Search Results (410)

Sn-polymetallic deposits in the Southern Great Xing’an Range (SGXR) are typically marked by the coexistence of Sn, Cu, Pb, Zn, and Ag, yet the mechanisms controlling their paragenesis and separation remain poorly constrained. The Hujiadian deposit hosts Sn, Cu, Pb, Zn, and Ag mineralization that occurs both as intergrown assemblages within individual orebodies and as distinct but spatially associated orebodies, making it an ideal natural laboratory to investigate element coexistence and fractionation. Three hydrothermal stages are identified: pyrite + cassiterite ± chalcopyrite + quartz + chlorite (Stage I); chalcopyrite + sphalerite ± galena + quartz + fluorite + chlorite ± amphibole ± epidote (Stage II); and sphalerite + galena + pyrite + quartz + chlorite + calcite (Stage III). The rhyolite porphyry yields a zircon U–Pb age of 132.3 ± 2.4 Ma, whereas the Sn ores yield cassiterite U–Pb ages of 129.9 ± 1.3 to 131.4 ± 0.8 Ma. These overlapping ages, within analytical uncertainties, constrain the Sn mineralization to the Early Cretaceous. The rhyolite porphyry is geochemically characterized by a peraluminous, high-K calc-alkaline affinity, coupled with elevated SiO₂ and alkali contents, strong negative Eu anomalies, and low fO₂ (ΔFMQ = −4.9 to 1.1). Collectively, these features are consistent with extensive fractionation under reducing conditions, which would have facilitated Sn accumulation in the residual melt. Pervasive chlorite in the deposit records the physicochemical evolution of the hydrothermal system; four chlorite generations document a shift from early acidic conditions during Sn mineralization to near-neutral or weakly alkaline conditions during late Pb–Zn precipitation. We propose that increasing pH played an important role in promoting cassiterite precipitation during Stage I, whereas cooling was the dominant control on Cu precipitation during Stage II. During Stage III, further cooling and increasing pH promoted Pb–Zn precipitation. The observed carbonatization and mineral assemblages are consistent with possible involvement of external fluids, including meteoric water. These changes may have been associated with fluid–rock interaction and possible mixing with meteoric water. Full article

The growing demand for flexible and wearable electronics has stimulated the development of sustainable energy-storage materials capable of maintaining electrochemical performance under mechanical deformation. Natural polymers are attractive candidates owing to their renewability, low toxicity, biodegradability, and structural versatility; however, their limited electrical conductivity and electrochemical activity often require functional reinforcement. This review critically examines natural polymer–ceramic nanocomposites developed for flexible batteries and supercapacitors, considering their use as electrodes, electrolytes, and separators. A systematic literature search identified 41 studies in which the natural polymer remained a constituent of the final functional composite, while systems employing natural polymers solely as sacrificial templates were excluded. Cellulose emerges as the most widely explored matrix, combined with a broad range of ceramic materials, including MnO₂, ZnO, SnO₂, TiO₂, Fe₃O₄, BaTiO₃, and other functional oxides and inorganic compounds. Ceramic incorporation generally improves electrochemical activity, ion transport, thermal stability, or mechanical integrity, although the reported performance strongly depends on composition, architecture, and device configuration. A major limitation across the literature is the lack of standardized mechanical and flexibility testing, which hinders meaningful comparison between systems. Future progress will require the development of multifunctional, genuinely sustainable architectures together with standardized electrochemical–mechanical testing, biodegradability and end-of-life assessments, and scalable manufacturing strategies. Full article

This work proposes the study of light-sensitive resistive sensors composed of dispersed heterojunctions (BHJs) in a poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) matrix, fabricated from cobalt and palladium porphyrins (CoOEP and PdOEP), and mixed with ethylanthraquinone (EAQ). Topographical characterization was performed using atomic force microscopy. In addition, the BHJs were characterized by their transmittance and fluorescence, and their band gap of 3.6 eV was similar for both heterojunctions and independent of the metal in the porphyrin. However, transmittance and fluorescence are more strongly correlated with the metal of the macrocycle. With PdOEP-EAQ/PEDOT:PSS and CoOEP-EAQ/PEDOT:PSS films as active layers, sensitive resistive sensors were fabricated and optimized by embedding SnO₂ and ZnO nanoparticles in PEDOT:PSS, as well as aluminum hydroxyquinoline, within the same polymer matrix. The devices fabricated on Tetra Pak and glass substrates were electrically characterized over a voltage range of −1.1 to 1.1 V under both white illumination and darkness. The results show that glass devices deposited with SnO₂-PEDOT:PSS and ZnO-PEDOT:PSS exhibit improved linearity of electrical conduction under dark conditions. Furthermore, for the SnO₂-PEDOT:PSS/CoOEP-EAQ device, the electron mobility and free carrier density were estimated, yielding values of ${\mu }_n=2.495\times {10}^{-3}{\displaystyle \frac{\mathrm{c}{\mathrm{m}}^2}{\mathrm{V}\mathrm{s}}}$ and $n_0=8.69\times {10}^{20}{\displaystyle \frac{1}{\mathrm{c}{\mathrm{m}}^3}}$, respectively. The manufactured devices exhibited a light-dependent resistive response, suggesting their suitability for light-sensing applications. Full article

