Nanoscale Research Letters最新文献

In this study, we present a detailed investigation of the structural evolution of NMC111 (LiNi_1/3Mn_1/3Co_1/3O₂) cathode material during cycling over an extended potential window, using a combination of in situ and ex situ Raman spectroscopy, ex situ X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HR-TEM). The in situ Raman spectroscopy enabled real-time monitoring of structural changes under operating conditions, while ex situ Raman provided a more detailed post-mortem analysis. We revealed an energy-dependent Raman response that offered further insights into the electronic band structure and phase transitions within the material. We also observed a significant surface layer reconstruction at high potentials, where the NMC111 layered structure transitions into a cubic phase. This surface layer transformation is reversible during the initial stages of cycling but contributes to irreversible degradation with extended cycling, especially at elevated voltages. Ex situ XRD was employed to study the bulk structural evolution of NMC111, confirming that conventional XRD effectively captures large-scale structural changes during cycling, including significant volume variations. Additionally, TEM imaging revealed stress fringes in relithiated grains, indicating cycling-induced stress accumulation from unit cell changes and revealing particle cracking mechanism due to repeated volume fluctuations. This complete analysis provided a complementary view of both surface and bulk modifications, illustrating the advantages of integrating multiple characterization techniques. It offers valuable insights into the mechanisms behind the capacity fading, cracking of the material, and performance loss observed in lithium-ion batteries with NMC cathodes. This comprehensive understanding is essential for improving the design and performance of such batteries, particularly for high-voltage operation.

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Antibiotic resistance is a growing global health crisis. This study introduces a novel nanocomposite material incorporating superparamagnetic iron oxide nanoparticles (SPION), citric acid (CA), selenium (Se), silver (Ag), and a polymer matrix (M8) consisting of polyethylene glycol, polyvinylpyrrolidone, chitosan, and polyvinyl alcohol. The novel materials were used to inhibit Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), and Salmonella enterica (SE). The optimal molar ratio of SPION:CA: CSPION:Se: CSPION/Se/Ag was 1:2:0.5, yielding nanoparticles with an average size of 15.09 ± 2.95 nm (FE-SEM) and a saturation magnetization of 21.51 emu/g (VSM). XRD confirmed the coexistence of Fe₃O₄, Se, and Ag crystalline phases, while FTIR revealed ionic and hydrogen bonding interactions between the polymers, citric acid, and metal nanoparticles. EDS analysis validated the successful incorporation of Se (7.06 wt%) and Ag (22.00 wt%). At this ratio, the inhibition percentage against PA, SA, and SE (using the minimum inhibitory concentration method) at 50% dilution is 99.99 ± 0.52%, 99.31 ± 2.74%, and 47.41 ± 3.69%, respectively. The superior performance is attributed to synergistic effects between SPION, Se, Ag, and the polymer blend, offering a promising approach for combating antibiotic-resistant bacteria.

In this study, a comprehensive process–structure–function roadmap was established for bio-inspired functional surfaces. We systematically controlled the pore diameter, interpore distance, pore depth, and pore aspect ratio of anodic aluminum oxide (AAO) master templates via multistep anodization. These templates were then replicated in durable nickel–cobalt alloy working molds through electroforming, and their nanostructures were transferred to polycarbonate films using nanoimprint lithography. Our findings highlighted the critical influence of pre-anodization, electrolyte type (oxalic acid for an ~ 100 nm interpore distance; phosphoric acid for ~ 400 nm), anodization potential, and time on the AAO structures. We also identified 100 A/m² as the optimal current density for achieving high-aspect-ratio structures under intense anodization. The polymer film replicas obtained using these precisely controlled templates showed significantly enhanced functional properties: the average surface reflectance decreased from 10.85% to a minimum of 3.5%, transmittance increased from 80.1 to 92.3%, and water contact angles improved from 91.46 to 138.69°. Thus, a higher structural aspect ratio is crucial for enhanced hydrophobic performance, consistent with the Cassie–Baxter model. In summary, this research provides an efficient, controllable method for manufacturing high-performance bio-inspired functional surfaces and, more critically, establishes direct correlations between anodization parameters and the resulting optical and wetting properties, offering key guidance for material design.

Aedes aegypti is a primary vector of arboviral diseases, including chikungunya, dengue fever, yellow fever, and Zika virus. Given the increasing global burden and the limitations of synthetic repellents, there is a growing need for safe and effective botanical alternatives, especially in endemic regions. This study formulated thymol-, carvacrol-, and cinnamaldehyde-loaded nanoemulsions via spontaneous emulsification and subsequently gelled using hydroxypropyl methylcellulose (HPMC). Viscosity and encapsulation efficiency were assessed using viscometry and Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy. The repellent efficacy of the resulting nanogels against Ae. aegypti was assessed and benchmarked against DEET (40% w/v). The nanoemulsions exhibited particle sizes of 208 ± 5 nm, 183 ± 6 nm, and 193 ± 4 nm for thymol, carvacrol, and cinnamaldehyde, respectively. Among all formulations, carvacrol-based nanogel (3% w/v) demonstrated the longest protection time (250 ± 34 min), exceeding the commercial DEET formulation (190 ± 17 min). These findings highlight the potential of HPMC-based nanogel repellents, particularly those containing carvacrol, as effective and safer botanical alternatives to conventional repellents, with promising implications for integrated vector management strategies.

