Search Results (360)

The widespread adoption of sodium-ion batteries (SIBs) remains constrained by the inherent limitations of conventional anode materials, particularly their inadequate electronic conductivity, limited active sites, and pronounced structural degradation during cycling. To overcome these limitations, we propose a novel redox engineering approach to fabricate oxygen-vacancy-rich SnO₂ dots anchored on reduced graphene oxide (rGO), which are encapsulated within N-doped carbon nanofibers (denoted as ov-SnO₂/rGO@N-CNFs) through electrospinning and subsequent carbonization. The introduction of rich oxygen vacancies establishes additional sodium intercalation sites and enhances Na⁺ diffusion kinetics, while the conductive N-doped carbon network effectively facilitates charge transport and mitigates SnO₂ aggregation. Benefiting from the well-designed architecture, the hierarchical ov-SnO₂/rGO@N-CNFs electrode achieves remarkable reversible specific capacities of 351 mAh g⁻¹ after 100 cycles at 0.1 A g⁻¹ and 257.3 mAh g⁻¹ after 2000 cycles at 1.0 A g⁻¹ and maintains 177 mAh g⁻¹ even after 8000 cycles at 5.0 A g⁻¹, demonstrating exceptional long-term cycling stability and rate capability. This work offers a versatile design strategy for developing high-performance anode materials through synergistic interface engineering for SIBs. Full article

The inferior electrical conductivity and elevated hardness of AgSnO₂ electrical contact materials have impeded their development. To investigate the effects of Co, Bi, and La doping on the stability and electrical properties of AgSnO₂, this study established interfacial models of doped AgSnO₂ based on first-principles calculations initiated from the atomic structures of constituent materials, subsequently computing electronic structure parameters. The results indicate that doping effectively enhances the interfacial stability and bonding strength of AgSnO₂ and thereby predicted improved electrical contact performance. Doped SnO₂ powders were prepared experimentally using the sol–gel method, and AgSnO₂ contacts were fabricated using high-energy ball milling and powder metallurgy. Testing of wettability and electrical contact properties revealed reductions in arc energy, arcing time, contact resistance, and welding force post-doping. Three-dimensional profilometry and scanning electron microscopy (SEM) were employed to characterize electrical contact surfaces, elucidating the arc erosion mechanism of AgSnO₂ contact materials. Among the doped variants, La-doped electrical contact materials exhibited optimal performance (the lowest interfacial energy was 1.383 eV/Ų and wetting angle was 75.6°). The mutual validation of experiments and simulations confirms the feasibility of the theoretical calculation method. This study provides a novel theoretical method for enhancing the performance of AgSnO₂ electrical contact materials. Full article

In this study, a UVC photodetector (PD) was fabricated by incorporating CsI into a conventional double-cation perovskite (FAMAPbI₃) to enhance its stability. The device utilized a methylammonium iodide post-treatment solution to fabricate CsFAMAPbI₃ perovskite thin films, which functioned as the primary light-absorbing layer in an NIP structure composed of n-type SnO₂ and p-type spiro-OMeTAD. Perovskite films were fabricated and analyzed as a function of the Cs concentration to optimize the Cs content. The results demonstrated that Cs doping improved the crystallinity and phase stability of the films, leading to their enhanced electron mobility and photodetection performance. The UVC PD with an optimum Cs concentration exhibited a responsivity of 58.2 mA/W and a detectivity of 3.52 × 10¹⁴ Jones, representing an approximately 7% improvement over conventional structures. Full article

There is considerable interest in broadband nanomaterials, particularly transparent semiconductor oxides, within both fundamental research and technological applications. Historically, it has been considered that the variation in dopant concentration during the synthesis of semiconductor materials is a crucial factor in activating and/or modulating the optical and structural properties, particularly the bandgap and the parameters of the unit cell, of semiconductor oxides. Recently, tin oxide has emerged as a key material due to its excellent structural properties, optical transparency, and various promising applications in optoelectronics. This study utilized the ultrasonic spray pyrolysis technique to synthesize aluminum-doped tin oxide (ATO) thin films on quartz and polished single-crystal silicon substrates. The impact of varying aluminum doping levels (0, 2, 5, and 10 at. %) on morphology and structural and optical properties was examined. The ATO thin films were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmittance spectroscopy. SEM images demonstrated a slight reduction in the size of ATO nanoparticles as the aluminum doping concentration increased. XRD analysis revealed a tetragonal crystalline structure with the space group P42/mnm, and a shift in the XRD peaks to higher angles was noted with increasing aluminum content, indicating a decrease in the crystalline lattice parameters of ATO. The transmittance of the ATO films varied between 75% and 85%. By employing the transmittance spectra and the established Tauc formula the optical bandgap values of ATO films were calculated, showing an increase in the bandgap with higher doping levels. These findings were thoroughly analyzed and discussed; additionally, an effort was made to clarify the contradictory analyses present in the literature and to identify a doping range that avoids the onset of a secondary phase. Full article