Zn₂SnO₄ is a promising anode for lithium-ion batteries owing to its high theoretical capacity, yet its practical utilization is severely limited by sluggish reaction kinetics, large volume expansion, and unstable electrode/electrolyte interfaces. Here, we introduce a dimensionality-reduction strategy that simultaneously boosts capacity and cycling stability. Through surfactant-directed crystal growth, acid-etching reconstruction, and hydrothermal carbon coating, compact Zn₂SnO₄ octahedra are controllably transformed into sheet-assembled structures and finally into a core–shell composite with a continuous carbon layer (C@M-Zn₂SnO₄ (H⁺)). The continuous structural evolution shortens Li⁺ diffusion paths, buffers mechanical stress, and stabilizes the solid–electrolyte interface without altering the intrinsic lithium-storage mechanism of Zn₂SnO₄. As a result, the optimized C@M-Zn₂SnO₄ (H⁺) electrode delivers a reversible capacity of 650 mAh g⁻¹ after activation and retains 620 mAh g⁻¹ after 600 cycles at 200 mA g⁻¹, with Coulombic efficiency approaching 100% throughout. This work demonstrates that dimensionality-reduction-assisted structural engineering is an effective strategy for developing high-capacity, long-cycle-life anode materials. Full article

New approaches to the band gap engineering of ZnO:Fe/SnO₂ nanocomposites are developed in this study. The main idea is to control the band structure of the material by varying the modifier (iron) content during the preparation of the film-forming sol and the co-evolution of its components. Experimental X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDX) data demonstrate that materials with controlled crystallite size and hierarchical morphology can be obtained with Fe contents ranging from 1 to 6 at.%. For the first time, a combined analysis of XPS data and Tauc plot band gap measurements demonstrates preferential doping of zinc oxide within the composite studied. It is also found that the formation of type II heterostructures at Fe concentrations of up to 4 at.% takes place. The authors suggest that the formation of a Z-scheme heterostructure occurs at iron contents of 5 and 6 at.%, and X-ray amorphous phases act as charge transfer mediators. It is established that the photocatalytic properties of the material are determined by the interrelations between the band structure of the material and the spectral characteristics of the radiation sources, while optical power is not a dominant factor. Using the ZnO/SnO₂ nanocomposite ensures 98.12% decomposition of Brilliant Green in 120 min under short-wave UV radiation, while using the photocatalytic material containing 6 at.% iron ensures 95.84% degradation of the dye in the same time under soft UV radiation. Employing a low-power lamp simulating the solar spectrum in the 380–780 nm range enables 24.91% decomposition of the organic pollutant when using ZnO:Fe(5 at.%)/SnO₂ as a photocatalyst. Full article

Juniperus species form critical, long-lived high-mountain forest ecosystems in Central Asia, serving essential phytocoenotic and ecological functions in environmentally challenging habitats. However, the relationships between the elemental composition of these evergreen conifers and their underlying soils remain poorly understood. This study evaluated and compared the distribution of major elements (Fe, Ca, P, Mg, Al, Na, K, S), trace elements (Cu, Pb, Zn, Ni, Co, Mn, As, Cd, Cr, Mo, U, Th, Sr, Sb, Bi, V, La, Ba, Ti, B, W, Sc, Zr, Tl, Ta, Nb, Se, Te, Ga, Cs, Ge, Hf, Rb, Sn and others), and environmental pollution indices (Igeo, EF, CF, BAF) in plant tissues (leaves and cones) and canopy soils of three key juniper species (Juniperus seravschanica, J. turkestanica, and J. semiglobosa) in the Fann Mountains, Tajikistan. Soil and plant samples were collected across natural habitats and analyzed for total chemical composition using ICP-OES. The soils showed a near-neutral reaction (pH 7.02–7.42 in H₂O and 6.41–7.15 in KCl), with considerable variability in Corg. content (5.04%–21.82%) and Nt content (0.337%–1.149%) in the humus (A) horizons. Geochemical indices (Igeo up to 2.42, EF up to 35.30) indicated noticeable soil enrichment and localized contamination by arsenic (As) and cadmium (Cd), likely driven by a combination of regional industrial and mining activities alongside natural geogenic enrichment. Across all sites, elemental concentrations followed a consistent sequence: soil > leaves ≈ cones. Heavy metals in plant tissues remained well below toxic thresholds. High organ-specific partitioning was observed: K predominated in cones (K > Ca > P), whereas Ca and Fe accumulated predominantly in leaves (Ca > K). Low bioaccumulation factor values (BAF < 1) indicate limited element accumulation relative to total soil concentrations for all three species, which may be influenced by both reduced bioavailability in neutral-to-alkaline soils and potential physiological regulation. As the first data reported from this region, these findings establish an essential baseline for long-term ecological monitoring, soil–plant chemistry, conservation, and environmental risk assessment in the Fann Mountains’ juniper ecosystems. 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

