Reactive Silver Research Articles

Improving the Density and Electrical Properties of Self-Reducing Reactive Silver Inks by Suppressing Complexing Agent Evaporation

Improving the Density and Electrical Properties of Self-Reducing Reactive Silver Inks by Suppressing Complexing Agent Evaporation

One-bath dyeing and antibacterial finishing of cotton fabric using reactive dye and silver chloride: a sustainable approach

One-bath dyeing and antibacterial finishing of cotton fabric using reactive dye as colorant and silver chloride (AgCl) as an antibacterial agent was conducted to streamline the process and enhance its economic efficiency. The effectiveness of the antibacterial agent in reactive dyeing of cotton fabric, was evaluated through exhaust method with 0.5% AgCl and continuous (pad dry cure) method with 5 g/l of AgCl, utilizing various dye concentrations (1%, 3%, 5% for exhaust; 1g/l, 3g/l, 5g/l for pad dry cure) according to a standard reactive dye recipe. Characterization of the one-bath dyed, and antibacterial finished cotton fabric was performed using K/S values to determine the optimal dye shade concentration and antibacterial activity was evaluated using agar diffusion method. It was observed that the exhaust method revealed an optimum dye concentration at (AgCl 0.5% and dye 5%), while pad dry cure method showedoptimal dye concentration at (AgCl 5g/l and dye 5g/l). Antibacterial tests were conducted on the optimal specimens from both methods (AgCl 0.5%, 0.2%, dye 0.5% for exhaust; dye 5g/l, AgCl 5g/l, 2g/l for pad dry cure), showcasing resistance against bacterial growth. While inhibition zones were observed on treated specimens of the exhaust method, whereas the treated specimens of the pad dry cure method exhibited complete resistance to bacterial growth around the specimen.

Laser-based synthesis of silver nanoparticles embedded in cellulose paper for catalytic reduction of azo dyes and SERS sensing of pesticides

In this study, highly reactive bare silver nanoparticles (Ag NPs) are synthesized using the Pulsed Laser Ablation in Liquid (PLAL) technique. Ag NPs are then coated on the filter paper using the dip coating method. This process converts filter paper into a versatile substrate for catalysis and surface-enhanced Raman Spectroscopy (SERS) based sensing. The successful synthesis of spherical Ag NPs and their effective embedding into the filter paper was confirmed using UV–visible absorption spectroscopy, scanning electron microscopy (SEM), and Energy Dispersive x-ray analysis (EDX). SEM images revealed that the Ag NPs were embedded in the filter paper and attached to the cellulose fibers. The use of Ag NPs embedded filter paper as a catalyst substrate for the reduction of both cationic and anionic dyes demonstrated that higher concentrations of Ag NPs on the filter paper resulted in a faster reduction. In particular, filter paper impregnated with 52 μg of Ag NPs demonstrated a complete reduction of methylene blue and methyl orange in less than a minute and 4 min, respectively. To demonstrate the practical sensing capability of the Ag NPs embedded filter paper, it was utilized as a SERS substrate. This enabled the detection of trace levels of Rhodamine 6G (R6G) and the pesticide molecule chlorpyrifos, demonstrating its potential real-world applications.

One-Step Synthesis of Silver Nanoparticles Embedded in Biobased Polyamide 56 Nanofibers with High Antibacterial Activity.

Embedded silver nanoparticles (Ag NPs) within nanofibers represent a highly promising alternative to common antimicrobial materials, due to the combined effective biocidal properties of Ag NPs with the biocompatibility and environmental friendliness of biobased polymers. In this study, we presented a novel one-step route to fabricate biobased polyamide 56 (PA56) nanofibers embedded with uniform Ag NPs. The process involved mixing reactive silver ammonia with PA56 solutions and then using formic acid as a reducing agent. Continuous electrospinning resulted in solvent evaporation, yielding Ag NPs highly dispersed within PA56 nanonet fibrous structures (PA56/Ag). Characterization assays confirmed the successful impregnation of Ag NPs in PA56 nanofibers, with an average size of about 32.4 nm. PA56/Ag nanofibers also displayed suitable morphology, mechanical properties, and good biocompatibility in vitro. Moreover, their antimicrobial effectiveness was evaluated against Staphylococcus aureus and Escherichia coli. Collectively, the proposed PA56/Ag nanofibers possess desirable characteristics suitable for antimicrobial applications.

