Three-dimensional Silver Research Articles

Silver Decoration of Vertically Aligned MoS2-MoOx Nanosheets: A Comprehensive XPS Investigation.

This study investigates the simultaneous decoration of vertically aligned molybdenum disulfide nanostructure (VA-MoS2) with Ag nanoparticles (NPs) and nitrogen functionalization. Nitrogen functionalization was achieved through physical vapor deposition (PVD) DC-magnetron sputtering using nitrogen as a reactive gas, aiming to induce p-type behavior in MoS2. The utilization of reactive sputtering resulted in the growth of three-dimensional silver structures on the surface of MoS2, promoting the formation of silver nanoparticles. A comprehensive characterization was conducted to assess surface modifications and analyze chemical and structural changes. X-ray photoelectron spectroscopy (XPS) showed the presence of silver on the MoS2 surface. Scanning electron microscopy (SEM) confirmed successful decoration with silver nanoparticles, showing that deposition time affects the size and distribution of the silver on the MoS2 surface.

Silver nanopopcorns decorated on flexible membrane for SERS detection of nitrofurazone.

Thesynthesis of three-dimensional silver nanopopcorns (Ag NPCs) onto a flexible polycarbonate membrane (PCM) for the detection of nitrofurazone (NFZ) on the fish surface by surface-enhanced Raman spectroscopy (SERS)is presented. The proposed flexible Ag-NPCs/PCM SERS substrate exhibits significant Raman signal intensity enhancement with the measured enhancement factor of 2.36 × 106. This is primarily attributed to the hotspots created on Ag NPCs, including numerous nanoscale protrusions and internal crevices distributed across the surface of Ag NPCs. The detection of NFZ by this flexible SERS substrate demonstrates a low limit of detection (LOD) of 3.7 × 10-9M and uniform and reproducible Raman signal intensities with a relative standard deviation below 8.34%. It also exhibits excellent stability, retaining 70% of its efficacy even after 10days of storage. Notably, the practical detection of NFZ in tap water, honey water, and fish surfaces achieves LOD values of 1.35 × 10-8M, 5.76 × 10-7M, and 3.61 × 10-8M,respectively, which highlights its effectiveness across different sample types. The developed Ag-NPCs/PCM SERS substrate presents promising potential for sensitive SERS detection of toxic substances in real-world samples.

Cotton swabs wrapped with three-dimensional silver nanoflowers as SERS substrates for the determination of food colorant carmine on irregular surfaces.

A lightweight, portable, low-cost, and accessible cotton swab was employed as surface enhanced Raman spectroscopy (SERS) matrix template. The silver nanoflowers were in situ grown on the surface of cotton swabs to form three-dimensional Ag nanoflower@cotton swabs (AgNF@CS) SERS substrate with high-density and multi-level hot spots. The SERS performance of AgNFs@CS substrates with various reaction time was systematically studied. The optimal AgNF-120@CS SERS substrate exhibits superior detection sensitivity of 10-10M for methylene blue, good signal reproducibility, high enhancement factor of 1.4 × 107, and excellent storage stability (over 30days). Moreover, the AgNF-120@CS SERS substrate also exhibits prominent detection sensitivity of 10-8M for food colorant of carmine. Besides, the portable AgNF-120@CS SERS substrate is also capable of detecting food colorant residues on irregular food surfaces.

Nano-silver@polydopamine carbonized melamine foam supported polyethylene glycol phase change materials: With simultaneous improved photo-thermal conversion ability

Ag nanoparticles are commonly used for phase change material (PCM) modification to improve the photo-thermal convertibility in composite phase change materials (CPCM) owing to enhance carrier's ability to absorb photons by virtue of its unique localized Surface Plasmon Resonance effect (LSPR). Currently, redox method is considered to be the most effective method for the preparation of Ag nano-coating. However, it is still challenging to obtain a dense and uniform Ag nano-coating on the carrier surface due to the difference in the binding force between Ag nanoparticles and different carriers. Herein, a new preparation strategy is demonstrated, in which the carrier is pre-modified by adding a polydopamine (PDA) coating to enhance the bonding between the carrier and the silver nanoparticles, and then a stable three-dimensional silver nano-conducting network is obtained by redox. Consequential stable architecture contributes to polyethylene glycol (PEG) loadings reach 98%, simultaneously with an ultra-high photo-thermal conversion efficiency of 97.9%. Furthermore, this paper demonstrates the effect of carbonization temperature on the flexibility of melamine carbon foam (CMF), and different nano-Ag concentrations on the thermal conductivity of CPCM. This finding provides valuable guidance for the engineering of high photo-thermal conversion performance CPCM and strengthens their practical implementation in solar energy storage and thermal management.