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

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

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

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

Transparent conductive oxides (TCOs) are indispensable core materials for optoelectronic devices, yet the inherent conflict between electrical conductivity and optical transparency, along with the scarcity and brittleness of indium tin oxide (ITO), severely limits their sustainable development. This review systematically summarizes the research progress of next-generation TCOs, focusing on microstructural engineering, advanced doping strategies, and architectural innovation to decouple the conductivity–transparency trade-off. The fundamental mechanisms of carrier scattering (ionized impurity scattering, grain boundary scattering) and the mobility-centric design paradigm are elaborated. The research status of typical material systems (SnO₂-based, ZnO-based, In₂O₃-based) is analyzed, and the mechanisms of high-valent cation doping, interstitial doping, and critical nucleation in optimizing carrier mobility are clarified. The oxide/metal/oxide (OMO) multilayer architecture is highlighted as a breakthrough strategy for synergistic optoelectronic performance. Current challenges including thermal stability, large-area fabrication, and environmental reliability are discussed, and future directions such as resonant doping, machine learning-assisted optimization, and multifunctional integration are prospected. This work provides a systematic theoretical basis and technical reference for the development of high-performance, sustainable TCOs. Full article

Cadmium sulfide has been widely used as a conventional n-type window/buffer layer or heterojunction partner in several p-type thin-film solar cells, including CdTe/CdSeTe-, chalcopyrite-, kesterite-, antimony chalcogenide-, tin sulfide- and iron pyrite-based devices. Its success is related to its ability to form suitable heterojunctions, partially passivate absorber surfaces and provide favorable electronic selectivity. However, the parasitic absorption associated with the relatively narrow band gap of CdS, the toxicity and waste-management issues related to cadmium-containing auxiliary layers and the need for improved band alignment have motivated extensive research on CdS-free window and buffer layers. This review summarizes the main efforts devoted to replacing CdS in thin-film solar cells based on absorbers such as CdTe/CdSeTe, CIS, CIGS, CZTS, CZTSe, CZTSSe, Sb₂S₃, Sb₂Se₃, Sb₂(S,Se)₃, SnS and FeS₂. The most investigated alternative materials, including Zn(O,S), ZnS, In₂S₃, ZnMgO, ZnSnO, TiO₂, SnO₂ and SnS₂, are discussed with emphasis on their optical properties, band alignment, interface quality, deposition methods and impact on device performance. The analysis highlights that CdS replacement cannot be treated as a universal material substitution problem. Instead, each absorber and device architecture requires a specific front-interface design, where chemical compatibility, conduction band offset, defect passivation, optical transparency and process-induced interfacial modifications play a decisive role. CdS-free approaches are relatively mature for CdTe/CdSeTe- and CIGS-based solar cells, whereas kesterite absorbers, antimony chalcogenides and SnS still require further interface engineering. In FeS₂, by contrast, buffer-layer substitution remains secondary to the control of intrinsic surface and bulk electronic defects. This review provides a concise comparison of the most relevant CdS-free front/window materials and identifies key challenges for the future design of sustainable thin-film solar cells. Full article

In our day-to-day lives, we are regularly exposed to a wide spectrum of dangerous gases. Their origins vary, ranging from industrial activities to objects found within our very homes. Naturally, there is an interest in developing cost-efficient and durable devices that can successfully track these gases within our environment. One such candidate is represented by chemoresistive gas sensors based on metal oxides. This is due to their simple architecture and the possibility of scaling down their size, making them valid contenders for future advancements in portable gas sensors. This review focuses on chemoresistive gas sensors that have been obtained through different Physical Vapor Deposition (PVD) methods, which are easily scalable for potential technological transfer towards commercialization or are already exploited at the industrial level, and how varying different deposition parameters impacts the structure of the active material, thus modifying the gas sensing properties of the device. In this review, we report results obtained for different metal oxides: WO₃, ZnO, CeO₂, TiO₂, NiO, and SnO₂. The main findings of these studies revealed that the sensor’s response was highly impacted by oxygen deficiencies within the deposited material, the specific surface area, and the thickness of the film. Moreover, this study also delves into different strategies of functionalization that result in improved gas sensing properties. Thus, we herein report how tailoring functional properties modifies the gas sensing performance of different metal oxides. Full article