We report the synthesis and multifunctional characterization of copper-reinforced Ba0.85Sr0.15TiO3 (BST) ceramic composites with Cu contents ranging from 0 to 40 wt%, prepared by a sol–gel route and densified using spark plasma sintering (SPS). X-ray diffraction and FT-IR analyses confirm the coexistence of cubic and tetragonal BST phases, while Cu remains as a chemically separate metallic phase without detectable interfacial reaction products. Microstructural observations reveal abnormal grain growth induced by localized liquid-phase-assisted sintering and progressive Cu agglomeration at higher loadings. Scanning electron microscopy reveals abnormal grain growth, with the average BST grain size increasing from approximately 3.1 µm in pure BST to about 5.2 µm in BST–Cu40% composites. Optical measurements show a continuous reduction in the effective optical bandgap (apparent absorption edge) from 3.10 eV for pure BST to 2.01 eV for BST–Cu40%, attributed to interfacial electronic states, defect-related absorption, and enhanced scattering rather than Cu lattice substitution. Electrical characterization reveals a percolation threshold at approximately 30 wt% Cu, where AC conductivity and dielectric permittivity reach their maximum values. Impedance spectroscopy and equivalent-circuit analysis demonstrate strong Maxwell–Wagner interfacial polarization, yielding a maximum permittivity of ~1.2 × 105 at 1 kHz for BST–Cu30%. At higher Cu contents, conductivity and permittivity decrease due to disrupted Cu connectivity and increased porosity. These findings establish BST–Cu composites as tunable ceramic–metal systems with enhanced dielectric and optical responses, demonstrating potential for specialized high-capacitance decoupling applications where giant permittivity is prioritized over low dielectric loss.

In this study, ultrathin CuIn_xGa_1-xSe₂ (CIGS) films with two distinct thicknesses were grown on n-Si substrates by pulsed laser deposition (PLD), with thickness controlled by varying the number of laser pulses. Au plasmonic nanoparticles were subsequently incorporated into the CIGS layers using the same PLD technique for photodetection applications. Owing to the localized surface plasmon resonance (LSPR) induced by the embedded Au nanoparticles, photon absorption within the CIGS layers was significantly enhanced across the visible and NIR spectral regions. Increasing the film thickness in the presence of Au nanoparticles promoted the formation of larger grains and yielded notable improvements in crystallinity. The dark electrical behavior of plasmonic and non-plasmonic p-CIGS/n-Si heterojunctions was analyzed using the conventional J–V method, as well as the Cheung–Cheung and Norde methods. Key diode parameters, including barrier height, ideality factor, and series resistance, were extracted and comparatively evaluated. Among the studied devices, the Au-CIGS2A heterojunction (based on Au-embedded CIGS thin film produced with 86,400 laser pulses) exhibited the most ideal diode characteristics, whereas the CIGS1A device (based CIGS thin film produced with 43,200 laser pulses) demonstrated the least favorable electrical performance. Under illumination, the combined effect of increased CIGS thickness and the LSPR-driven optical enhancement provided by the Au nanoparticles resulted in higher photovoltaic conversion efficiency in the corresponding heterojunction diodes.

Co-/Cu-co-doped ZnO nanorods are synthesized by electrochemical deposition to investigate the effect of co-doping on their structural, optical, electronic, and electrochemical properties. XRD, Raman, SEM, and photoluminescence analyses reveal that Co/Cu incorporation modifies the ZnO lattice, increases defect-related states, and reduces the band gap from 3.11 to 2.15 eV. Density functional theory calculations further show that Co 3d and Cu 3d states appear near the Fermi level and contribute to the observed band-gap narrowing. Electrochemical measurements indicate that the co-doped nanorods exhibit the lowest charge-transfer resistance and the highest areal capacitance among the samples studied. Together, these results show that Co/Cu co-doping improves charge-transfer kinetics in ZnO nanorods and highlights co-doping as an effective strategy for tuning oxide electrodes for energy-storage applications.

