A hybrid plasma magnetohydrodynamic (MHD) generator integrating a microwave (MW) plasma torch with surface dielectric barrier discharge (SDBD) electrodes is investigated to address low-conductivity limitations in plasma flow systems. The MW torch generates a high-temperature core plasma, while SDBD actuators produce surface plasmas near channel walls. Experimental results show that MW-only operation yielded no measurable output at the present measurement location, and SDBD-only mode produced minimal performance (0.128 V, 0.410 μW at 0.4 T and 50 LPM). Under maximum tested conditions, hybrid operation achieved 1.578 V and 62.253 μW, representing increases relative to the SDBD-only baseline at the same flow rate. The observed enhancement is interpreted as arising from SDBD-sustained carrier density in the downstream core of the MW plasma jet combined with wall-adjacent SDBD ionization, together improving current continuity across the power-generation electrodes. However, governing mechanisms of conductivity redistribution and current transport are interpreted as physically plausible pathways rather than directly measured quantities. This work demonstrates a laboratory-scale proof-of-concept for measurable enhancement under low-conductivity conditions.
Recently, halide perovskites and two-dimensional materials have emerged as promising platforms for energy conversion devices ranging from optoelectronics to energy harvesting devices. The performance of next-generation energy conversion devices is critically dependent on a fundamental understanding of materials structures, defects and interface properties at the nanoscale. Therefore, understanding the correlation between local structural features and material behavior is key. For this, scanning probe microscopy (SPM) provides the pathway to enable a wide range of associated material measurements locally and spatially at the nanoscale. A large body of SPM-based work has developed the understanding of energy conversion processes. Here, we review recent highlights of halide perovskites and two-dimensional materials, particularly focusing on their nanoscale functional properties characterized by SPM.
Developing efficient visible-light-driven photocatalysts is essential for large-scale water purification. Herein, a cocatalyst-free SnS2 (tin-disulfide) / g-C3N4 (graphitic carbon nitride) heterostructure is reported to have been developed via in situ hydrothermal growth of 2D SnS2 nanosheets over thermally polymerized g-C3N4. By optimizing the SnS2 loading, the SnS2/g-C3N4 (weight ratio of 1:1) composite exhibited a superior photocatalytic performance among various other tested weight fractions, achieving 96.90% methylene blue degradation within 45 min and 97.03% Pb2+ removal within 60 min under solar irradiation. Structural analyses confirm phase purity and strong interfacial integration, while optical studies reveal enhanced visible-light absorption and suppressed charge recombination. Density functional theory based calculations indicate electron transfer from g-C3N4 to SnS2, facilitating a Z-scheme mechanism and a reduced band-to-band recombination. Overall, the SnS2/g-C3N4 heterostructure demonstrates significant potential for sustainable environmental remediation for broad range of organic dyes and heavy ion removal from potable water.
To accurately describe the electronic behavior of strongly correlated materials, the Hubbard-U correction within density functional theory (DFT) is considered one of the most computationally efficient and reliable approaches among methods that deals with highly correlated materials. However, the Hubbard-U parameter is highly material dependent, making the first-principles determination of U essential for obtaining reliable results. In the conventional Hubbard-U approach, the same U value is applied to both spin channels. This approximation can artificially increase the energy separation between the spin-up and spin-down states, leading to spurious modifications of the electronic structure and consequently affecting the overall physical behavior of the system. In this work, we investigate the effect of spin-dependent Hubbard-U corrections on the electronic and magnetic properties of monolayer chromium trihalides, CrX3 (X = Cl, Br and I), within DFT. Compared to the conventional Hubbard-U approach, the spin-dependent U correction significantly modifies the spin-resolved band structures and yields better agreement with the experimental results. Consequently, the calculated exchange energies and nearest-neighbor exchange constants also show improved agreement with previously reported theoretical and experimental values. Our results indicate that the spin-dependent U method provides a more accurate description of magnetic interactions in CrX3 than the conventional method.
We investigated the magnetic and electrical transport properties of ∼100 nm Fe3O4 nanoparticles dispersed on reduced graphene oxide (RGO) sheets. XRD, Raman, and XPS confirm a crystalline Fe3O4 phase coupled to a graphitic RGO framework. Both pristine Fe3O4 and the composite show nonmetallic R(T) behavior, with the composite following Efros–Shklovskii variable-range hopping at low temperatures, indicating tunneling-dominated conduction via RGO. Magnetization measurements reveal symmetric M(H) loops with no exchange bias-like shift under zero-field-cooled conditions, while magnetoresistance shows a temperature-dependent sign reversal and a reproducible low-field anomaly. Direct comparison with a previously reported ∼25 nm Fe3O4/RGO system reveals pronounced differences in the R(T) crossover, loop asymmetry, and low-field magnetoresistance, establishing nanoparticle size as a key variable governing interfacial magnetotransport and supporting potential applications in low-temperature spintronic and magnetic-sensing devices.
