Search Results (2,194)

This study investigates the atmospheric corrosion behavior of high-lead bronze alloys within a simulated aggressive environment characterized by high humidity, acidity, chlorides, oxygen, and CO₂. The evolution of surface morphology and corrosion products was systematically monitored using colorimetric analysis and micro-Raman spectroscopy. Results indicate that the initial patina primarily comprised cuprite (Cu₂O) and cassiterite (SnO₂), which are predominantly benign phases. During the early corrosion stage, lead oxidation and carbonation prevailed, generating abundant bright-white cerussite. Subsequently, as copper-driven corrosion became dominant, these white deposits diminished and were progressively replaced by characteristic green “bronze disease”, identified as atacamite (Cu₂(OH)₃Cl). The findings reveal that preferential lead corrosion is likely to induce localized pitting, thereby accelerating degradation of the copper substrate. Consequently, higher lead content may reduce the overall corrosion resistance of bronze artifacts under these specific conditions. These results offer experimental insights into atmospheric corrosion mechanisms and inform the development of evidence-based conservation strategies for bronze cultural heritage. Full article

Zn–Sn–O (ZTO) thin-film transistors (TFTs) are promising indium-free oxide semiconductor devices, but their electrical stability is limited by oxygen-related defect states. In this study, Ga and Si incorporated ZTO TFTs were systematically compared using an identical bottom-gate top-contact device architecture to investigate dopant-dependent defect modulation and bias-temperature stability. Both Ga and Si incorporation induced a positive threshold-voltage shift and reduced the relative contribution of oxygen-deficient bonding components, suggesting modification of oxygen-related defect environments in the ZTO channel. Optical analysis further showed reduced Urbach energies after dopant incorporation, suggesting a decrease in localized band tail states and reduced structural disorder. Under negative bias temperature stress (NBTS), SZTO exhibited the smallest threshold-voltage shift, demonstrating the most effective stability enhancement. These results indicate that Ga incorporation preserves high field-effect mobility while improving stability, whereas Si incorporation more effectively reduces oxygen-related defect features and provides enhanced NBTS stability. This study provides insight into the dopant-dependent defect engineering for the improved reliability of indium free oxide TFTS. Full article

Ag-SnO₂ composites are widely adopted as electrical contact materials in low-voltage apparatuses. Ongoing upgrades of electrical devices impose higher standards for their mechanical strength, machinability, and electrical conductivity, among which the SnO₂ volume fraction is a dominant factor regulating material performance. In this work, Ag-SnO₂ electrical contact composites are reinforced with 15 μm SnO₂ particles at various volume fractions. Increasing SnO₂ volume fractions can improve the hardness. The ultimate tensile strength reaches a maximum value of 219.1 MPa at the SnO₂ volume fraction of 18.3 vol%. Excessively high SnO₂ content (26.5 vol%) leads to the brittle fracture of the composite and a sharp decline in tensile strength. Indirect strengthening dominates the overall mechanical performance, among which grain refinement serves as the primary strengthening mechanism, followed by dislocation multiplication strengthening, while the Orowan looping effect is negligible for coarse 15 μm SnO₂ particles. This work clarifies the microstructure–performance correlation and strengthening mechanism of particle-reinforced Ag-SnO₂ composites, providing a theoretical and experimental basis for the optimal design and performance optimization of high-performance electrical contact materials. Full article