The influence of Cd doping on the performance of ZnSn(OH)₆ (ZHS) as a gas sensor was systematically investigated through experimental and theoretical approaches. ZHS and Cd-doped ZHS samples were synthesized using the hydrothermal method. The microstructures of pure and Cd-doped ZHS were characterized using various techniques. The results revealed that the pure ZHS sample exhibits good crystallinity and an octahedral morphology with particle sizes ranging from 800 to 1900 nm. After Cd doping, the particle size range was decreased to 700–1500 nm. A systematic investigation of the gas-sensing properties revealed that Cd-doped ZHS exhibits superior sensing performance toward ethanol gas compared to pure ZHS. Under operating conditions of 240 °C, 100 ppm concentration, and 30% relative humidity, the response of ZHS to ethanol gas exhibited a significantly higher value compared to other tested gases. After Cd doping, the response approximately doubled. Density functional theory calculations of electronic structures revealed that the enhanced ethanol sensing mechanism of Cd-doped ZHS is attributed to the narrowed band gap caused by Cd doping, which increases electron concentration and enhances ${\mathsf{O}}^{-}$ ion adsorption on the surface. Full article

Dielectric capacitors have become a key component for energy storage systems, owing to their exceptional power density and swift charge–discharge performance. In a series of lead-free ferroelectric ceramic materials, BaSn_xTi_1-xO₃ (BTS) received widespread attention due to its unique properties. However, BTS ceramics with high Sn content have high efficiency (η) but low recovery energy storage density (W_rec). We incorporated the Sm element into BTS ceramics and aimed to optimize both efficiency and recoverable energy density at moderate Sn content. With the synergistic effect between Sm and Sn, the optimal composition was found at 5% Sn content with 1% low-level Sm dopants, where the energy storage density reached 0.2310 J/cm³ at 40 kV/cm. Furthermore, the thermal stability of the ceramic was investigated using temperature-dependent dielectric spectroscopy, in situ XRD, and temperature-dependent hysteresis loops. With Sm doping, the fluctuation of W_rec decreased from 18.48% to 12.01%. In general, this work not only enhances the understanding of samarium dopants but also proposes strategies for developing lead-free ferroelectric ceramics with superior energy storage properties. Full article

In the purpose of enhancing solar cell efficiency and sustainability, zinc selenide (ZnSe) and silicon (Si) play indispensable roles, offering a compelling combination of stability and transparency while also highlighting their abundant availability. This study utilizes the SCAPS_1D tool to explore diverse heterojunction setups, aiming to solve the nuanced correlation between key parameters and photovoltaic performance, therefore contributing significantly to the advancement of sustainable energy solutions. Exploring the performance analysis of heterojunction solar cell configurations employing ZnSe and Si elements, various configurations including SnO₂/ZnSe/p_Si/p⁺_Si, SnO₂/CdS/p_Si/p⁺_Si, TiO₂/ZnSe/p_Si/p⁺_Si, and TiO₂/CdS/p_Si/p⁺_Si are investigated, delving into parameters such as back surface field thickness (BSF), doping concentration, operating temperature, absorber layer properties, electron transport layer properties, interface defects, series and shunt resistance. Among these configurations, the SnO₂/ZnSe/p_Si/p⁺_Si configuration with a doping concentration of 10¹⁹ cm⁻³ and a BSF thickness of 2 μm, illustrates a remarkable conversion efficiency of 22.82%, a short circuit current density (J_sc) of 40.33 mA/cm², an open circuit voltage (V_oc) of 0.73 V, and a fill factor (FF) of 77.05%. Its environmentally friendly attributes position it as a promising contender for advanced photovoltaic applications. This work emphasizes the critical role of parameter optimization in propelling solar cell technologies toward heightened efficiency and sustainability. Full article

Highly dispersion antimony-doped tin oxide (ATO) nanoparticles were synthesized using a (220 °C, 2 L autoclave, medium scale) one-step hydrothermal method with Na₂SnO₃ and KSb(OH)₆ as precursors without a post-sintering process. The particle size reduces to a few nanometers with the increase in Sb content. The resulting various Sb-doping content ATO nanoparticles were coated onto a Ti foil substrate as an electrode for further electrochemical evaluation. The findings demonstrate that the prepared 30% Sb-doped ATO nanoparticles serve as a high-conductivity electrode material with excellent reversibility, substantial specific capacitance, and superior capacitance retention. The 30% ATO electrode exhibits the highest specific capacitance of 343.2 F g⁻¹ at a current density of 1 A g⁻¹ and maintains 93% of its capacitance after the first 10 charge/discharge cycles. The results indicate that ATO materials prepared by the hydrothermal method are promising candidates for supercapacitor electrodes. Full article