Flexible Embedded Metal Meshes by Sputter-Free Crack Lithography for Transparent Electrodes and Electromagnetic Interference Shielding.

A facile and novel fabrication method is demonstrated for creating flexible poly(ethylene terephthalate) (PET)-embedded silver meshes using crack lithography, reactive ion etching (RIE), and reactive silver ink. The crack width and spacing in a waterborne acrylic emulsion polymer are controlled by the thickness of the polymer and the applied stress due to heating and evaporation. Our innovative fabrication technique eliminates the need for sputtering and ensures stronger adhesion of the metal meshes to the PET substrate. Crack trench depths over 5 μm and line widths under 5 μm have been achieved. As a transparent electrode, our flexible embedded Ag meshes exhibit a visible transmission of 91.3% and sheet resistance of 0.54 Ω/sq as well as 93.7% and 1.4 Ω/sq. This performance corresponds to figures of merit (σDC/σOP) of 7500 and 4070, respectively. For transparent electromagnetic interference (EMI) shielding, the metal meshes achieve a shielding efficiency (SE) of 42 dB with 91.3% visible transmission and an EMI SE of 37.4 dB with 93.7% visible transmission. We demonstrate the highest transparent electrode performance of crack lithography approaches in the literature and the highest flexible transparent EMI shielding performance of all fabrication approaches in the literature. These metal meshes may have applications in transparent electrodes, EMI shielding, solar cells, and organic light-emitting diodes.

Reactive silver inks: a path to solar cells with 82% less silver

ITRPV silver consumption of standard low-temperature and high-temperature paste as compared to reactive silver ink. As little as 16.4 mg of silver is consumed when a busbarless cell is metallized with reactive silver ink.

Importance of the Heat Treatment Scheme on Self-Reducing Reactive Silver Inks

Importance of the Heat Treatment Scheme on Self-Reducing Reactive Silver Inks

Numerical Simulation of Solvent Evaporation in a Reactive Silver Ink Droplet Deposited on a Heated Substrate.

Understanding the movement of silver ions (Ag+) in the solvent of a thermally evaporated particle-free reactive silver ink droplet is essential for optimizing the electronic inkjet printing process. In this work, a numerical study based on the Navier-Stokes equations is used to examine the microflows inside the evaporating solvent of a reactive silver ink droplet and to predict the morphology of the resultant Ag particle aggregations that form during the heat-activated processes. The droplet evaporation of the water-ethylene glycol ink solvent (H2O-(CH2OH)2) is simulated using COMSOL Multiphysics software. The model assumes that the evaporating fluid is heterogeneous due to the mass transfer of ethylene glycol molecules throughout the droplet by capillary flow. A layer of concentrated ethylene glycol forms at the fluid-substrate interface during solvent evaporation if the substrate is heated. The concentrated ethylene glycol molecules are then transported inward by the capillary action, and the resultant Ag particles, arising from the thermally driven reactions, accumulate at the bottom center of the drying droplet. The numerical simulations demonstrate that the droplet evaporation process depends on the water concentration in the solvent, substrate temperature, surface tension, and natural convection. Furthermore, the capillary flow dominates the fluid flow inside the evaporating droplet, causing some Ag particles to accumulate at the contact line, the commonly observed "coffee-ring effect". The results provide new insights into the chemical reactions that produce experimentally observed silver particle aggregations during the reactive silver ink droplet evaporation process and help establish realistic process parameters for improving the quality of inkjet-printed conductive silver films and electronic circuit microtraces.

Photocatalytic and bactericidal behaviors of Ag/TiO2 doped biochar through Ball–milling approach