Highly Sensitive Microarray Immunoassay for Multiple Mycotoxins on Engineered 3D Porous Silicon SERS Substrate with Silver Nanoparticle Magnetron Sputtering.

A high-throughput, rapid, and highly sensitive surface-enhanced Raman spectroscopy (SERS) microarray for screening multiple mycotoxins has been developed on a three-dimensional silver nanoparticle porous silicon (3D AgNP-Psi) SERS substrate, which was easy to be engineered by electrochemical etching and magnetron sputtering technology. The etching current density, etching waveform, and target material for magnetron sputtering have been investigated to obtain an optimal 3D SERS substrate. The optimized 3D AgNP-Psi SERS substrate showed an enhancement factor of 2.3 × 107 at 400 mA/cm2 constant current density etching for 20 s and Ag target magnetron sputtering for 200 nm thickness on the surface of Psi. The simulation electric field distribution showed the near-field enhancement can reach 3× higher than that of AuNPs. A protein microarray has been designed to screen multiple mycotoxins by AuNP Raman tags and a competitive immunoassay protocol on the surface of the 3D SERS substrate. The SERS protein microarray displayed wide linear detection ranges of 0.001-100 ng/mL for ochratoxin A, 0.01-100 ng/mL for aflatoxin B1, 0.001-10 ng/mL for deoxynivalenol, along with pg/mL low limit of detection, good recovery rates, repeatability, and reproducibility. The 3D SERS protein microarray is easily engineered and has a great potential application in medicine, environment, and food industry fields.

Plastron effect enhanced electrochemical CO2 reduction activity over hydrophobic three-dimensional nanoporous silver.

The electrochemical reduction of CO2 on catalyst surfaces is hindered by the inefficient mass transfer of CO2 in aqueous solutions. In this study, we employed an electrochemical reduction approach to fabricate a hydrophobic three-dimensional nanoporous silver catalyst with a plastron effect, aiming to enhance the CO2 diffusion. The resulting catalyst exhibited an exceptional performance with the FECO peaking at 95% at -0.65 V (vs. RHE) and demonstrated remarkable stability during continuous electrolysis for 48 hours. Control experiments, together with Tafel analysis, EIS measurements, and contact angle results, confirmed that the notable enhancement of performance was attributed to the hydrophobic porous structure that facilitated efficient storage and rapid mass transfer of low-solubility CO2 gas reactants.

Fabrication of 3D popcorn-like Ag microstructures film array substrate: SERS and catalytic property

Surface-enhanced Raman scattering (SERS) has tremendous significance in the fields of ultrasensitive detection and real-time in situ monitoring in catalysis. However, it remains a challenge to simultaneously achieve higher-quality SERS and excellent plasmonic catalytic properties in a nano/microstructure substrate under random excitation light. Here, we propose the design of a three-dimensional (3D) popcorn-like silver (Ag) microstructure (MS) with diameter of 1.2 ± 0.1 µm and a unique rough surface topography, realize a wide surface plasmon resonance (SPR) band ranging from 300 nm to 1100 nm, approximating a full spectrum. The popcorn-like Ag MSs with full-spectrum property effectively broaden the spectral overlap between the SPR band and wavelength of excitation light or absorption of probe molecules. Moreover, the 3D popcorn-like Ag MSs were used to construct a monolayer film array substrate on silicon wafer with a good homogeneity over large areas by an interfacial self-assembly method. The monolayer Ag MSs film array substrate can provide abundant “hot spots” and present excellent SERS performance for sensitive detection of Rhodamine 6G (Rh6G) with a low detection limit of 10−9 M. The single-layer Ag MSs film array with superior SERS activity is utilized for in situ monitoring the plasmonic catalytic kinetics of 4-nitrothiophenol (4-NTP) dimerized into 4, 4′-dimercaptoazobenzene (DMAB) under 532 nm and 785 nm excitation, respectively. The mechanism on plasmonic catalytic reaction of the popcorn-like Ag MSs substrate is systemically investigated by experimental and theoretical simulations aspects. The Ag MSs film array substrate will offer a new strategy to further explore applications of SERS in sensors, photocatalysis, and bio/chemical analysis.