The Al-Sb co-doped SnO₂ composite thin films were prepared by the sol–gel spin-coating method. The structure, morphology, optical and electrical properties of the samples were investigated using XRD, XPS, SEM, UV-Vis spectroscopy, and Hall effect tester, respectively. It was found that when the aluminum doping amount was 15 at%, the resistivity of the sample was the lowest, and the overall optoelectronic performance was the best. Moreover, the Al-SnO₂ composite thin film transformed from an n-type semiconductor to a p-type semiconductor. When Al and Sb were co-doped, the carrier concentration increased significantly from 4.234 × 10¹⁹ to 6.455 × 10²⁰. Finally, the conduction type of the Al-Sb-SnO₂ composite thin film changed from p-type to n-type. In terms of optical performance, the transmittance of the Al-Sb co-doped SnO₂ composite thin films in the visible light region was significantly improved, reaching up to 80% on average, which is favorable for applications in transparent optoelectronic devices. Additionally, the absorption edge of the thin films exhibited a blue-shift after co-doping, indicating an increase in the bandgap energy, which can be exploited to tune the light-absorption properties of the thin films for specific photonic applications. Full article

In this work, the transport properties of charge carriers in $\beta$-Ga${}_2$O${}_3$ were investigated, along with intrinsic physical mechanisms such as lattice vibrations, impurity scattering, and interfacial effects. The high-field behavior of carrier mobility was characterized using vacuum deposition techniques for the fabrication of electrodes with ohmic contacts, and the Hall effect measurement system was employed to test the temperature-dependent mobility of Sn-doped n-type (100) and (001) $\beta$-Ga${}_2$O${}_3$ samples at a cryogenic temperature. A predictive model for $\beta$-Ga${}_2$O${}_3$ mobility was developed by examining the effects of the temperature on the scattering mechanisms based on a theoretical transport model. The experimental results for $\beta$-Ga${}_2$O${}_3$ mobility, which varied with the temperature and doping concentration, showed good agreement with the theoretical model within the temperature range of 15–300 K. The maximum discrepancy between the predictive model and the experimental data was less than 5%. This study provides valuable theoretical insights for the design and simulation of $\beta$-Ga${}_2$O${}_3$ devices. Full article

Synthesis and characterization of undoped and samarium-doped CuO–SnO₂:F thin films using the spray pyrolysis technique are presented. The effect of the samarium doping level on the physical properties of these films was thoroughly analyzed. X-ray diffraction patterns proved the successful synthesis of pure CuO–SnO₂:F thin films, free from detectable impurities. The smallest crystallite size was observed in 6% Sm-doped CuO–SnO₂:F thin films. The 6% Sm-doped CuO–SnO₂films demonstrated an increasedsurface area of 40.6 m²/g, highlighting improved textural properties, which was further validated by XPS analysis.The bandgap energy was found to increase from 1.90 eV for undoped CuO–SnO₂:F to 2.52 eV for 4% Sm-doped CuO–SnO₂:F, before decreasing to 2.03 eV for 6% Sm-doped CuO–SnO2:F thin films. Photoluminescence spectra revealed various emission peaks, suggesting a quenching effect. A numerical simulation of a new solar cell based on FTO/ZnO/Sm–CuO–SnO₂:F/X/Mo was carried out using Silvaco Atlas software, where X represented the absorber layer CIGS, CdTe, and CZTS. The results showed that the solar cell with CIGS as the absorber layer achieved the highest efficiency of 15.98. Additionally, the thin films demonstrated strong photocatalytic performance, with 6% Sm-doped CuO–SnO₂:F showing 86% degradation of ampicillin after two hours. This comprehensive investigation provided valuable insights into the synthesis, properties, and potential applications of Sm-doped CuO–SnO₂ thin films, particularly for solar energy and pharmaceutical applications. Full article

This study investigates the photocatalytic degradation of methylene blue (MB) using strontium-doped SnO₂ nanofibers synthesized via electrospinning. The 1% Sr-doped SnO₂ nanofibers exhibited remarkable photocatalytic activity, achieving 84.74% MB degradation under visible light irradiation, substantially outperforming both undoped SnO₂ nanofibers (61%) and the same catalyst under UV light (69%) under identical experimental conditions. Comprehensive electrochemical investigations revealed that Sr doping fundamentally transformed interfacial charge transfer kinetics, with 1% Sr-doped nanofibers exhibiting a remarkable three-fold decrease in charge transfer resistance (404 Ω compared to 1350 Ω for undoped samples), a dramatic enhancement in charge carrier density (5.17 × 10²² versus 9.24 × 10¹⁹ for undoped samples), and an approximately eight-fold increase in diffusion coefficient (8.78 × 10⁻¹⁰ versus 1.13 × 10⁻¹⁰ cm²s⁻¹). These electrochemical improvements were corroborated by comprehensive structural characterization, which demonstrated that strategic Sr incorporation induced beneficial oxygen vacancies, reduced crystallite size, increased microstrain, and enhanced dislocation density, collectively contributing to superior surface reactivity and accelerated photocatalytic mechanisms. This work establishes a quantitative correlation between electrochemical characteristics and photocatalytic activity in Sr-doped SnO₂ nanofibers, revealing the fundamental mechanisms that transform the SnO₂ nanostructure from UV-dependent to efficient visible light-driven catalysts for organic pollutant degradation. Full article

