Layer Of Silver Nanoparticles Research Articles

Highly durable yarn-based strain sensor with enhanced underwater monitoring capabilities and rapid drowning detection for safety applications

Flexible strain sensors have garnered significant attention for their outstanding performance in fields such as telemedicine, motion management, and human–machine interfaces. However, in the demanding marine environments, these advanced sensors face challenges related to mechanical weakness, stability, and durability under wet conditions, which are critical for expanding their range of practical applications. In this study, a stable and durable yarn sensor was developed specifically tailored for underwater activity monitoring. This was achieved by using polydopamine to immobilize silver nanoparticles, thereby creating a highly conductive layer, followed by applying an impregnation coating to establish a hydrophobic layer. The resulting composite structure featured a micro-convex layer of silver nanoparticles, which provided a durable hydrophobic surface resistant to mechanical wear and capable of maintaining its electrical properties even under high-velocity water impacts. More significantly, a FWAS was engineered, which is activated by pre-stretching the yarn sensor using a water-soluble vinylon yarn. The FWAS automatically alters its resistance within 1.3 s upon detecting someone falling into the water, thereby sending out an accurate distress signal to the external world by transmitting Morse code signals via gesture movements. This innovation provides a straightforward and effective approach for timely rescue operations from drowning, demonstrating the versatility of yarn-based flexible strain sensors for use not only in air but also in underwater scenarios.

Ultrasensitive electrochemical sensor based on dimethylglyoxime/carbon paste electrode modified with a bimetallic nanocomposite for nickel detection in environmental water samples

To date, research in the monitoring of heavy metal pollution focuses on developing an advanced and selective sensor. In this study, an electrochemical sensor-based bimetallic nanocomposite modified dimethylglyoxime carbon paste electrode (DMG/CPE) was created to detect Ni2+ selectively. The bimetallic nanocomposite was prepared by depositing a thin layer of silver nanoparticles (AgNPs) on the surface of the magnetite (Fe3O4)/DMG/CPE electrode. The incorporation of Fe3O4 and AgNPs results in a synergistic effect, increasing electron transfer and expanding the electroactive surface area (from 2.78 mm2 to 3.81 mm2), hence leading to an increase in the peak current response (ΔIp = 26.15 ± 0.33 µA at modified CPE). The prepared AgNPs/Fe3O4/DMG/CPE electrode demonstrated excellent properties, allowing for a broad linear dynamic range lying between 2–10 nM; 10–100 nM; and 100–1000 nM and a limit of detection value of 0.6 nM (S/N = 3). Additionally, the developed sensor showed great sensitivity, selectivity, and reliability in the detection of Ni2+ in river water samples, making it promising for a sensitive and selective detection of Ni-contaminated water.

Facile green synthesis of silver nanoparticles: Relevance in localized surface plasmon resonance and molecular imprinted polymer sensor for detection of Tetrabromobisphenol A in electronic waste

The present study demonstrates evocatively the interest in prioritizing an environmental friendly approach. Green synthesis of metallic nano-particles is carried out, which is further incorporated with a technique known as Molecular Imprinted Polymers (MIP) to develop a highly sensitive cuvette-based localized surface plasmon resonance (LSPR) probe for the selective detection of a Tetrabromobisphenol-A (TBBPA). TBBPA is a hazardous phenolic compound, mostly found in electronic waste (E-waste), that is abundant on earth. We have fabricated an LSPR probe with the help of a transparent glass substrate. A layer of Silver nanoparticles has been decorated over the glass substrate which further has an MIP overlayer on it. The glass slide dimensions are so chosen that it can fit inside the cuvette along its one side. The absorbance spectra are then recorded for a concentration range of 0–500 ng/ml of TBBPA. The sensitivity and limit of detection of the proposed sensor have been found to be 0.228 nm/ng ml−1 and 4.68 ng/ml respectively. Also, the probe showed quite promising recovery percentage greater than 85 % in real samples. Hence, with the findings and outcomes our fabricated probe can be represented as a potential candidate in selective detection of TBBPA along with the benefits of low cost of fabrication, portable, and real-time monitoring.