Biochar materials derived from various biomass feedstocks have attracted considerable interest as high-performance sorbents for a wide range of contaminants in wastewater. However, the diligence and preoccupation in developing multifunctional materials with interesting properties has prompted researchers worldwide to consider the functionalization of pure biochar for more beneficial applications. In this study, for the first time, a novel ternary photocatalyst was successfully prepared from date palm rachis biochar (BDPR) and silver-doped titanium dioxide (Ag/TiO2) nanoparticles with different Ag/Ti weight ratios using a simple and environmentally friendly ball milling technique. The structural and physicochemical properties of the resulting photocatalysts were investigated by various characterization methods, namely X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA) and UV-diffuse reflectance spectroscopy (UV-DRS). The photocatalytic property of the photocatalysts was evaluated through the degradation of organic dyes, namely, methylene blue (MB) and Congo red (CR). The results show that the photocatalytic activity was greatly enhanced with increasing silver content compared to the neat and TiO2-doped biochars. Complete removal of methylene blue was achieved after 90 and 75 min for 5 %Ag/TiO2-BDPR and 10 %Ag/TiO2-BDPR, respectively, while it took 150 min for 100% photodegradation of Congo red. This was due to the synergistic effect of biochar, silver and TiO2 in trapping electrons and reducing the recombination of e-/h+ pairs. In addition, the photocatalysts could be regenerated and reused for up to 5 cycles without significant degradation of their properties. Furthermore, both 5% and 10% Ag/TiO2 BDPR photocatalysts exhibited high antibacterial activity against E. coli and S. aureus bacteria due to the combined effect of biochar as a sorbent, reactive oxygen species (ROS) and silver.

Silver Meshes for Record-Performance Transparent Electromagnetic Interference Shielding.

We present a simulation and experimental study of silver meshes to determine their performance for transparent electromagnetic interference (EMI) shielding. Simulations were employed to study the effects of the silver mesh's width, pitch, and thickness on EMI shielding efficiency (SE) in the 8-18 GHz frequency range and transparency in the visible spectrum. We demonstrate a scalable, facile fabrication method that involves embedding meshes in glass by etching trenches in glass and filling and curing reactive particle-free silver ink in these trenches. Our silver meshes achieve 58.4 dB EMI SE with 83% visible light transmission and 48.3 dB EMI SE with 90.3% visible transmission. The combination of high-conductivity silver, small widths (1.3 to 5 μm), and large thicknesses (0.5 to 2.0 μm) enables the best performance of metal meshes as well as single-sided shielding materials for transparent EMI shielding, as reported in the literature.

Stretchable and wash durable reactive silver ink coatings for electromagnetic interference shielding, Joule heating, and strain sensing textiles

In this paper, we demonstrate a highly conductive, stretchable, and wash-durable fabric for a variety of electronic textile applications such as electromagnetic interference (EMI) shielding, Joule heating, and strain sensing by utilizing a chemical etchant pretreatment that promotes covalent bonding, a reactive silver ink with conformal in situ silver reduction, and the use of a polymer coating for a protective barrier. Reactive ink coated on polyethylene terephthalate (PET) knitted textiles exhibit an average EMI shielding efficiency of 74.8 dB in the X band (frequency range of 8–12 GHz) and 76.6 dB in the Ku band (12–18 GHz). The conductive textiles show high Joule heating performance, where a temperature of 152 °C can be achieved at only 1.3 V DC applied voltage. This Joule heating performance is maintained after stretching and washing. Furthermore, the textile may be used for strain sensing and monitoring human movement. As prepared silver films do not degrade after 1000 stretching cycles at 50 % strain and maintain EMI SE higher than 70 dB after 300 min washing. The demonstrated textiles may be used for wearable electronics, personal medical devices, and next generation communications.

Investigation of Reactive Silver Ink Formula for Reduced Silver Consumption in Silicon Heterojunction Metallization

Silver is the most expensive non-silicon component in photovoltaic cells. This is particularly salient for silicon heterojunction (SHJ) cells, which rely on large quantities of low-temperature silver pastes (LT-SP). SHJ cells would benefit greatly from an industrially scalable metallization process that simultaneously offers low silver consumption, low finger resistivities (<20 μΩ·cm), and low processing temperatures. Printed reactive silver inks (RSI) are an innovative candidate to this end. This work furthers the research on RSI metallization by investigating the impact of ink formula on properties pertinent to SHJ cells, including electrical properties, line width, ink splatter, silver consumption, cell performance, and adhesion. We introduce a scalable, high-throughput flexible needle contact printing approach for metallization that solves many of the issues associated with drop-on-demand printing. The printed silver fingers are characterized using electrical measurements and top-down and cross-sectional microscopy. The best performing ink, consisting of silver acetate, ethylamine, and formic acid, achieved silver fingers with total resistivities of 3.1 μΩ·cm and contact resistivities of 3.2 mΩ·cm2 when printed at 61 °C. This ink metallized a full-sized 156 mm × 156 mm SHJ cell. This is the first reported data for RSI metallization of a full-sized SHJ cell and shows how an optimized RSI can achieve similar performances to LT-SP while consuming 80–90% less silver.