Sarin is an extremely toxic and fast-acting chemical warfare nerve agent that poses a serious threat to human health, necessitating the development of appropriate sensing technologies. Dimethyl methylphosphonate (DMMP), which has a chemical structure similar to that of sarin but is non-toxic, is often used as a simulation agent in related research. Among promising gas-sensing materials, CuFe₂O₄ exhibits suitable thermal stability. It is easily produced and has low toxicity. Its performance can be enhanced using heterogeneous ion doping to increase the number of surface defects and content of adsorbed oxygen. Therefore, a solvothermal method was adopted in this study to prepare CuFe₂O₄ hollow microspheres that were subsequently doped with different ratios of Sn⁴⁺ or Sn²⁺. Detailed characterizations of the obtained materials were conducted, and the corresponding CuFe₂O₄-based gas sensors were fabricated. Their gas-sensing performance against DMMP was studied to analyze and discuss the gas-sensing and sensitization mechanisms associated with Sn⁴⁺ and Sn²⁺ doping. The CuFe₂O₄-based sensor doped with 2 mol% Sn²⁺ exhibited excellent gas-sensing performance in response to a 1 ppm concentration of DMMP, with response and recovery times of 12 and 63 s, respectively. Notably, its response to 1 ppm DMMP (16.27) was 3.3-fold higher than that to 1 ppm 2-CEES (4.98). The doped CuFe₂O₄ sensor exhibited superior response–recovery characteristics and enhanced moisture resistance compared to the undoped sensor. Full article

This study presents the fabrication of a samarium-doped Ti/Sb-SnO₂/PbO₂ electrode and investigates its applications in polluted water treatment and energy conversion. Physicochemical properties were characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray powder diffraction analysis, and Raman spectroscopy. The Ti/Sb-SnO₂/Sm-PbO₂ electrode showed 2.5 times higher oxygen evolution potential activity than the Ti/Sb-SnO₂/PbO₂ electrode. Density Functional Theory was used to conduct first-principles calculations, and the obtained results indicated that Sm doping enhances the production of reactive oxygen species. The application of the Ti/Sb-SnO₂/Sm-PbO₂ electrode in carbendazim (CBZ) removal was investigated, since CBZ is a fungicide whose presence in the environment, including food, water, and soil, poses a threat. After 60 min of the treatment under optimized working parameters, the degradation rate of CBZ reached 94.2% in the presence of 7.2 g/L Na₂SO₄ with an applied current density of 10 mA/cm² in an acidic medium (pH 4). Of the four investigated parameters, the current density had the most significant influence on the degradation process. At the same time, the initial pH value of the solution was shown to have the least impact on degradation efficiency. These results imply a potential use of the proposed treatment for CBZ removal from wastewater. Full article

Advanced photocatalytic materials for environmental cleanup need to be developed in response to growing concerns about water pollution. This paper presents a novel N-doped hollow carbon spheres (NHCSs)-supported Co₂SnO₄/WS₂ heterostructure synthesized using a hydrothermal approach and examined using various characterization techniques to evaluate the crystal structures, functional groups, surface morphology, chemical properties, and optical characteristics. The photocatalytic performance of the Co₂SnO₄/WS₂@NHCSs composite was assessed by degrading Congo red (CR) under visible light, resulting in a notable degradation rate of 87.22% in 60 min. The enhanced degradation efficiency is ascribed to the Z-scheme heterojunction charge-transfer mechanism, which augments sustained charge separation while suppressing recombination under visible-light irradiation. Furthermore, the quenching experiments revealed that specific superoxide radicals (^•O₂^-) and hydroxyl radicals (^•OH) were integral to the degradation reaction, and a potential Z-scheme charge-transfer pathway mechanism for the effective Co₂SnO₄/WS₂@NHCSs photocatalysts was also suggested. The potential degradation mechanism was suggested using LC-MS analysis. This study highlights the promise of Co₂SnO₄/WS₂@NHCSs composites for practical wastewater treatment applications, providing a sustainable and effective solution for environmental remediation. Full article