The present study reports a hierarchical supercapacitor electrode that integrates poly(2-aminothiophenol) (P2-ATH) with a cobalt–nickel heterostructure comprising cobalt carbonate hydroxide hydrate (CCHH) and cobalt-nickel oxide (CNO). The hybrid is synthesized by hydrothermal growth of CCHH/CNO nanoneedles, followed by in situ oxidative polymerization of P2-ATH to yield conformal nanoflakes. This interpenetrating architecture furnishes a porous, electrically percolated network that shortens ion-diffusion paths and accelerates electron transport, thereby coupling the redox activity of P2-ATH with the multiple Faradaic sites of the Co–Ni phase. Electrochemical tests in different electrolytes (NaOH, NaCl, and HCl) demonstrate a strong electrolyte dependence, with 0.5 M HCl yielding the best performance. At 0.4 A g⁻¹, the specific capacitance reaches 113.87 F g⁻¹ in HCl, compared with 27.89 F g⁻¹ in NaOH and 7.73 F g⁻¹ in NaCl. In 0.5 M HCl, the electrode delivers an energy density of 5.69 Wh kg⁻¹ at a specific power of 479.7 W kg⁻¹. The results highlight the synergistic interplay between the conductive P2-ATH and the Co–Ni nanoneedle, establishing P2-ATH/CNO-CCHH as a promising platform for high-rate, durable supercapacitors and broader electrochemical energy-storage applications.

Gold nanoparticles were synthesized via surfactant-free laser ablation and incorporated into electrospun bamboo/poly(vinyl alcohol)/chitosan nanofibers for plasmonic photocatalysis. Comprehensive characterization via FE-SEM, FTIR, Raman, TGA, and UV–Vis spectroscopy revealed the synergistic integration of renewable bamboo biocomponents with laser-ablated Au nanoparticles. At pH 10, Bamboo/Au/PVA/CS-2 nanofibers achieved 70.55% methylene blue degradation in 240 min, a 1.8-fold improvement over the PVA/CS baseline (50.27%), with a pseudo-first-order rate constant of 0.0038 min−1. Radical scavenger experiments confirmed that superoxide radicals (∙O₂−) and photogenerated holes (h+) are the dominant reactive species, thereby elucidating the SPR-assisted charge-transfer mechanism. These results demonstrate that bamboo-derived, Au-modified PVA/CS nanofibers represent a promising class of eco-friendly, plasmon-enhanced photocatalysts for sustainable water treatment, establishing an innovative platform for colloid-interface engineering in environmental remediation.

Flexible piezoelectric sensors based on electrospun poly(vinylidene fluoride) (PVDF)/polyacrylonitrile (PAN)/graphene nanofibers were fabricated and evaluated for passive human body motion detection. Optimized electrospinning yielded smooth, continuous fibers with diameters of 200–250 nm and uniform films with thicknesses of 20–25 µm. Fourier transform infrared (FTIR) spectroscopy confirmed a high fraction of the piezoelectrically active β-phase in PVDF, which was further enhanced by post-deposition thermal treatment. Graphene and lithium phosphate were incorporated to improve electrical conductivity, β-phase nucleation, and piezoelectric response, while PAN provided mechanical reinforcement and flexibility. Custom test platforms were developed to simulate low-amplitude mechanical stimuli, including finger bending and pulsatile pressure. Under applied pressures of 40, 80, and 120 mmHg, the sensors generated stable millivolt-level outputs with average peak voltages of 25–30 mV, 53–60 mV, and 80–90 mV, respectively, with good repeatability and an adequate signal-to-noise ratio. These results demonstrate that PVDF/PAN/graphene nanofiber films are promising candidates for flexible, wearable piezoelectric sensors capable of detecting subtle physiological signals, and highlight the critical roles of electrospinning conditions, functional additives, and post-processing treatments in tuning their electromechanical performance.