Magnetic resonance imaging (MRI) relies on nuclear magnetic resonance of hydrogen atoms, with the Larmor frequency governed by static magnetic field (B0). While increasing B0 boosts the signal-to-noise ratio (SNR) and image quality, it comes with high costs and safety concerns, especially for patients with implants. To overcome this, enhancing the local magnetic field (H) in the region of interest has emerged as a safer alternative, with flexible metamaterial showing great potential. Here, we propose a newly developed conformal magnetic metasurface comprising of a 2 × 2 array with a nested resonant structure, which has demonstrated a 3.3-fold increase in local magnetic field strength for human bio-models. The proposed design is easily scalable, featuring copper patterns on a thin, flexible FR4 substrate (0.2 mm thick) to provide a more practical and cost-effective solution. This design utilizes inter-layer electromagnetic coupling for spatial localization of magnetic fields at the resonant frequency (∼64 MHz), matching the Larmor frequency of 1.5T MRI. Simulations and experiments on cylindrical phantoms confirm significant improvements in S-parameter, magnetic field, and RF magnetic field uniformity. Further simulations involving voxel phantom models of human leg corroborates the findings. This advancement holds potential for rapid clinical adoption, improving SNR, image resolution, and scan efficiency while ensuring patient safety.
Organic ferroelectric composite materials, owing to their high flexibility, ease of processing, chemical adaptability and better Curie transition temperature consideration, have attracted increasing attention in recent years. Their excellent piezoelectric properties make these ferroelectric composites promising candidates for energy harvesting and sensing applications. In this work, PVDF/DIPAB based organic ferroelectric composites were fabricated and characterized for beta phase, crystallinity, dielectric and ferroelectric properties enhancement. From these characterizations, 5wt% concentration (5DIPAB) arrived as the optimal concentration, with maximum d33 values reaching to 33pC/N. Then the fabricated 5DIPAB piezoelectric nanogenerator (PENG) device generated the maximum V of 13.5V and the maximum Isc of 3.5 µ A, a 6-fold rise compared to PVDF based PENG device outputs. Finally, the 5DIPAB device was used to demonstrate the human gait motion synchronizations and wireless IoT sensing application, to underscore its potential for use in performance monitoring, flexibility touch panels and wearable medical electronics.
We investigate the in-plane optical anisotropy and exciton–phonon interactions in bulk ReSe2 using temperature-dependent spectroscopic ellipsometry from 10 K to 302 K. Optical conductivity spectra measured at selected polarization angles relative to the Re–Re chain reveal strongly anisotropic excitonic absorption. The dominant and excitons exhibit pronounced Fano lineshapes, indicating interference between the discrete excitons and a sub-gap continuum. The temperature evolution of the exciton energies follows a Bose–Einstein model with an average phonon energy of about 15 meV, consistent with the in-plane optical phonons of ReSe2. The below-gap absorption shows an exponential, Urbach-like tail, but its anomalously large characteristic energy of about 550 meV and weak temperature dependence are incompatible with a phonon-induced Urbach tail. Band-gap extraction from the absorption tail of ReSe2 therefore requires particular caution. Together, these results reveal how strong exciton–phonon coupling shapes the excitonic optical response of this quasi-one-dimensional van der Waals semiconductor.
In this study, vanadium (V) doping into ZnO was utilized to tackle the limited performance of ZnO/CuO heterojunction diodes. V-doped ZnO (VZO) films with variable V concentrations were elaborately prepared by co-sputtering, and their properties were systematically investigated. Intriguing phenomena such as grain refinement, band gap widening, and carrier concentration increase were observed as V concentration increased. Various VZO/CuO heterojunction diodes were fabricated by a combination of co-sputtering and reactive sputtering. An optimal heterojunction with a V content of 0.28 at% exhibited a very high rectification ratio of 686, low ideality factor of 2.63, and a very low reverse saturation current of 3.79 × 10-13 A. Its rectification ratio was approximately 73-fold higher than that of ZnO/CuO diode. These results demonstrate that V doping can effectively tune the charge transport properties of ZnO for optimizing the current rectification performance of oxide-based heterojunction diodes.
An efficient hole transport layer (HTL)is critical for achieving high photovoltaic performance for the stable inverted perovskite solar cells (PSCs). Herein, a cross-linked hole transport molecule (c-H4TTFTB) was designed and developed via a straight forward acid-base condensation reaction between tetrathiafulvalene- derived tetrasulfuvanenobenzoic acid precursor (H4TTFTB) and 1, 3-propanediamine (PPA). The resulting c-H4TTFTB features robust imide functional groups that not only enable strong chemical adhesion to the perovskite surface but also effectively passivate undercoordinated lead ions at the perovskite/HTL interface. This dual functionality facilitates efficient charge transport from the perovskite absorber to the electrode, minimizing charge carrier recombination losses. As a result, the cross-linked c-H4TTFTB-based inverted PSC device show a power conversion efficiency of 20.7%, marking a significant advancement toward high-performance.