Enhanced antifouling and antibacterial performances on polytetrafluoroethylene microporous membranes sputtered with silver nanoparticles

A bare polytetrafluoroethylene (PTFE) membrane has poor antifouling and antibacterial performance in the application process. In this work, the silver nanoparticle layer (AgNP-layer) was deposited onto the PTFE membrane surface via the magnetron sputtering process to overcome these limitations. Several spectra and microscopic analyses were taken to characterize the synthesized PTFE/AgNP-layer composite membranes. The effects of magnetron sputtering time on the AgNP-layer distribution, microstructure, antifouling, and antibacterial properties were systematically investigated. Our results showed the successful deposition and grafting of the AgNP-layer on the PTFE membrane surface and inside the cross-sectional pores near the membrane surface. The AgNP-layer not only improved the composite membrane wettability but also reduced its protein adsorption capacity from 88 to 39 μg, thus improving the antifouling ability of the membrane. The composite membranes could also achieve 99% and 88% antibacterial rates against Escherichia coli and Staphylococcus aureus, respectively, exhibiting good antibacterial activity.

Microfluidic integrated D-shaped optical fiber SERS probe with high sensitivity and ability of multi-molecule detection.

In order to enhance the sensitivity, integration, and practical application capability of Raman detection systems, we propose a multi-channel microfluidic integrated D-shaped optical fiber SERS (Surface-enhanced Raman scattering) probe structure. Firstly, a microfluidic polydimethylsiloxane (PDMS) channel was fabricated using a self-designed multi-channel microfluidic template. Secondly, a uniform layer of silver nanoparticles was deposited on the D-shaped optical fiber using the liquid-liquid interface method. Finally, the D-shaped optical fiber was plasma-bonded to the multi-channel microfluidic channel and a cover glass, resulting in a microfluidic integrated D-shaped optical fiber SERS probe. The prepared sample exhibited excellent detection performance for R6G (rhodamine 6 G) with a detection limit as low as 10-11 mol/L and an enhancement factor of 1.14 × 109. Moreover, the multi-channel configuration enables simultaneous detection of multiple molecules, demonstrating excellent multi-channel multiplexing capability.

Electrically conductive and magnetic nanofiber composites with an asymmetric structure for efficient electromagnetic interference shielding

Electrically conductive fabric composites (CFCs) are recently developed for wearable electromagnetic interference (EMI) shielding materials. However, it remains challenging to increase the shielding effectiveness (SE) and reduce the electromagnetic wave reflection while ensure durability. Herein, we prepare flexible and magnetic CFCs with an asymmetric structure via integration of two functional layers and subsequent interfacial fusing through photothermal treatment. The obtained asymmetric nanofiber membrane (PANM) is composed of bottom conductive layer of silver nanoparticles (AgNPs) decorated polyurethane (PU) nanofibers and top magnetic layer of PU nanofibers loaded with ferric oxide nanoparticles (Fe3O4NPs). The EMI SE of the PANMs in the X-band can reach 69.6 dB with the absorption coefficient A of ∼0.21. In addition, the PANMs also show good mechanical properties, electrothermal and photothermal conversion performance, great surface stability and durability. The mechanically robust and multifunctional nanofiber composites have broad application prospects in wearable electronic devices and next-generation communication technologies.

To improve device performance of self-driven heterojunction photodetectors by inserting a thin layer of silver nanoparticles into the electron-transporting layer