Although some of the human senses can nowadays be replaced by low-cost electronic sensors such as microphones and image sensors, a compact low-cost electronic nose (E-nose) remains elusive. In this work, an E-nose is presented that can capacitively detect volatile organic compounds (VOCs). The E-nose consists of an array of 1024 capacitive microelectrodes on a complementary metal-oxide-semiconductor (CMOS) chip, functionalized by inkjet printing. The pixels are coated with a UV-curable ink and metal–organic frameworks (MOFs: ZIF-8, MIL-101(Cr), MIL-140A) to create chemically diverse microdomains that generate gas-specific response patterns through adsorption-driven dielectric loading. ZIF-8 exhibits the highest response to 2-butanone, whereas the UV-curable layer responds most strongly to toluene; both show low cross-sensitivity to water vapor, enabling operation under humid conditions. After calibration in pure gases, reproducible responses to controlled binary mixtures of toluene and 2-butanone are observed. The device operates at low power, combines a large 1024-pixel array with CMOS integration, and offers application-specific functionalization by inkjet printing, providing both low cost and versatility. By further extending the range of functionalization materials, the E-nose can be applied to analyze a wide variety of gases, with potential applications in safety monitoring, health, agriculture, and robotics.

In this study, we developed a ternary nanocomposite using graphene oxide (GO), multiwalled carbon nanotubes (MWCNTs), and tungsten trioxide (WO₃), nanostructures, synthesized via a straightforward chemical process with ultrasound assistance. The initial composition was GO/MWCNT, later combined with WO₃ to form the GO/MWCNT: WO₃ (25/25:50) structure. Characterization was performed using X-ray diffraction, which revealed the multiphase nature of the WO₃ nanostructures. Scanning Electron Microscopy showed the one-dimensional CNTs interwoven with graphene oxide sheets decorated with densely populated WO₃ nanopetals. Fourier transform infrared and Raman spectroscopy confirmed the chemical composition of the system. The photocatalytic degradation of Rhodamine-B in water under visible light irradiation was significantly enhanced using the GO/MWCNT: WO₃ nanocomposite, achieving an 85 % degradation rate compared to only 10 % by GO alone, highlighting its potential for environmental remediation.

In the present work, an essential advance in the preparation of novel nanocomposites based on functionalized V₂O₅ nanostructures with reduced graphene oxide by hydrothermal method, which has great potential for use in photocatalytic processes related to environmental remediation. XRD analysis confirmed V₂O₅ in an orthorhombic structure. SEM images showed transparent RGO layers well anchored onto the surface of the V₂O₅ with a homogeneous distribution. Raman spectroscopy further explained the hybridization and interaction between the components. The photocatalytic activity of Rhodamine-B in aqueous solutions has been studied upon irradiation with visible light. A high RhB degradation was obtained using the V₂O₅/RGO photocatalyst (82 %), compared to the degradation obtained with only V₂O₅ (60 %). First-principles Density Functional Theory (DFT) simulations reveal a strong interaction between V₂O₅ molecules and graphene surfaces, with an adsorption energy of −1.673 eV and a significant charge transfer of 0.367 e− to RGO. This interaction modifies the electronic structure, creating semi-metallic behavior near the Fermi level and enhancing catalytic activity through improved charge carrier dynamics and active sites for photocatalytic applications.

Thin films of Cu2Sn1−xGdxS3 were prepared on soda-lime glass substrates using spin coating in a sulfur-rich environment. We investigated how doping Cu2SnS3 with gadolinium (Gd) affected its structural, morphological, and optical properties using X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), and UV-Vis spectroscopy. XRD showed that all samples had a polycrystalline monoclinic structure, while FE-SEM revealed a mix of spherical and polygon-shaped grains. Optical analysis indicated an energy gap ranging from 2.10 to 1.50 eV, increasing with higher Gd content. The films exhibited increasing transmittance with longer wavelengths in the UV-Vis region. When tested for photocatalytic activity, the Cu2Sn1−xGdxS3 films effectively degraded methylene blue (MB) dye under visible light within 220 minutes. The Cu2Sn0.25Gd0.75S3 film showed the highest degradation efficiency (90.77%) with a rate constant (k) of 0.093 min−1. Adjusting the pH of the dye solution improved the performance, reaching 90.77% degradation efficiency at pH 10, compared to 41.25% and 61.94% at pH 4 and 7, respectively. Tests with scavengers EDTA-Na, IPA, and BQ resulted in degradation efficiencies of 61.78%, 78.24%, and 43.56%, respectively, highlighting that the highest efficiency (90.77%) occurred without scavengers. The results show promising potential for these films in treating pollutants in industrial and domestic wastewater systems.