Porphyrin-based titanium metal-organic framework (Ti-MOF) composites were fabricated via solvothermal reactions using tetrakis(4-carboxyphenyl)porphyrin (TCPP) combined with two distinct titanium sources: anatase TiO2 and mixed-valence Ti3O5. The introduction of the TCPP ligand successfully extended light absorption into the visible region for both systems. Crucially, the choice of titanium precursor significantly governed the composite properties: the TiO2-based composite displayed superior charge-transfer characteristics, whereas the Ti3O5-based system exhibited distinct electron-transfer behavior driven by its intrinsic mixed-valence Ti3+/Ti4+ states. These results demonstrate that modulating the electronic structure of the underlying titanium oxide source is a highly effective strategy for tuning the functional performance of hybrid Ti-MOFs. This study provides fundamental insights into the design of advanced porphyrin-based titanium composites for future electrochemical and photocatalytic applications.
Plasmon-enhanced dye-sensitized solar cells (PDSSCs) offer a promising route to overcome the intrinsic light-harvesting limitations of conventional DSSCs. In this study, TiO2/Au plasmonic nanohybrids were synthesized via a facile sol–gel hydrothermal method, incorporating citrate-reduced Au nanoparticles prepared using the Turkevich method, which exhibits a characteristic surface plasmon resonance (SPR) peak at ∼525 nm. The in-situ integration of Au nanoparticles within the TiO2 matrix effectively broadened visible light absorption and promoted faster charge separation and electron transport through localized surface plasmon resonance (LSPR) induced hot-electron injection. The plasmonic DSSC device fabricated using TiO2/Au photoanodes demonstrated a remarkable enhancement in photovoltaic performance. It achieved a Power Conversion Efficiency (PCE) of 8.2%, significantly higher than the 6.5% obtained for the reference pristine TiO2 DSSC. A substantial increase in short-circuit current density (Jsc from 14.2 to 19.4 mA cm−2) further confirmed the superior light-harvesting and charge transport properties of the plasmonic architecture. These findings highlight the strong potential of TiO2/Au nanohybrids as efficient photoanodes for next-generation high-performance PDSSCs.
YBO3:Sm3+ phosphors with various Sm3+ concentrations ranging from 0.01 to 0.13 mol were successfully synthesized via high temperature solid-state reaction. Structural analysis confirmed that the prepared phosphors possessed a hexagonal phase without any secondary phase. Under excitation at 405 nm, the phosphors show the orange red emission peaks at 573 nm (4G5/2 → 6H5/2), 608 nm (4G5/2 → 6H7/2), and 654 nm (4G5/2 → 4H9/2). The maximum emission intensity was achieved at a Sm3+ concentration of 0.05 mol. The optimized phosphor showed CIE color coordinates of (0.568, 0.429) with a high color purity of 97.5%. The detailed minutiae of fingerprint with different levels (1-3) can be clearly observed. The obtained results indicate that the YBO3:0.05Sm3+ phosphor can be effectively utilized for latent fingerprint detection.
Faceted CdS/Bi2S3 core-shell heterostructured photoanodes were fabricated via hydrothermal synthesis of CdS followed by SILAR deposition of Bi2S3. Structural analyses confirm phase-pure hexagonal CdS and orthorhombic Bi2S3 forming an intimate CdS/Bi2S3 heterointerface. Electron microscopy reveals uniform CdS nanocrystals conformally coated with a Bi2S3 shell, forming a robust core-shell architecture. Optical measurements show enhanced visible-light absorption and a gradual extension of the absorption edge due to the increasing contribution of the narrow-band-gap Bi2S3 shell. Steady-state and time-resolved photoluminescence analyses demonstrate suppressed charge recombination and prolonged carrier lifetime after Bi2S3 incorporation. The optimized CdS/BS-2 photoanode delivers a photocurrent density of ∼1.30 mA cm−2 at 0 V vs. SCE, ∼30% higher than bare CdS. Mott-Schottky analysis indicates a cathodic shift in flat-band potential and increased donor density, facilitating improved charge separation. Electrochemical impedance spectroscopy demonstrates improved interfacial charge-transfer characteristics and reduced transport resistance for the optimized photoanode. The enhanced performance is attributed to improved light harvesting, efficient type-II band alignment, and suppressed recombination, demonstrating the potential of CdS/Bi2S3 heterostructures for photoelectrochemical applications.
The coupled effects of alloy composition, temperature, strain rate, and grain size on the deformation behavior of medium-entropy alloys (MEAs) remain insufficiently understood. In this study, molecular dynamics simulations were conducted to investigate the tensile behavior of crystalline CoZrTa MEAs using single-crystal and polycrystalline models. The effects of composition, temperature (100–900 K), strain rate (108–5 × 109 s−1), and grain size were evaluated through stress–strain analysis, Common Neighbor Analysis, Dislocation Extraction Algorithm, von Mises shear strain, and radial distribution function analyses. Alloy composition governs the strength–ductility balance, while increasing temperature reduces mechanical strength and promotes homogeneous plastic deformation. Higher strain rates increase flow stress, strain localization, and lattice disorder. Grain refinement within 10.79–15.56 nm exhibits Hall–Petch-like strengthening. These findings provide atomistic insights into structure–property relationships and support the design of high-performance CoZrTa MEAs under diverse thermomechanical conditions.