Lead selenide colloidal quantum dots (CQDs) are widely used in infrared photodetectors due to their size-dependent bandgap tunability, facile solution-processing techniques and low cost. Heterojunctions (HJs) are usually used to construct device to facilitate the separation of excitons and the transportation of photogenerated carriers. Based on the solution-processed HJ photodetector ITO/ZnO/PbSe/Ag, in which PbSe CQDs layer acts as the active layer and ZnO nanoparticles (NPs) layer as the electron-transporting layer, a greatly enhanced-performance was obtained after inserting 10 nm Ag NPs layer within the ZnO NPs layer close to the HJ ZnO/PbSe interface. By optimizing the concentration of Ag NPs solutions and the location of Ag NPs thin layer in ZnO film, the maximum responsivity of the self-driven HJ photodetector ITO/ZnO(50 nm):Ag-NPs(10 nm):ZnO(50 nm)/PbSe(300 nm)/Ag reaches to 6.25 mA/W with a specific detectivity D* of 5.17 ×1011 Jones under 8.5 μW/cm² 1550 nm illumination at zero bias. Further, the underlain physical mechanisms for the enhanced-performance were discussed in details. In this way, it provides a very efficient method for enhanced-performance self-driven HJ photodetectors by inserting a thin layer of metal NPs into the electron-transporting layer close to the heterojunction interface.

MIPs–SERS Sensor Based on Ag NPs Film for Selective Detection of Enrofloxacin in Food

The quinolone antibiotics represented by enrofloxacin (ENRO) are harmful to the ecological environment and human health due to illegal excessive use, resulting in increasing food residues and ENRO levels in the environment. To this end, we developed a MIPs-SERS method using surface-enhanced Raman spectroscopy (SERS) and molecularly imprinted polymers (MIPs) to detect ENRO in food matrices. Firstly, a layer of silver nanoparticles (Ag NPs) with the best SERS effect was synthesized on the surface of copper rods as the enhancing material by in situ reductions, and then MIPs targeting ENRO were prepared by the native polymerization reaction, and the MIPs containing template molecules wrapped on the surface of silver nanoparticle films (Ag NPs-MIPs) were obtained. Our results showed that the Ag NPs-MIPs could specifically identify ENRO from the complex environment. The minimum detection limit for ENRO was 0.25 ng/mL, and the characteristic peak intensity of ENRO was linearly correlated to the concentration with a linear range of 0.001~0.1 μg/mL. The experimental results showed that in comparison to other detection methods, the rapid detection of ENRO in food matrices using Ag NPs-MIPs as the substrate is reliable and offers a cost-effective, time-saving, highly selective, and sensitive method for detecting ENRO residues in real food samples.

Production of biologically active non-woven textiles from recycled polyethylene terephthalate.

Recently, various studies have focused on the development of multifunctional non-woven polyethylene terephthalate (PT; polyester) textiles. Herein, we introduce multifunctional non-woven polyester fabrics by pad dry curing silver nitrate (AgNO3 ) and aniline monomer into plasma-pretreated non-woven PT textile. This creates a nanocomposite layer of silver nanoparticles (AgNPs) and polyaniline (PANi) on the fabric surface. In order to prepare a non-woven fibrous mat, we applied the melt-spinning technique on previously shredded recycled PT plastic waste. On the surface of the cloth, PANi was synthesized by REDOX polymerization of aniline. Due to the oxidative polymerization, the silver ions (Ag+ ) were converted to Ag0 NPs. PANi acted as a conductor while AgNPs inhibited the growth of microorganisms. Microwave-assisted curing with trimethoxyhexadecylsilane (TMHDS) gave PT textiles with superhydrophobic properties. The morphological studies were performed using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The stiffness and breathability of finished non-woven PT textile materials were analyzed to establish their comfort levels. Both of Escherichia coli and Staphylococcus aureus were used to test the efficacy of the AgNPs-treated textiles as antimicrobial materials. Moreover, the processed polyester textiles showed excellent electrical conductivity and great ultraviolet-ray blocking.