Preparation of amorphous silver-ear-shaped CoNi2S4 cathode materials by sacrificial template method and its performance in asymmetric supercapacitors

Three-dimensional amorphous silver lug-like CoNi2S4 electrode materials have been designed and synthesised by the sacrificial template method. Through a clever combination of Ni2+ induced template deficiency and sulphidation reactions, the rearrangement of the electronic structure can be promoted, generating more defects. The Ni element-doped electrode significantly improves the capacitance due to the bimetallic synergy and has a high mass specific capacitance of 1351 F g −1 at a current density of 4 A g −1. The specific capacitance was 1111 F g −1 at a current density of 20 A g −1, showing an excellent multiplicative performance (82.2%).

Thermally Conductive, Electrically Insulating Epoxy Pads with Three-Dimensional Polydopamine-Modified and Silver Nanoparticle-Functionalized Hexagonal Boron Nitride Networks

Thermally Conductive, Electrically Insulating Epoxy Pads with Three-Dimensional Polydopamine-Modified and Silver Nanoparticle-Functionalized Hexagonal Boron Nitride Networks

One-Step, On-Site Chemical Printing of a 3D Plasmon-Coupled Silver Nanocoral Substrate toward SERS-Based POCT

Surface-enhanced Raman scattering (SERS) with the advantages of high sensitivity, nondestructive analysis, and a unique fingerprint effect shows great potential in point-of-care testing (POCT). However, SERS faces challenges in rapidly constructing a substrate with high repeatability, homogeneity, and sensitivity, which are the key factors that restrict its practical applications. In this study, we propose a one-step chemical printing strategy for synthesizing a three-dimensional (3D) plasmon-coupled silver nanocoral (AgNC) substrate (only need about 5 min) without any pretreatments and complex instruments. The galvanic replacement between AgNO3 and Cu sheets will provide both Ag0 for the formation of silver nanostructures and Cu2+ for the polymerization of fish sperm DNA (FSDNA). The protection of AgNCs is facilitated by the crosslinked FSDNA, which can improve the stability of the substrate and promote the control of its coral-like morphology. The obtained substrate displays excellent capacity of signal enhancement due to the 3D plasmon coupling both between nanocoral tentacles and between nanocorals and Cu sheets as well. Therefore, the AgNC substrates display high activity (enhancement factor = 1.96 × 108) and uniformity (RSD < 6%). Food colorants have been widely used in various foods to improve their color, but the inevitable toxicity of colorants seriously threatens food safety. Therefore, the proposed AgNC substrates were used to directly quantify three kinds of weak-affinity food colorant molecules including Brilliant Blue, Allura Red, and Sunset Yellow assisted by the capture by cysteamine hydrochloride (CA), showing the detection limits (S/N = 3) of 0.053, 0.087, and 0.089 ppm, respectively. The SERS method has been further applied in the detection of the three kinds of food colorants in both complex food samples and urine with recoveries of 91-119%. The satisfactory detection results suggest that the facile preparation strategy of AgNC substrates will be widely used in SERS-based POCT to promote the development of food safety and on-site healthcare.

Ratiometric response to formaldehyde by 3D silver SERS substrate with polyoxometalate as internal label

For surface-enhanced Raman scattering (SERS) analytical technology, the rational design of efficient substrate and effective internal standard is the key issue to implement the reliable detection. In this paper, a novel three-dimensional (3D) silver(I)-polyoxometalate complex of Ag2[Ag(trz)2][H6CrMo6O24]·2H2O (Ag3CrMo6, trz = 1, 2, 4-triazole) has been designed and synthesized, which can be used for the quantitative detection of formaldehyde (FA). Structural analysis reveals that the [H6CrMo6O24]3- polyoxoanions link Ag+ by diverse Ag−O(Mo−O) bonds to form a stable 3D framework. When Ag3CrMo6 is exposed to FA, the Ag+ can be partially reduced to Ag0 species to become the label-free SERS active substrate and and present the enhanced signals ascribed to the Mo−O vibrations. Due to that the reduced Ag0 species is only close to Mo−O groups, the Raman signals for Cr−O bonds are almost constant and can be used as internal standards. Therefore, the IMo−O/ICr−O values can be used as ratiometric SERS signals to fulfill the elusive SERS quantitative analysis for FA with the detection limit of 0.05 ng/L. This work opens up an innovative way to the rational design of label-free SERS substrate based on polyoxoanions and silver ions, by which the quantitative detection can be realized via the ratiometric Raman signals.