Strict monitoring of methane (CH₄) during underground coal mining is necessary, as the lower explosive limit (LEL) is 5 vol% in air. A conventional tin oxide (SnO₂)-based metal–oxide semiconductor (MOS) sensor has an operating temperature of 200–400 °C, which requires a prohibitive power demand and entails the risk of ignition within an intrinsically safe environment. The decoration of SnO₂ nanoarchitectures with palladium has been demonstrated to achieve room temperature (RT) detection of CH₄ due to the chemical sensitisation spillover mechanism and electronic sensitisation by Schottky barrier modulation. Moreover, palladisation of SnO₂ nanowires (NWs) is likely to be an effective route for achieving a more efficient detection of CH₄ aerosol at RT or near RT. The purpose of this mini-review is to provide a critical synthesis of advances that have been reported between 2020 and 2026. Because no published study to date has directly demonstrated room-temperature CH₄ detection using pure Pd-decorated SnO₂ nanowires, performance data from mechanistically analogous systems—namely H₂-sensing Pd–SnO₂ nanowires and CH₄-sensing non-nanowire Pd–SnO₂ nanostructures—are included in this review and are explicitly labelled as such throughout. This absence of direct RT CH₄ NW data constitutes the primary research gap motivating this review. The performance of Pd-containing SnO₂ nanostructures reported in the literature spans response values of 17.6 (300 ppm CH₄, 2.5 mol% Pd–SnO₂ nanoporous, 340 °C) to 21.3 (3000 ppm CH₄, bimetallic Pt–Pd–SnO₂ mesoporous, 400 °C), representing a 3–10× improvement over bare SnO₂ (response: 2–10 in the same concentration range). These benchmarks were obtained at elevated temperatures (340–400 °C); no equivalent room-temperature CH₄ detection data for Pd–SnO₂ nanowires currently exists in the published literature. Reported response times range from 3 to 9 s at elevated temperature (340–400 °C) to 74–78 s for room-temperature visible-light-activated systems, where photocatalytic oxygen activation is the rate-limiting step. The 30 s MSHA alarm threshold is met by elevated-temperature systems but remains a challenge for RT configurations. The LODs were 175.9 ppb (bimetallic PdxPt/SnO₂ mesoporous system). Two hybrid composites containing rGO exhibited an extended capability for RT operation. Bimetallic PdPt decoration and ML-augmented sensor arrays are identified as the most promising near-term pathways to bridge the selectivity and stability gaps for certified mining deployment. Full article

ZnO is widely used as an electron transport layer in quantum-dot light-emitting diodes (QLEDs) because of its high electron mobility and suitable energy levels. However, rapid electron transport may cause excessive electron injection, leading to charge accumulation and parasitic recombination. SnO₂ provides weaker electron transport, but using it alone limits device performance. Here, a SnO₂/ZnO bilayer electron transport layer was introduced to regulate electron injection. Unlike previously reported structures in which SnO₂ directly contacts the QDs, the present configuration places SnO₂ on ITO and ZnO adjacent to the QD layer. The low-concentration ZnO overlayer reduced the RMS roughness of the SnO₂ film from 1.79 to 1.07 nm and facilitated electron injection, while the underlying SnO₂ layer moderated the electron supply. The bilayer also suppressed leakage current and showed the lowest capacitance peak, consistent with improved charge balance. The bilayer QLED achieved a maximum current efficiency of 13.40 cd/A and a maximum luminance of 33,210 cd/m². Its current efficiency was 100% and 32.7% higher than those of the SnO₂ and ZnO devices, respectively. These results demonstrate that the bilayer improves charge balance through facilitated electron injection and controlled electron supply. Full article

Hydrogen-bond organization plays a central role in determining the structure and properties of water from molecular to macroscopic scales. In this study, we propose a geometry-based descriptor for small hydrogen-bonded water clusters, (H₂O)_n, with n = 2–6. The central element of the proposed geometric framework is the dimensionless geometric index, S_n = d/l, where d is the center-to-molecule distance in a cluster configuration and l is the nearest-neighbor O···O distance associated with hydrogen-bonded water molecules. The geometric descriptor is not intended to replace quantum-chemical calculations or to provide a direct measurement of hydrogen-bond energy, lifetime, or number. Instead, it provides a compact geometric framework for describing the structural organization of small hydrogen-bonded water clusters. The obtained geometric trend is compared with selected Nuclear Magnetic Resonance (NMR), Møller–Plesset perturbation theory (MP2), and radial distribution function data as complementary qualitative and semi-quantitative references. The proposed geometric index S_n = ${\displaystyle \frac{d}{l}}$ was further compared with MP2 quantum-chemical O···O distances for (H₂O)_n clusters, n = 2–6, using the oxygen atoms as structural nodes of the hydrogen-bonded motifs. This comparison showed that the exponential increase in S_n is consistent with the characteristic O···O donor–acceptor length scale of approximately 2.8 Å, linking the geometric framework with calculated molecular geometries. Over the limited interval n = 2–6, the geometric index Sn increases monotonically and nonlinearly with cluster size. The quantum-chemical reference data previously reported in our study, comprising GIAO-DFT-calculated ¹H chemical shifts obtained for MP2-optimized water-cluster geometries, show a rapid nonlinear increase from the dimer to the pentamer, followed by the onset of saturation in the pentamer–hexamer range. The semi-empirical stabilization parameter evaluated in the present study indicates increasing relative stabilization, with a reduced incremental change around n ≈ 4–5. The qualitative consistency of these size-dependent trends supports the use of Sn as a compact geometric descriptor of hydrogen-bond organization in small water clusters, without interpreting it as a direct quantitative measure or mechanistic framework of hydrogen-bond cooperativity. Importantly, liquid water is not treated as a system of closed cyclic clusters; cyclic motifs are used only as frameworked geometric reference configurations for small hydrogen-bonded aggregates. The geometric trend is qualitatively compared with selected quantum-chemical, spectroscopic, and radial distribution function data and should be regarded as an empirical geometric approximation over the limited interval n = 2–6. These findings indicate that geometric, spectroscopic, and quantum-chemical descriptors reflect related, but not identical, aspects of hydrogen-bond organization. The proposed approach links cluster geometry, O···O intermolecular distances, and hydrogen-bond connectivity in a simplified geometric description. Full article