Antibacterial Coating on Filtration Membranes for Treatment of Cutting Fluid

Abstract: Cutting fluids has greater significance in manufacturing processes to ensure work-piece quality, to reduce tool wear, and to improve process productivity. The specific chemical composition of an applied coolant should be strongly dependent on the scope of application. Even small changes such as presence of microorganisms such as Staphylococcus, Streptococcus, Pseudomonas, Alcaligenes etc. can influence the performance of cutting fluid and introduce risk of various skin diseases to the operator in the manufacturing processes considerably. In this project the antibacterial coating is brought into use by coating a thin layer of silver nano particles on a polypropylene filtration membrane. A coated and non-coated membrane was placed separately on the cutting fluid sump of a vertical milling machine. 10litres of cutting fluid with a Servo cut Soil content of 5% and distilled water with a concentration of 95% were used in the machine while a milling process was carried out. Then a sample of cutting fluid (about 250mL) was taken from the tank and preserved for testing purposes after passing through the filter membranes. On the same cutting fluid, the machine was run for another two days, and a third sample was taken at the end of the fourth day. The samples collected were tested at Azyme Biosciences Pvt Ltd for bacterial count (CFU/ml) and the results showed that the CFU/ ml in the sample filtered through the non-coated polypropylene filtration membrane was higher than in the sample filtered via coated polypropylene filtration membrane.

Optical Properties of ITO/Glass Substrates Modified by Silver Nanoparticles for PV Applications

The paper describes the research on optical properties of glass/ITO/Ag thin layers obtained on glass/ITO substrates with different properties. The authors will discuss the influence of silver particles and silver layer thickness on the transmission and reflection spectra of the layers and parameters, such as the width of the optical band gap, refractive index, and dieelectric function. For example, the presence of silver leads to a decrease in the transmission of the layers (compared to ITO/glass) regardless of the thickness of the silver layer, and in the case of reflection, both its increase and decrease were observed, depending on the thickness of the silver layer and the type of glass/ITO substrate used. The average transmission value in the visible region depends on the thickness of the silver nanoparticle layer and varies from ~50% to ~90%. The average refractive index takes values from the range ~1.4 to ~1.65 and does not depend on the presence and thickness of the silver layer.

Near field and far field plasmonic enhancements with bilayers of different dimensions AgNPs@DLC for improved current density in silicon solar

The effect of a bilayer of different dimension silver nanoparticles (Ag NPs) on light trapping in silicon solar cells is investigated. Here, we report on the improved performance of silicon solar cells by integrating two layers of silver nanoparticles of different sizes. We experimentally examine the plasmonic near-field and far-field effects of bilayer Ag NPs embedded within an anti-reflective DLC layer on silicon solar cells' optical and electrical characteristics. Field-Emission Scanning Electron Microscopy drove the two-dimensional differences in the size of Ag NPs. The surface plasmon resonance of the two-dimensional nanoparticles was estimated from the absorption optical spectra. External quantum efficiency measurements showed that near-field or far-field plasmonic effects altered with the Ag NPs size. The development of far fields was confirmed by measuring the solar cell performance under AM 1.5 G illumination. The impact of the far-field in the cell containing two layers of Ag NPs, which outer layer is larger dimensions NPs, improves the current density up to 38.4 mA/cm2 (by 70% compared to the bare reference cell).

Surface plasmon resonance enhanced self-powered graphene/Al2O3/InGaAs near-infrared photodetector

In recent years, there has been extensive research on improving the performance of photodetectors. In this paper, the performance of a graphene/Al2O3/InGaAs photodetector is studied. In order to reduce the dark current of this device and improve the photocurrent, the structure of the device is optimized to improve the responsivity of the device. A 2 nm thick Al2O3 layer is inserted as the passivation layer. The InP layer between the SiNx layer and the InGaAs layer is retained. It is speculated that the InP layer could reduce the defects and interface states between layers. A layer of silver nanoparticles (Ag NPs) was spin coated on the surface of the single-layer graphene, and the surface plasmon resonance of Ag NPs could enhance the local electric field of InGaAs interface and increase the light absorption of graphene, which can promote carrier generation and transmission in graphene and, thus, effectively enhance the photocurrent of device. The improved device achieves a high responsivity of 265.41 mA/W at 1064 nm and a detection rate of 4.06 × 1011 cm Hz1/2 W−1. At −1.25 V, the responsivity of the device is improved to 1618.8 mA/W.