A three-dimensional DNA walker and silver nanoparticles promoting lattice-strain-driven photo-induced electron transfer for high-performance semi-homogeneous biosensing

As an important tumor marker, the ultra-sensitive detection of low-abundance microRNAs provides important data support for early warning of tumors. Herein, taking microRNA-141 as the target model, a novel enzyme-free semi-homogeneous photoelectrochemical (SHO-PEC) biosensor was designed by entropy-driven three-dimensional (3D) DNA walker with exponential signal amplification, magnetic enrichment and separation of pseudo-targets, bridged CdTe@ZnS quantum dots to promote photocathodic current enhancement, and in situ generated silver nanoparticles (NPs) to accelerate charge separation. In this protocol, ZnS shell passivates the surface defects of the soft core CdTe, introducing considerable strain that causes electrons to extend towards the shell, which is responsible for the higher photocurrent response. Also, the Ag NPs enable ultrafast photogenerated electron transfer by forming Schottky junctions. These two unique sensitized mechanisms were proposed for the first time in PEC sensing. Moreover, a one-step simple electrode modification strategy avoids tedious layer-by-layer assembly and rinsing steps. These make the "signal-on" SHO-PEC biosensor with remarkable advantages of high sensitivity, good specificity, strong reliability, fast speed, easy operation, and low cost. This research provides a new initiative for the development of PEC sensing platforms with excellent comprehensive performance.

Combining thin-film microextraction and surface enhanced Raman spectroscopy to sensitively detect thiram based on 3D silver nanonetworks

By coupling thin-film microextraction (TFME) with surface enhanced Raman scattering (SERS), a facile method was developed for the determination of thiram in the complex matrix (orange juice or grape peel). The substrate of TFME was made by self-assembling silver sol on the silicon wafer to form a three-dimensional (3D) silver nanonetwork structure, without adding any template, which was used for TFME and SERS detection, respectively. The substrate exhibits high reproducibility with a relative standard deviation of about 7.32 % in spot and spot SERS intensity. The SERS signal intensity at a shift of 1384 cm−1 and the thiram concentration showed good linearity in the range of 0.01–5 µg/L and the linear correlation coefficient was 0.9912. The detection limit for thiram was found to be 0.01 µg/L. The TFME-SERS method was applied for the determination of thiram in fruit juice and the results were obtained very well. Therefore, this method is expected to play a role in the detection of trace pollutants.

Facile and scalable preparation of solution-processed succulent-like silver nanoflowers for 3D flexible nanocellulose-based SERS sensors

The synthesis of three-dimensional (3D) silver nanostructures with prominent plasmonic characteristics is of great importance in surface-enhanced Raman scattering (SERS) sensing applications. However, the preparation of 3D Ag nanostructures often suffer from high cost, complicated operation steps, time-consuming process and special instruments. In this work, 3D succulent-like silver nanoflowers (S-AgNFs) are successfully synthesized by a simple, scalable and low-cost liquid-phase reduction method at room temperature. The S-AgNFs with a diameter that ranges from 500 to 800 nm are composed of nano-petals that are about 60 nm in thickness. The growth process of S-AgNFs is systematically observed and investigated. And the solution-processed S-AgNFs are served as flexible SERS sensors via facile vacuum-assisted filtration onto bacterial nanocellulose (BNC) membranes. Attributed to unique 3D nanostructures of S-AgNFs, the as-prepared S-AgNFs@BNC SERS sensor with high-density and multi-level hotspots exhibits ultra-high detection sensitivity of 10−13 M for malachite green (MG), impressive enhancement factor of 1.2 × 1010, good signal reproducibility and remarkable stability. Moreover, the flexible S-AgNFs@BNC SERS sensor also demonstrates excellent detection sensitivity of 10−10 M for detecting pesticide residues on irregular surfaces. The flexible, stable and ultrasensitive S-AgNFs@BNC SERS sensor is promising for application in rapid identification of hazardous molecules, bacteria and viruses.