The rise in the need for sustainable energy has facilitated the advancement of perovskite solar cells (PSCs) as potential substitutes for traditional photovoltaic technologies. Nevertheless, their performance is very sensitive to environmental factors, especially temperature, which influences the charge transport and recombination processes. This paper examines the thermal effect on the electrical characteristics and impedance response of lead-free PSCs in accordance with the FTO/ETL (C₆₀, PCBM, SnS₂, ZnSe)/CH₃NH₃SnBr₃/Cu₂O configuration. The experiments were performed with SCAPS-1D under usual illumination, using a combination of current-voltage analysis and impedance spectroscopy between 270 and 400 K. The findings indicate that there is a significant reduction in open-circuit voltage with higher temperature, whereas the short-circuit current density does not change much. The enhancement of the fill factor increases and then decreases with increased temperature, leading to a net decrease in power conversion efficiency because of the increased recombination. The impedance analysis is also an indicator of lower recombination resistance and accelerated charge carrier dynamics. These results demonstrate that thermal control and interface optimization can be important for enhancing PSC performance. Full article

The Earth’s environment is deteriorating, and biodiversity is declining. The use of plant-based cellulose nanofibers (CNFs) as structural materials can reduce environmental impact, and further technological developments are anticipated. This review article introduces types of cellulose derived from wood, weeds, bamboo, and fruits, and examines the potential technological applications of CNFs. It is hypothesized that maintaining an appropriate content of Mn, Ca, and O—including the interactions of Ca within carbon-based structures—could contribute to plant health, while the exclusion of elements such as V, Cd, and Sn (regardless of the effectiveness of partial sequestration) could promote cell activity. Calcium deposition can influence wood growth depending on the elemental composition in the bark, and a hypothesis regarding pH adjustment for shoot formation is proposed (see textbook on inorganic chemistry). Furthermore, manufacturing processes for CNFs and their mechanical properties—including evaluation methods—are summarized. This overview focuses on nanostructures that exhibit heterogeneous functional and mechanical properties and offer potential benefits in reducing environmental impact through processes such as 3D printing and coating. CNFs derived from fruit peels can yield lightweight and durable materials. Furthermore, the roles of proteins and fruit-derived components in neutralizing acidic environments and reducing oxides are discussed. A concept is proposed that links the processing of fruit-peel-based materials with environmental applications such as forest restoration and combating desertification. The hypothesis is put forward that cytoplasmic activity and cell wall strengthening could be enhanced through chlorophyll-related processes and water transport mechanisms. Optimizing pH conditions could promote shoot formation in plants such as conifers. Sustainable greening can be achieved through the use of cellulose-based materials in combination with water-retaining components such as bamboo-derived resources. The interaction between CNFs, plant bark, and water-bound proteins can contribute to forest regeneration and the curbing of slash-and-burn practices. Overall, this approach can contribute to environmental remediation, the reduction of environmental impact, and urban greening in degraded regions. Full article

To improve the corrosion resistance of Sn coatings on Cu substrates in chloride-containing environments, pure Sn and Sn–P coatings containing 0.02, 0.05, and 0.08 wt.% P were prepared by hot-dip coating. Their surface morphology, surface-film chemistry, and corrosion behavior were characterized using electrochemical measurements, atomic force microscopy (AFM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), and X-ray photoelectron spectroscopy (XPS). The results demonstrate that trace phosphorus addition enhances the electrochemical stability of Sn coatings prepared via the hot-dip method. The corrosion current density decreased from 1.55 × 10⁻⁶ A·cm⁻² for pure Sn to 3.28 × 10⁻⁷ A·cm⁻² for SnP0.02, corresponding to a reduction of approximately 79%. Meanwhile, the total resistance increased from 10.46 to 19.03 kΩ·cm², confirming the enhanced barrier effect of the surface film. AFM results showed that the surface roughness Ra decreased from 13.41 nm for pure Sn to 8.72–12.69 nm for the Sn–P coatings. XPS identified Sn–O, P–O, and Sn–P species, suggesting the formation of a Sn–O/P–O-containing protective film. SnP0.02 exhibited the best overall corrosion resistance, whereas excessive P promoted local P-rich regions and non-uniform film formation, limiting further improvement. Full article