The novel design of gold/polypyrrole-multi-walled carbon nanotubes/titanium dioxide/aluminum oxide/P-type silicon/aluminum (Au/PPy-MWCNTs/TiO2/Al2O3/p-Si/Al) is utilized to fabricate supercapacitors, sensors, diodes, and microelectronic devices. The electrical characteristics of the structure are examined both in the dark and under illumination to evaluate its photosensing performance. The real part of the AC conductivity at all voltages and temperatures is observed to be low at low- and mid-frequencies but significantly increases at high frequencies. The imaginary part of the AC conductivity exhibits three distinct behaviors: it is positive at low frequencies and shows both negative and positive values at high frequencies. At specific temperatures, such as 293, 273, and 253 K, the imaginary component of the AC conductivity (σ ac) is negative only at high frequencies. In the Cole-Cole diagrams, the symmetrical semicircles increase with temperature for all voltages, except at V = -2 V. The real part of the electric modulus (M′) shows positive and negative values; however, at certain temperatures, it is positive. The imaginary part of the modulus (M″) is consistently positive.

This study reports the synthesis of a nanohybrid material composed of poly(2-methylaniline) (P(2MA)) and iron oxide (Fe2O3) as electrodes for supercapacitors using a simple and cost-effective method. Various characterization techniques were employed to analyze the samples. The results revealed that the Fe2O3/P(2MA) nanohybrid exhibits nanofiber structures, while pure P(2MA) displays a porous hollow sphere morphology. Furthermore, the analysis confirmed the effective dispersion of Fe2O3 nanoparticles within the polymer matrix. The electrochemical properties of the Fe2O3/P(2MA) nanohybrid were found to surpass those of pure P(2MA) in both NaCl and HCl electrolytes. Notably, the nanohybrid demonstrated longer discharge times and higher oxidation/reduction currents in HCl than NaCl. The gravimetric and areal capacitances were measured at 998.4 F g−1 and 1497.6 mF cm−2 in 0.5 M HCl at a current density of 0.6 A g−1. Furthermore, the nanohybrid retained 99.9% of its initial specific capacitance after 2,000 cycles. These findings underscore the significant potential of the Fe2O3/P(2MA) nanohybrid as a high-performance supercapacitor electrode for energy storage applications.

The effect of the Gd/Sn composition ratio of Cu₂Sn_1-xGd_xS₃ is examined. The films are fabricated on glass substrates in a sulfur atmosphere via the spin coating. The influence of the Gd/Sn composition ratio on the structural, morphological, optical, and electrical properties of the films is investigated using X-ray diffraction, FESEM, UV-Vis, and Hall effect. XRD patterns for the films revealed that all films have a monoclinic polycrystalline. The morphological and optical properties of the films show the formation of spherical grains and polygonal structures with an energy band in the range of 2.10–1.50 eV. The electrical properties of the films are changed by increasing the Gd/Sn composition ratio in the film. Furthermore, the Cu₂Sn_1-xGd_xS₃/CdS heterojunction solar cell was modeled by SCAPS-1D. The optimized conditions yielded exceptional photovoltaic parameters, achieving an open-circuit voltage of 0.7885 V, short circuit current density of 41.09 mA/cm², fill factor of 85.30%, and an efficiency of 27.3%.