High stretchability and conductive stability of flexible hybrid electronic materials for smart clothing

In this study, a flexible hybrid electronic (FHE) material with enhanced conductivity was developed and successfully applied to electromyograms (EMG) and electrocardiograms (ECG) of smart clothing. The FHE material comprises a highly stretchable patterned circuit with dry flexible electrodes. The pre-stretched circuit was obtained by mixing three-dimensional (3D) dendritic silver nanoparticles (AgNPs) with two-dimensional (2D) reduced graphene oxide (rGO) in a thermoplastic elastomer and patterning the resultant as wires using steel plate stencil printing. Based on the nano-dispersion principle, the geometrical differences of nanomaterials could be exploited to form a 3D continuous phase conductive network with improved tensile properties. A highly stretchable and bendable conductive film with a resistance of 1.4 × 10−2 ohm/sq was obtained by mixing 80 wt% of 3D dendritic AgNPs and 1 wt% of rGO to produce pre-strained nanowires with a horseshoe pattern. Furthermore, the conductive film could be coated with a polyurethane (PU) layer to achieve good stability in the washing test. In the tensile fatigue test, the resistance variation ΔR of horseshoe patterned nanowire was only 1.9 ohm under 500 stretches. Additionally, a low-resistance film (∼103 ohm.cm) was fabricated by adding 7 wt% of carbon black and 2D graphene nanoplatelets (CB/GNPs, 4:1) and styrene maleic anhydride-amide (SMA-amide, 10:1 ratio with carbon material), yielding superior fatigue resistance. Finally, a design combining the pre-stretched circuit pattern with dry sensing flexible conductive electrodes was developed and successfully applied for EMG and ECG of smart clothes.

Super-Stretchable and Self-Healing hydrogel with a Three-Dimensional silver nanowires network structure for wearable sensor and electromagnetic interference shielding

With the rapid development of the electronics industry, smart wearable electronics and electromagnetic interference (EMI) shielding materials have attracted tremendous interest. However, it is still a great challenge to maintain stable performance after damage. Herein, we prepare a super-stretchable and self-healing hydrogel composite with exceptional EMI shielding performance by the in situ polymerization of the acrylamide (AAm) and N-acryloyl-11-aminoundecanoic acid (A-11) in the silver nanowires (AgNWs) aerogel with a cellular structure. Benefiting the continuous three-dimensional AgNWs network, the hydrogel composite has high electrical conductivity (83 S/cm), outstanding resistance-strain response of more than 800% tensile strain, and exceptional EMI effectiveness (SE) of 66 dB in X-band, capable of monitoring human motions as a wearable sensor. Moreover, the reversible hydrophobic association and hydrogen bonding interactions endow the hydrogel composite with excellent self-healing capability (EMI SE healing efficiency of 90%). The healed hydrogel composite can still serve as a sensor to respond rapidly and steadily to human motions. The super-stretchable and self-healing hydrogel composite holds great promise for smart wearable electronics and EMI shielding.

In situ detection of fluid media based on a three-dimensional dendritic silver surface-enhanced Raman scattering substrate

A simple substitution reaction was used to grow 3D dendritic silver structures in microfluidic channels, and a highly active SERS detection platform was formed. The system can realize in situ detection of 10−10 mol L−1 R6G solution.

Super-Stretchable and Self-Healing Hydrogel with Three-Dimensional Silver Nanowires Network for Wearable Sensor and Electromagnetic Interference Shielding

Super-Stretchable and Self-Healing Hydrogel with Three-Dimensional Silver Nanowires Network for Wearable Sensor and Electromagnetic Interference Shielding

Highly reversible zinc metal anodes enabled by a three-dimensional silver host for aqueous batteries

The spontaneously generated Ag–Zn alloys on the surfaces of three-dimensional Ag meshes make them promising candidates for improving the reversibility of Zn anodes in mild acidic electrolyte.

Flexible composite Ag-AgNWs-CF as low noise marine electric field sensor

Carbon fibers (CF) have triggered extensive interest with the progress of multifarious marine electric field sensor devices owing largely to their high flexibility, good conductivity and exceptional chemical/thermal stability. Herein, flexible Ag/sliver nanowires (AgNWs)/CF (Ag-AgNWs-CF) electrodes with extremely tiny potential difference drift of 67.22 μV/24 h have been successfully fabricated by a facile alcohol-thermal method with a reaction temperature of 170℃ for 120 min. The conductive AgNWs was introduced to the CF as a coating material. The AgNWs with three-dimensional (3D) network and silver particles accounts for superior areal specific capacitance and low Tafel slope for the composite electrodes (CEs). Using such flexible Ag-AgNWs-CF as a marine electric field sensor, the excellent self-noise was obtained, which signifies prospective ability to respond to weak signals.