In the present work, graphene-modified zinc oxide (ZnO-rGO) and fluorine-doped tin oxide (FTO) thin films were successfully fabricated using a simple, low-cost pulsed spray pyrolysis technique. The structural, morphological, optical, electrical, and surface electronic properties of the deposited films were systematically characterized. X-ray diffraction (XRD) analysis confirmed the formation of polycrystalline ZnO- and SnO₂-based phases with crystallite sizes in the nanometer range. The crystallographic parameters, microstrain, and dislocation density of the deposited films were found to be influenced by the incorporation of reduced graphene oxide (rGO) and fluorine dopants. Scanning electron microscopy (SEM) revealed compact and homogeneous surface morphologies with good film coverage and well-defined nanocrystalline features. Optical characterization demonstrated the wide-bandgap semiconducting behavior of the deposited films, with optical bandgap energies ranging from 3.262 to 3.312 eV for the ZnO-rGO films and from 3.91 to 4.01 eV for the FTO films. Kelvin probe measurements yielded work-function values in the range of approximately 5.0–5.2 eV, indicating favorable surface electronic characteristics suitable for optoelectronic applications. Furthermore, fluorine incorporation enhanced the dielectric response of the SnO₂ films, particularly in the low-frequency region owing to increased interfacial polarization effects. The obtained results demonstrate that pulsed spray pyrolysis provides a simple, cost-effective, and efficient route for fabricating ZnO-rGO and FTO thin films with desirable structural, optical, electrical, and surface electronic properties. These findings highlight the considerable potential of the developed materials for transparent electrodes and a wide range of optoelectronic applications. Full article

In semiconductor photocatalysis, the strong redox ability of a wide band gap and the broad light absorption range of a narrow band gap are a pair of irreconcilable trade-offs. By combining semiconductors with different band gap widths and band edge positions, both of these advantages can be achieved simultaneously. A ternary Cu₂O-SnO₂/g-C₃N₄ (CuSnCN) composite photocatalyst was prepared through the hydrothermal and calcination method. Structural analyses confirm the successful integration of truncated octahedral Cu₂O, spherical SnO₂, and layered g-C₃N₄, which extends the visible-light response to 650 nm. The optimized system achieves a remarkable 96.58% degradation of methyl orange (80 min, 0.2 g/L catalyst, pH = 3) through dual heterojunction synergies: p–n junctions (Cu₂O/g-C₃N₄ and SnO₂/g-C₃N₄) and Z-scheme charge transfer (SnO₂/Cu₂O), with •O₂⁻/h⁺ identified as the dominant reactive species. This work establishes a tunable heterojunction platform for the elimination of multiple pollutants through engineered radical-generation pathways. Full article

Spray pyrolysis is a popular method for the low-cost synthesis of oxides and other compounds in thin-film form. Here, we discuss several nuances of using this method for ternary and quaternary compounds. Specifically, we outline how precursor solubility and thermal decomposition, as well as desorption of intermediate species from the sample surface govern the spray pyrolysis growth process. We demonstrate how the stoichiometry transfer from solution to film can be affected in selected test cases. We present real-time optical growth measurements of the behaviour of individual Cu, Cr, Zn, and Sn precursors, as well as post-growth analysis of film composition by X-ray photoelectron spectroscopy for ternary transparent conducting oxides (TCOs; p-type: Cu_xCrO₂, SnTiO_x; and n-type: a-ZnSnO₃). We illustrate how several steps of spray pyrolysis affect the stoichiometry transfer from the solution to the ternary thin film. Using binary Cu₂O as a test case, we also show how the choice of instrument geometry and nozzle type can affect film homogeneity. All materials discussed have been chosen to highlight potential difficulties of the spray pyrolysis process of ternary, quaternary, or even more complex oxides, and the mechanisms should be considered for other materials as well. We therefore also provide an extensive overview of suitable precursor salts with similar expected properties as used in this experimental work to guide future ternary oxide studies. Full article