Lead-free halide perovskite, kesterite, and delafossite semiconductors were integrated into a multilayer ternary heterostructure (Cs₂ SnCl₆ /Cu₂ ZnSnS₄ /CuFeO₂) to enable direct solar-driven hydrogen production from sewage water. X-ray photoelectron spectroscopy confirms the expected elemental composition and oxidation states, while X-ray diffraction verifies the successful incorporation of all three layers with well-defined crystallinity. Optical measurements reveal a systematic narrowing of the effective band gap, decreasing from 1.73 eV for CuFeO₂ to 1.50 eV for the Cu₂ ZnSnS₄ /CuFeO₂ bilayer and further to 1.12 eV for the complete Cs₂ SnCl₆ /Cu₂ ZnSnS₄ /CuFeO₂ stack. The multilayered architecture enabled effective charge separation and transport, delivering a photocurrent density of −24.0 mA cm-2, approximately 77 times higher than the dark current density. The incident photon-to-current efficiency reaches 77%. These results demonstrate strong photoresponsivity and confirm the suitability of the multilayer heterojunction for efficient solar-driven hydrogen production. The extracted thermodynamic parameters (ΔH* = 3.452 kJ mol⁻¹ and ΔS* = 9.644 J mol⁻¹ K⁻¹) indicate a low activation barrier for interfacial charge transfer, suggesting that the system effectively couples photonic and thermal contributions to enhance hydrogen-evolution kinetics. Collectively, these findings establish the all-lead-free Cs₂ SnCl₆ /Cu₂ ZnSnS₄ /CuFeO₂ heterostructure as a highly efficient photoelectrode for solar-to-hydrogen conversion in complex wastewater environments. Demonstrating hydrogen evolution directly from sewage water further highlights the dual functionality of this architecture for simultaneous wastewater valorization and sustainable fuel production.

UV sensors hold significant promise for various applications in both military and civilian domains. However, achieving exceptional detectivity, responsivity, and rapid rise/decay times remains a notable challenge. In this study, we address this challenge by investigating the photodetection properties of CdS thin films and the influence of surface-deposited gold nanoparticles (AuNPs) on their performance. CdS thin films were produced using the pulsed laser deposition (PLD) technique on glass substrates, with CdS layers at a 100, 150, and 200 nm thickness. Extensive characterization was performed to evaluate the thin films’ structural, morphological, and optical properties. Photodetector devices based on CdS and AuNPs/CdS films were fabricated, and their performance parameters were evaluated under 365 nm light illumination. Our findings demonstrated that reducing CdS layer thickness enhanced performance concerning detectivity, responsivity, external quantum efficiency (EQE), and photocurrent gain. Furthermore, AuNP deposition on the surface of CdS films exhibited a substantial influence, especially on devices with thinner CdS layers. Among the configurations, AuNPs/CdS(100 nm) demonstrated the highest values in all evaluated parameters, including detectivity (1.1×1012 Jones), responsivity (13.86 A/W), EQE (47.2%), and photocurrent gain (9.2).

By using DFT simulations employing the GGA/PBE and LDA/CA-PZ approximations, the effects of the Hubbard U correction on the crystal structure, electronic properties, and chemical bands of the cubic phase (Pm3̲m) of STO were investigated. Our findings showed that the cubic phase (Pm3̲m) STO’s band gaps and lattice parameters/volume are in reasonably good accordance with the experimental data, supporting the accuracy of our model. By applying the DFT + U method, we were able to obtain band gaps that were in reasonably good agreement with the most widely used experimental band gaps of the cubic (Pm3̲m) phase of STO, which are 3.20 eV, 3.24 eV, and 3.25 eV. This proves that the Hubbard U correction can overcome the underestimation of the band gaps induced by both GGA/PBE and LDA/CA-PZ approximations. On the other hand, the Sr-O and Ti-O bindings appear predominantly ionic and covalent, respectively, based on the effective valence charges, electron density distribution, and partial density of states analyses. In an attempt to enhance the performance of STO for new applications, these results might also be utilized as theoretical guidance, benefitting from our precise predicted values of the gap energies of the cubic phase (Pm3̲m).

