTRACT FROM AUTHOR]

Glucose, an abundant and renewable form of biomass, has garnered significant attention in research for its conversion into high‐value chemicals such as gluconic acid. Traditional methods for biomass transformation typically involve high energy input, elevated temperature, pressure, and costly systems. In contrast, photocatalysis emerges as a promising approach to produce organic molecules under mild conditions, harnessing energy from natural sunlight or lamps. This study presents the nitrogen‐enriched graphene with zeolite second Mobil–5 (NenG/ZSM‐5) photocatalyst, evaluated for generating high‐value chemicals (gluconic acid and leucodopaminechrome) under solar light irradiation. The NenG/ZSM‐5 photocatalyst, synthesized from nitrogen‐doped graphene and ZSM‐5, successfully converted dopamine into leucodopaminechrome (71.54 %) — a critical step in dopamine regeneration and transformed glucose into gluconic acid (85 %). The addition of ZSM‐5 to NenG provided stability and enhanced product selectivity. The outstanding performance of the NenG/ZSM‐5 photocatalyst can be attributed to its heightened solar light harvesting potential, appropriate energy band gap, and uniformly arranged π‐electron channels. This research focuses on solar conversion of glucose to gluconic acid and dopamine regeneration, with potential for further exploration in the research domain. [ABSTRACT FROM AUTHOR]

AbstractPure and boron modified Ag3PO4 powders with different boron contents (0–5 wt.%) were prepared. XRD, ATR-FTIR, XPS, SEM-EDX, UV-Vis DRS and PL analyses were conducted for the characterization of the prepared powders. Characterization studies indicated the reduction in the band gap energy, the presence of boron and no change in the morphology due to boron modification. The results of photocatalytic experiments showed that boron modification increased the activity of Ag3PO4. The UV light dye degradation efficiency increased from 63% to 84% for methyl orange (MO) and from 41% to 65% for methyl red by 3% boron modification. The reaction rate constant for MO increased by a factor of 1.7. Under visible light, the activity was similarly enhanced by boron modification. The photocatalytic degradation efficiency increased from 31% to 58% and the reaction rate constant increased by a factor of 2.3 by boron modification for MO under low intensity visible light. These results showed that boron modification enhanced the photocatalytic dye degradation activity of Ag3PO4 under both UV and visible light. This enhancement was attributed to the decrease in the band gap energy and the increase in the interaction of the dye molecules with the photocatalyst surface through boron species. [ABSTRACT FROM AUTHOR]

We investigate the energy band structure and transport properties of electrons in superlattice structure based on semi-Dirac material with one-dimensional periodic potentials of square barriers. The influence of different parameters on transmission probability in superlattice structure is studied. It is found that two new Dirac points are formed in the superlattice structure by adjusting the gap parameter. The position of the new Dirac points can be regulated by changing the size of the potential barrier, the ratio of well width to barrier width, and the gap parameter. Some forbidden bands appear in the transmission probability, the location and width of the forbidden bands can be regulated by changing the system parameters. [ABSTRACT FROM AUTHOR]

Gamma irradiation has emerged as a promising technique for tailoring the microstructures and, by extension, properties of nanoparticles embedded polymer composites. Despite extensive efforts to elucidate the gamma ray-induced changes in nanocomposites, there is still a notable lack of studies on the effects of low-doses on the properties of polymer nanocomposites. This leads to a quantitative investigation about the impact of low-dose gamma irradiation on the optical properties of graphite nanoflake (GnF)-reinforced polydimethylsiloxane (PDMS) nanocomposites (GnF/PDMS nanocomposites). A series of GnF/PDMS nanocomposites with different GnF concentrations ranging from 1 to 10 wt% was prepared, followed by gamma irradiation at specific doses ranging from 0.0 to 5.0 kGy. The analyses showed that even low-dose gamma irradiation causes microstructural changes in the nanocomposites, resulting in a proportional relation between their light absorption properties and gamma ray dose. In detail, the GnF/PDMS nanocomposites showed a gradual increase in light absorption, peaking at gamma irradiation dose of 5 kGy. For example, 4 wt% GnF/PDMS nanocomposite under the influence of 5 kGy gamma irradiation shows an average light absorption value of 96.3%, whereas nonirradiated sample at the same composites exhibits absorption value of 93.2%. The increase in absorption is attributed to the combined effects arising from microstructural alterations in the nanocomposites, including the improved dispersion of GnF and the restoration of carbon rings under gamma irradiation. Notably, the optical energy band gap of the nanocomposite samples reveals a decreasing trend with increasing gamma irradiation. Specifically, band gap for 4 wt% GnF/PDMS at 5 kGy radiation is 2.76 eV against 4.96 eV for non-irradiated pure PDMS. This study sheds light on the fundamentals of enhancing the light absorption characteristics of GnF/PDMS nanocomposites under low-dose gamma irradiation. [ABSTRACT FROM AUTHOR]