This study explores the performance of an ultrathin Cu₂ZnSnSe₄ (CZTSe) absorber-based solar cell using numerical simulations carried out with SCAPS-1D software (version 3.8). Ultrathin absorber layers, generally thinner than 500 nm, are attractive because they require less material, reduce manufacturing costs, and can improve carrier collection due to the shorter distance that charge carriers must travel. However, when the absorber layer becomes very thin, it cannot absorb enough photons, which may limit the overall device performance. To overcome this challenge, the use of back surface field (BSF) layers is examined as a practical approach to improve photovoltaic efficiency. In this work, a solar cell structure composed of Carbon/BSF/CZTSe/CdS/i-ZnO/ITO was designed and simulated, with the thickness of the CZTSe absorber layer kept constant at 85 nm. Three different p⁺-type BSF materials, V₂O₅, Sb₂S₃, and CuSCN, were studied to understand how they influence device behavior. Important parameters such as electron affinity, interface defect density, acceptor defect density in the absorber layer, recombination processes, back contact properties, and operating temperature were systematically investigated. The addition of BSF layers forms a strong electric field at the p⁺–p interface, which helps push minority carriers toward the depletion region and reduces recombination losses at the back contact. The simulation results show that selecting a suitable BSF material can significantly enhance charge carrier collection and improve the efficiency of ultrathin CZTSe solar cells, offering useful guidance for designing more efficient thin-film photovoltaic devices. Full article

In this study, an electrochemical immunosensor based on polyaniline/nano-Fe₃O₄ (PANI/Nano-Fe₃O₄) nanocomposite (PANI/Nano-Fe₃O₄/Anti-FLA/BSA/GCE) was developed for the highly sensitive and selective detection of trace levels of fluoranthene (FLA) in marine environments. Fluoranthene antibodies (Anti-FLA) were covalently immobilized on a glassy carbon electrode (GCE) modified with PANI/Nano-Fe₃O₄ via an EDC/NHS activation strategy, enabling specific recognition of FLA based on the antigen–antibody binding mechanism. The performance of the sensor was systematically optimized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV). The results demonstrated a linear inverse relationship between peak current (I_p) and FLA concentration in the range of 0.5~80 ng/mL, with a regression equation of I = −1.55C + 174.602 (R² = 0.996). The limit of detection (LOD) was as low as 0.354 ng/mL (S/N = 3). In real seawater sample analysis, spiked recovery tests at three representative sites in the Maowei Sea, Guangxi, yielded recoveries of 95.44%~97.51%, with RSDs below 3%, confirming the sensor’s resistance to matrix interference. The synergistic effect of the porous conductive network of PANI and the high specific surface area of Nano-Fe₃O₄ significantly amplified the electrochemical signal, while the molecular specificity of the antibody ensured targeted recognition. This sensor provides a novel and effective approach for the on-site rapid detection of polycyclic aromatic hydrocarbon (PAH) pollutants in complex marine environments, offering both high sensitivity and selectivity. Full article

Phosphate ($\mathrm{P}{\mathrm{O}}_4^{3-}$) discharge from municipal wastewater is a major contributor to eutrophication, highlighting the need for efficient treatment technologies that enable both phosphorus (P) removal and potential reuse. In this study, tin (Sn)- and calcium (Ca)-based coagulants, and their composites with chitosan (CS) (CS@Sn, CS@Ca, CS@Sn/Ca), were developed and evaluated for $\mathrm{P}{\mathrm{O}}_4^{3-}$ removal and tentative recovery from both aqueous solutions and municipal wastewater. Among the tested materials, ${\mathrm{SnCl}}_4$ exhibited the highest performance, achieving 97.2–100% $\mathrm{P}{\mathrm{O}}_4^{3-}$ removal over a wide pH range and at low dosages, demonstrating its high affinity toward $\mathrm{P}{\mathrm{O}}_4^{3-}$. The CS@Sn composite material demonstrated satisfactory efficiency, while the Ca-based coagulants exhibited lower efficiency and greater sensitivity to solution chemistry. CaO achieved maximum phosphate removal of 89% under neutral to alkaline conditions, but its efficiency decreased significantly under acidic conditions. CS@Ca and CS@Sn/Ca composites exhibited only moderate removal efficiencies under all experimental conditions tested. SEM and FTIR analyses indicated that $\mathrm{P}{\mathrm{O}}_4^{3-}$ removal occurred through interactions with hydrolyzed Sn(IV) species. The recovered phosphate-rich residues were subsequently subjected to a preliminary pot experiment using lettuce (Lactuca sativa) to explore their potential for agricultural reuse. The results provided an initial indication that some recovered residues may support early plant growth, although further agronomic evaluation under controlled conditions is required. Therefore, ${\mathrm{S}\mathrm{n}\mathrm{C}\mathrm{l}}_4$ represents a promising approach for simultaneous phosphate removal and potential recovery, while the preliminary plant cultivation results indicate potential for agricultural reuse of the recovered residues, warranting further investigation. Full article