Effect of the Filtering Layer of Silver Nanoparticles and Magnesium Oxide on the Physicochemical Properties of Water

Effect of the Filtering Layer of Silver Nanoparticles and Magnesium Oxide on the Physicochemical Properties of Water

Interface engineered silver nanoparticles decorated g-C3N4 nanosheets for textile based triboelectric nanogenerators as wearable power sources

Textile based mechanical energy harvesting devices have emerged out as potential power sources for wearable electronics. For the first time, we report the fabrication of a textile based triboelectric nanogenerator (T-TENG) composed of an active layer of silver (Ag) nanoparticles loaded graphitic carbon nitride (g-C3N4) nanosheets on carbon fibres. The triboelectric characteristics has been found to be dramatically enhanced upon combinatorial effect of Ag nanoparticles loading and interfacial engineering with the introduction of a nylon layer between nanosheets and carbon cloth fibres. With teflon as a counter triboelectric material, under mechanical agitation, the AgCN/nylon bi-layer T-TENG can generate an open circuit voltage of as high as ~ 200 V and charges a commercial capacitor up to ~85 V in only 30 s. The improvement in triboelectric characteristics of the AgCN based bi-layer T-TENG is attributed to Ag nanoparticles induced modifications of surface area, dielectric properties and intrinsic resistivity of the host material. Apart from mechanical impact, the T-TENG can generate electrical output under minute mechanical forces originating from sources like air flow and biomechanical actions when integrated to wearable clothing and the output data can be accessed remotely. The AgCN/nylon-teflon based bi-layer T-TENG is not only stable at higher operating temperatures but also exhibits a higher power conversion efficiency at an elevated temperature (up to ~65 °C), which could be explained by the energetics of the composite system. The superior output characteristics as well as thermal stability of AgCN/nylon based triboelectric nanogenerator makes it a potential candidate for integration into textile based wearable electronic devices.

<i>Malus domestica</i> and <i>Solanum lycopersicum</i> Mixtures for the Synthesis of Graphene Silver and Zinc Oxide Nanocomposites

This study reports on the novel and simple green method involving the use of apple (Malus domestica) and tomato (Solanum lycopersicum) extracts in the synthesis of electroactive layers of silver nanoparticles|graphene oxide (AgNPs|GO) and zinc oxide nanoparticles|graphene oxide (ZnONPs|GO). The surface morphology of the green synthesized nanocomposites was studied using High-Resolution Transmission Electron Microscopy (HRTEM), High-Resolution Scanning Electron Microscopy (HRSEM) while the elemental analysis was studied using Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy and X-Ray diffraction (XRD) and their optical properties were further characterised using Ultraviolet Spectroscopy (UV-vis). The electrochemical studies of these nanocomposites were achieved using cyclic voltammetry (CV) where an increase in electron conductivity of the AgNPs|GO and ZnONPs|GO nanocomposite was observed. Comparatively, the silver nanoparticulate-based platforms were observed to have superior electrochemical properties as opposed to the zinc oxide-based platform. The observed electrochemical activities of the synthesized nanocomposites are a good indication of their suitability as electroactive platforms towards the development of electrochemical sensors. Electrochemical sensors are popular in the Electrochemistry field because they may be developed using different methods in order to suit their intended analytes. As such, the synthesis of a variety of electrochemical platforms provides researchers with a vast range of options to select from for the detection of analytes.

UV‐Sinterable Silver Oxalate‐Based Molecular Inks and Their Application for In‐Mold Electronics

AbstractA new broadband UV light‐based processing method for a screen printable silver oxalate molecular ink is developed that enables structural electronics to be produced on complex thermoformed 3D objects. The production of these 3D devices is driven by the light‐induced reduction of silver oxalate to form an interfacial silver nanoparticle layer that allows the ink to transition to a viscous liquid intermediate and elongate up to 50% without cracking during thermoforming. Ultimately, this enables the development of 3D electronics devices with significantly less limitations on geometry, shape, size, and depth in comparison to commercially available inks. UV processing is also effective for 2D traces on low temperature PET substrate, where in situ produced silver nanoparticles can subsequently absorb light and further facilitate the rapid conversion of the silver oxalate to metallic silver through a self‐limiting thermal decomposition. The resulting traces have superior electrical properties and are produced in significantly less time in comparison to thermal sintering. Together, UV processing and the silver oxalate molecular ink serve as a platform for both the rapid production of conductive silver traces on low temperature substrates and the development of novel thermoformed 3D human‐machine interface devices, areas of interest for both academia and industry.