Molecular oxygen activation often suffers from high energy consumption and low efficiency. Developing eco-friendly and effective photocatalysts remains a key challenge for advancing green molecular oxygen activation. Herein, graphitic carbon nitride (g-C3N4) with abundant hydroxyl groups (HCN) was synthesized to investigate the relationship between these polar groups and molecular oxygen activation. The advantage of the hydroxyl group modification of g-C3N4 included narrower interlayer distances, a larger specific surface area and improved hydrophilicity. Various photoelectronic measurements revealed that the introduced hydroxyl groups reduced the charge transfer resistance of HCN, resulting in accelerated charge separation and migration kinetics. Therefore, the optimal HCN-90 showed the highest activity for Rhodamine B photodegradation with a reaction time of 30 min and an apparent rate constant of 0.125 min−1, surpassing most other g-C3N4 composites. This enhanced activity was attributed to the adjusted band structure achieved through polar functional group modification. The modification of polar functional groups could alter the energy band structure of photocatalysts, narrow band gap, enhance visible-light absorption, and improve photogenerated carrier separation efficiency. This work highlights the significant potential of polar functional groups in tuning the structure of g-C3N4 to enhance efficient molecular oxygen activation. [ABSTRACT FROM AUTHOR]

Modulating of electronic structure of photocatalyst and integration of dual channel pathway are promising strategy for efficient photosynthesis of hydrogen peroxide (H2O2) from pure water without sacrificial agent and oxygen exposure. In this work, nontoxic aromatic dialdehyde is used to replace the commonly used toxic formaldehyde to form resorcinol‐phthalaldehyde resins through a hydrothermal method. The introducing of aromatic ring as π spacer increases the separation distance of electrons and holes to avoid their recombination. H2O2 can be produced via integrated oxygen reduction reaction (ORR) and water oxidation reaction (WOR) due to the suitable energy band positions and spatially separated reaction sites. Resorcinol‐p‐phthalaldehyde (RP) resin exhibits a promising H2O2 yield of 3351 µmol g−1 h−1 with high apparent quantum yield (AQY) of 14.9% at 420 nm and solar‐to‐chemical conversion (SCC) efficiency of 1.54%. This work provides a simple strategy to modulate the charge separation efficiency and redox reaction pathway on photocatalyst at molecular level design. [ABSTRACT FROM AUTHOR]

Two halogenated Schiff bases namely, (E)-1-(((2,6-dichlorophenyl)imino)methyl)naphthalen-2-ol (L1) and (E)-1-(((4-bromo-2,6-dichlorophenyl)imino)methyl)naphthalen-2-ol (L2) were synthesized and reacted with copper(II) nitrate trihydrate in ethanol to give Cu(L1)2 (1) and Cu(L2)2 (2). All the ligands and complexes were successfully characterized using FT-IR, UV-Vis, 1H & 13C-NMR as well as mass spectra and the purity was ascertained by elemental analysis. Electron paramagnetic resonance (EPR) was used to confirm the paramagnetic nature of 1 and 2. Furthermore, the single X-ray crystal structures of 1 and 2 were determined, confirming the formation of mononuclear species in which the Cu(II) center was bonded to two bidentate Schiff bases (L1 or L2) adopting a slightly distorted square planar geometry. Density Function Theory studies revealed that, complex 2 with lowest energy band gap (ΔE) of 2.49 eV is the most reactive among the compounds. α-Amylase and α-glucosidase assays were used to evaluate the antidiabetics potential of the compounds. Complexes 1 and 2 displayed very promising antidiabetic activities with IC50 values of 148.126 mM and 107.786 mM for α-amylase assay while it was 171.559 mM for acarbose (reference drug). The antioxidant potential of the compounds was investigated using nitric oxide (NO), ferric reducing ability power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. The compounds showed moderate to good antioxidant activities with 1 and 2 having IC50 values of 100.044 mM and 247.463 mM for NO scavenging assay, which relatively surpass Vanillin with IC50 value of 466.626 mM. All the compounds showed poor to moderate results against Escherichia coli, Staphylococcus aureus, Bacillus substilis, and Pseudomonas aeruginosa. However, none of them were active against Klebsiella pneumoniae. Generally, 1 and 2 displayed better antidiabetes, antioxidant, and antibacterial potential than L1 and L2. Predicted physicochemical and pharmacokinetic properties of all the compounds showed minimal violation of Lipinski's Ro5. [ABSTRACT FROM AUTHOR]