This article explores the phyto-synthesis of silver nanoparticles (Ag NPs) derived from the floral extract of Punica granatum and their potential applications in antibacterial and anticancer treatments. In the synthesis process, silver nitrate (AgNO₃) has been utilized as both a reducing and stabilizing agent, leading to the successful formation of stable silver nanoparticles (PG-Ag NPs). The nanoparticles were characterized using various analytical techniques, revealing their spherical shape and uniform dispersion, with an average size of ~ 27 (± 2) nm. The antibacterial and anticancer properties of the PG-AgNPs have been investigated, demonstrating significant anticancer activity with an IC₅₀ value of ~ 13 µg/mL. Furthermore, the nanoparticles exhibited potent antimicrobial efficacy against Escherichia coli and Staphylococcus aureus. These findings indicate that PG-Ag NPs, synthesized from Punica granatum flower extract, present a promising and cost-effective solution for antibacterial and anticancer applications.

The application of anticorrosion composite coating is a successful strategy for preventing metal corrosiveness. Application of Nanoparticles as Corrosion inhibitors effectively prevents the corrosion of metals compared to existing corrosion inhibitors. Conventional corrosion inhibitors are toxic to the environment. Following exploitation, the epoxy coatings on the steel erode as well. Nanoparticles are therefore introduced to prevent it. In this paper, NiZn₂O₄ Nanoparticles are synthesized by polymeric precursor method using alginic acid. Epoxy resin is infused with the synthesised nano NiZn₂O₄ to prevent mild steel from corroding. Nano NiO and ZnO has a high corrosion resistance. Hence NiZn₂O₄ was prepared which will have a synergistic effect thereby preventing oxidation and environment friendly. To examine its efficiency different concentrations of (1%,3%,5%) of NiZn₂O₄ nanoparticles were added to epoxy coating and applied on mild steel in 1.0 M HCl solutions. Using potentiodynamic polarisation and gravimetric (weight loss) techniques, the corrosion inhibiton efficiency was examined. A gravimetric investigation was carried out within 15 days of exposure, and the findings indicated that weight loss increase with exposure duration but diminished with higher NiZn₂O₄NP concentration. Additionally, the presence of NiZn₂O₄NPs altered the process of anodic dissolution and cathodic hydrogen gas evolution, according to potentiodynamic polarisation data from electrochemical impedance spectroscopy. From the results we observed that 3% loading of NiZn₂O₄ Nanoparticle coating was efficient with high corrosion resistance (Low corrosion rate 0.0107). These findings showed that NiZn₂O₄NPs might be added to the current inhibitors to reduce the rate of corrosion.

Hybrid organic-inorganic perovskites, with power conversion efficiencies comparable to those of polycrystalline silicon-based counterparts, as well as tunable band gaps and low-temperature solution processability, represent a promising class of optoelectronic semiconductors suitable for next-generation electronics. In this work, we synthesised high-quality single-crystal and thin films of methylammonium bismuth iodide (MBI) using an antisolvent assisted method. The X-ray diffraction analysis showed a hexagonal crystal structure for the synthesised MBI crystal with space group P6₃/mmc. The bandgap of the MBI film estimated from the absorption spectra is 2.19 eV. The thermogravimetric analysis indicates that the thermal stability of MBI exceeds that of its constituents, thereby offering improved thermal stability. Furthermore, a trap state density comparable to that of vacuum processed condition is achieved by antisolvent treatment. The impedance and dielectric characteristics of MBI are recorded for a frequency range of 100 Hz to 1 MHz and the complex impedance is analysed by fitting the Nyquist plot. A mobility of 2.29 × 10^− 6 cm² V^− 1 s^− 1 is deduced by fitting the space charge limited current (SCLC) region, and a photovoltaic analysis was performed using MBI as an absorber.

This study investigated the impact of pixel size and inter-pixel gap width on the optoelectronic performance of micro-LED arrays, with a particular focus on their application in visible light communication (VLC). Boron ion implantation was employed to define pixel emission areas and achieve effective channel insulation due to boron’s small atomic radius and its ability to suppress electrical conductivity in implanted regions without significantly degrading the optical performance. The micro-LED arrays, with a total emitting area of 14,400 μm², incorporated pixel sizes of 5 μm, 8 μm, and 10 μm, alongside gap widths of 2 μm, 4 μm, 6 μm, and 8 μm. The experimental results demonstrated a consistent increase in light output power and external quantum efficiency (EQE) with decreasing gap widths, which is attributed to reduced leakage currents and minimized non-radiative recombination losses. The small size of boron ions allowed for precise electrical isolation between pixels without affecting emission properties, enabling accurate evaluation of size-dependent performance. In VLC applications, pixel size and gap width not only influenced light output power and EQE but also impacted bandwidth, full-width at half-maximum, and data transmission rates. The 12 × 12 array with a 10 μm pixel size achieved the best VLC performance, with a bandwidth of 171.88 MHz at a current density of 347.2 A/cm².