High-performance surface-enhanced Raman spectroscopy chip integrated with a micro-optical system for the rapid detection of creatinine in serum.

To improve the sensitivity of disease biomarker detection, we proposed a high-performance surface-enhanced Raman spectroscopy (SERS) chip integrated with a micro-optical system (MOS). The MOS, which is based on the micro-reflecting cavity and the micro-lens, optimizes the optical matching characteristics of the SERS substrate and the Raman detection system, and greatly improves the SERS detection sensitivity by improving the collection efficiency of the Raman scattering signal. A uniform single layer of silver nanoparticles on a gold film was prepared as the SERS substrate using a liquid-liquid interface self-assembly method. The micro-reflecting cavity and micro-lens were prepared using micro-processing technology. The SERS chip was constructed based on the MOS and the Au film-based SERS substrate, and experimental results showed an EF of 1.46×108, which is about 22.4 times higher than that of the Si-based SERS substrate. The chip was used for the detection of creatinine and the detection limit of creatinine in aqueous solution was 1 µM while the detection limit in serum was 5 µM. In addition, SERS testing was conducted on serum samples from normal people and patients with chronic renal impairment. Principal component analysis and linear discriminant analysis were used for modeling and identification, and the results showed a 90% accuracy of blind sample detection. These results demonstrate the value of this SERS chip for both research and practical applications in the fields of disease diagnosis and screening.

Synthesis of flame-retardant, bactericidal, and color-adjusting wood fibers with metal phenolic networks

Wood fibers are used as raw materials for construction and furniture owing to their specific mechanical performance, cost, and availability. However, the unsatisfactory flame retardancy and antibacterial properties of wood fibers have limited their application. In this study, the flame-retardant and antibacterial wood fibers were synthesized via metal phenolic networks (MPNs). Successive immersion of tannic acid (TA) and ferrous salt was conducted to modify wood fiber with the fabrication of a TA-Fe-wood complex, which was then superficially coated with a layer of silver nanoparticles (AgNPs) to fabricate TA/Fe/AgNPs@wood fibers via a redox reaction. Compared with untreated wood fibers, the TA/Fe/AgNPs@wood fibers demonstrate a 71.5 % reduction in peak heat release rate and a 56.5 % reduction in peak smoke production rate as well as increased char formation, indicating a significant improvement in fire resistance. The modified fibers also exhibit excellent antibacterial activity against two common pathogenic bacteria, E. coli and S. aureus. The exterior color of the modified wood fibers was modified by double pulse TA impregnation, solving the problem that MPNs darken the substrate. These fibers can be widely used in the fields of adsorption, construction, paving and greening.

A highly sensitive strain sensor with a sandwich structure composed of two silver nanoparticles layers and one silver nanowires layer for human motion detection

The fabrication of strain sensors with high sensitivity, large sensing range and excellent stability is highly desirable because of their promising applications in human motion detection, human-machine interface and electric skin, etc. Herein, by introducing a highly conductive silver nanowire (AgNW) layer between two serried silver nanoparticle (AgNP) layers, forming a sandwich structure, a strain sensor with high sensitivity (a large gauge factor of 2.8 × 105), large sensing range (up to 80% strain) and excellent stability (over 1000 cycles) can be achieved. A combination of experimental and mechanism studies shows that the high performance of the obtained strain sensor is ascribed to the synergy of the highly conductive AgNW layer, astatic AgNP layers and the presence of large cracks in stretching. As a proof-of-concept application, the obtained strain sensor can be used for highly effective human motion detection ranging from large scale motions, i.e. kneel bending and wrist flexion, to subtle scale motions, i.e. pulse and swallowing.