Redox‐active azo compounds are emerging as promising cathode materials due to their multi‐electron redox capacity and fast redox response. However, their practical application is often limited by low output voltage and poor thermal stability. Herein, we use a heteroatomic substitution strategy to develop 4,4′‐azopyridine. This modification results in a 350 mV increase in reduction potential compared to traditional azobenzene, increasing the energy density at the material level from 187 to 291 Wh kg−1. The introduced heteroatoms not only raise the melting point of azo compounds from 68 °C to 112 °C by forming an intermolecular hydrogen‐bond network but also improves electrode kinetics by reducing energy band gaps. Moreover, 4,4′‐azopyridine forms metal‐ligand complexes with Zn2+ ions, which further self‐assemble into a robust superstructure, acting as a molecular conductor to facilitate charge transfer. Consequently, the batteries display a good rate performance (192 mAh g−1 at 20 C) and an ultra‐long lifespan of 60,000 cycles. Notably, we disclose that the depleted batteries spontaneously self‐charge when exposed to air, marking a significant advancement in the development of self‐powered aqueous systems. [ABSTRACT FROM AUTHOR]

A dye-sensitised solar cell was fabricated using dry Ixora flower extract. The sensitiser was obtained by physical extraction using a mixture of ethanol and distilled water as solvent in the ratio of 7:3. The optical study of the sample was done within wavelength range of 230 nm to 1100 nm using spectrophotometer (UV- 750 series). The outcome shows an optimum absorption in the visible region of the EM spectrum, which shifted to the UV region when adsorbed onto a nano-porous TiO2 surface. An alternative peak of 0.95a.u in the visible region was observed with enhanced optical absorption across the infrared region of the spectrum. The absorption coefficient values suggest the extract absorbs light in the visible region, which was also confirmed with the relatively high extinction coefficient observed in the visible region of the EM spectrum. The extract exhibits a low transmittance in the visible range, which increases to over 99% in the red wavelengths. The extract has low reflectance of about 20% in the visible range, which falls lower as wavelength increases into the infrared region. The energy band gap (for direct transition) of 2.13 eV was obtained for dry Ixora dye extract. The fabricated solar cell performed a fill factor of 0.27, Jsc of 0.1273 mA/cm2, Voc of 0.7001 V, and conversion efficiency of about 0.02%. with these results, the dye extract of dry ixora flower can serve as a good photo-sensitiser for the fabrication of dye-sensitised solar cell. [ABSTRACT FROM AUTHOR]

Interfacial defects between perovskite and adjacent charge transport layers present a significant obstacle, hindering the enhancement of power conversion efficiency (PCE) and stability in perovskite solar cells (PSCs). To address this challenge, a dual‐interface modification is proposed to aim at improving the performance of mixed‐halide PSCs. Specifically, the hole‐collecting side is modified with 5‐Aminopyridine‐2‐carboxylic Acid (APC), while the electron‐collecting side is modified with 2‐thiopheneethylammonium chloride (TEACl). The multifunctional APC enhances charge transfer by tailoring the interface between the perovskite and poly(triarylamine) (PTAA) through multiple bonding interactions, thereby suppressing interfacial nonradiative recombination. Density functional theory studies reveal that APC on the perovskite surface induces uniform adsorption energy, promoting homogenous crystallization without residual stress. Additionally, APC interlayer eliminates the localized edge states induced by the iodine vacancies near the conduction band edge. Further improvement in the device performance is achieved by passivating the top perovskite surface with TEACl, leading to well‐matched energy bands and reduced vacancy trap states. As a result, champion cell achieves a PCE of 24.87% with an open‐circuit voltage of 1.188 V. Furthermore, The dual‐interface modification improves thermal stability due to enhanced ion‐migration activation energy. [ABSTRACT FROM AUTHOR]