The use of waste materials has gained attention as a sustainable approach in various industries. Cigarette waste, which is typically discarded as a non-recyclable material, poses a significant environmental challenge due to its toxicity and slow decomposition rate. However, by incorporating this waste into ceramic bricks, new approaches for waste management and resource utilization are explored. This research work provides a detailed evaluation of the possibility of utilizing natural zeolite tuff incorporated with cigarette waste to produce sustainable ceramic bricks. Uniform powders are produced by milling various combinations of zeolitic tuff and cigarette waste using a planetary ball mill. The substitution ratios ranged from 0% to 12% by weight of the zeolitic tuff, with increments of 2%. Ceramic discs were formed by dry pressing and then subjected to sintering at different heat treatment temperatures (950–1250 °C). The impact of the inclusion of cigarette waste on the microstructural and technical features of zeolite tuff-based ceramic bricks has been thoroughly investigated. The results of the experiments demonstrate that incorporating cigarette waste into the development of ceramic bricks leads to improved thermal insulation properties, with thermal conductivity ranging from 0.33 to 0.93 W/m·K. Additionally, these bricks exhibit a lighter weight in a range of 1.45 to 1.96 g/cm3. Although the inclusion of cigarette waste slightly reduces the compressive strength, with values ranging from 6.96 to 58.6 MPa, it still falls within the acceptable range specified by standards. The inclusion of cigarette waste into zeolite tuff is an innovative approach and sustainable practice for reducing energy consumption in buildings while simultaneously addressing the issue of waste disposal and pollution mitigation.

The current work presents the possibility of tuning the dielectric parameters by changing the temperature, voltage, and frequency. The unusual behavior of some parameters was attributed to the lattice mismatch constant between gallium arsenide (GaAs) and silicon (Si) and the crystal defects between them. In this article, a thin GaAs film has been grown on Si substrates by liquid phase epitaxial (LPE) as n-GaAs/p-Si heterostructure. Despite the lattice mismatch between GaAs and Si, our interest in this article was focused on investigating the electrical and dielectric properties by I-V and C-V measurements. This was distinguished in the behavior of the dielectric properties such as the imaginary part of modules M″, the real and imaginary part of electrical conductivity σ^′ac and σ^″ac, respectively, which has not been seen before at high frequencies.

In this groundbreaking study, we unveil the remarkable structural, electronic, and optical Properties of the newly discovered double perovskite material, K₂AgBiI₆, presenting a paradigm shift in materials science. The unique crystal structure and diverse atomic interactions inherent in this double perovskite make it an up-and-coming candidate for various technological applications, particularly in photovoltaics; owing to its stability and resistance to heat and humidity, we aim to shed light on the extraordinary potential of K₂AgBiI₆. Our study provides valuable insights for researchers engaged in tailored material design. We anticipate that the exceptional electronic properties of K₂AgBiI₆ will not only redefine the boundaries of materials engineering but also catalyze unprecedented advances in sustainable technology. Employing the powerful computational tool CASTEP, we conducted detailed electronic structure calculations within the framework of Density Functional Theory (DFT) to unravel the electronic properties of the double perovskite K₂AgBiI₆. Our investigation thoroughly explored structural properties, band structure, total density of states (DOS), and partial density of states (PDOS). Furthermore, we systematically examined the influence of different exchange-correlation functionals, including LDA, GGA, and m-GGA, on the electronic and optical features of the material by presenting a comparative analysis of these approximations.

This study introduces the development of novel, flexible gas sensors operating at room temperature (RT), utilizing a graphene oxide (GO) via the modified Hummers' method and bacterial nanocellulose (BNC) composite to enhance gas detection in industrial and environmental settings. The composite materials, denoted as GO@BNC, were synthesized with varying GO concentrations ranging from 2 % to 30 %, aiming to investigate their responsiveness to gases such as carbon dioxide (CO₂), oxygen (O₂), acetone (Ac), and ethanol (Eth). The prepared nanomaterials were characterized using FT-IR, Raman, TGA, SEM, and AFM techniques. The bandgap of Go ranges from 4.19, 3.47, 3.16, 2.79, and 2.48 eV for 2, 5, 10, 20, and 30 % GO concentrations, respectively. Notably, the sensor containing wt % of 20 % GO concentration exhibited remarkable sensitivity to Ac, achieving a 270 % increase in resistance at a concentration of 250 μL/L. Conversely, the sensor with a wt % of 30 % GO composition showed superior sensitivity to Eth, with a 420 % signal enhancement under similar conditions. Further modification of GO@BNC through mild reduction resulted in the formation of reduced graphene oxide (rGO@BNC) composites intended to assess the functional groups' impact on sensing performance. Our findings underscore the potential of GO@BNC composites as sustainable and efficient materials for fabricating eco-friendly flexible gas sensors and devices for detecting organic compounds.