Preparation of Ag–Fe2O3-Based black and electrically insulating coatings by magnetron sputtering from metal targets

Black and electrically insulating coatings provide touch panel displays with a classic appearance. In this study, black and electrically insulating Ag–Fe2O3-based coatings were prepared using reactive magnetron sputtering, stainless steel and silver foil. The thin films prepared with oxygen introduction and no Ag foil showed blue light absorption and high electrical resistance, which are comparable to those of Fe2O3 single crystals. The optimal Ag foil size for maintaining a high electrical resistivity of 108 Ω·sq−1 was determined to be 54 mol%Ag in the film samples. Black and electrically insulating thin films composed of metallic Ag, amorphous Ag–Fe–O, and slightly crystallized Fe2O3 were prepared using 3.4 or 3.9 %O2. Metallic Ag segregated randomly in the high-refractive-index Fe2O3-based matrix, resulting in plasmonic absorption over a wide range of wavelengths centered in the red-wavelength region. At 3.9 %O2, a high sheet resistance of 108 Ω·sq−1 and strong visible absorption of 35.2 μm−1 (on average), slightly deviating by 2.4 μm−1 were simultaneously achieved by clear phase separation of the Ag grains and Fe2O3-based matrix. A clear phase separation mechanism based on thermodynamic nonequilibrium oxidation of the metallic Ag phase is proposed.

All-atmospheric fabrication of Ag–Cu core–shell nanowire transparent electrodes with Haacke figure of merit >600 × 10–3 Ω−1

Transparent conducting electrodes (TCEs) are essential components in devices such as touch screens, smart windows, and photovoltaics. Metal nanowire networks are promising next-generation TCEs, but best-performing examples rely on expensive metal catalysts (palladium or platinum), vacuum processing, or transfer processes that cannot be scaled. This work demonstrates a metal nanowire TCE fabrication process that focuses on high performance and simple fabrication. Here we combined direct and plating metallization processes on electrospun nanowires. We first directly metallize silver nanowires using reactive silver ink. The silver catalyzes subsequent copper plating to produce Ag–Cu core–shell nanowires and eliminates nanowire junction resistances. The process allows for tunable transmission and sheet resistance properties by adjusting electrospinning and plating time. We demonstrate state-of-the-art, low-haze TCEs using an all-atmospheric process with sheet resistances of 0.33 Ω sq−1 and visible light transmittances of 86% (including the substrate), leading to a Haacke figure of merit of 652 × 10–3 Ω−1. The core–shell nanowire electrode also demonstrates high chemical and bending durability.

Rapid Biotransformation of Luminescent Bimetallic Nanoparticles in Hepatic Sinusoids.

Liver sequestration, mainly resulting from the phagocytosis of mononuclear phagocyte system (MPS) cells, is a long-standing barrier in nanoparticle delivery, which severely decreases the disease-targeting ability, leads to nanotoxicity, and inhibits clinical translation. To avoid long-term liver sequestration, we elaborately designed luminescent gold-silver bimetallic nanoparticles that could be rapidly transformed by the hepatic sinusoidal microenvironment rich in glutathione and oxygen, significantly different from monometallic gold nanoparticles that were rapidly sequestrated by Kupffer cells due to the much slower biotransformation. We found that the rapid sinusoidal biotransformation induced by the synergistic reactions of glutathione and oxygen with the reactive silver atoms could help bimetallic nanoparticles to avoid MPS phagocytosis, promote fast release from the liver, prolong blood circulation, enhance renal clearance, and increase disease targeting. With the fast biotransformation in sinusoids, liver sequestration could be turned into a beneficial storage mechanism for nanomedicines to maximize targeting.

Hydrocortisone을 담지한 Chitosan silver nanoparticles의 약물흡수 및 방출

The final goal of this research was to improve a treatment for allergy rhinitis using chitosan-hydrocortisone silver nanoparticles based on hydrocortisone-deposited chitosan. The nanoparticles were produced by depositing hydrocortisone in chitosan, generating a reaction with highly reactive silver, and placing the nanoparticles into the nasal mucosa. Silver nanoparticles were manufactured after chitosan deposition and the optimal hydrocortisone concentration supporting the highest drug delivery efficiency was identified. For efficient DDS(Drug Delivery Systems applications, an adsorption experiment was performed before silver nanoparticle production according to the hydrocortisone concentration. In addition, a release experiment with different amounts of silver salt was performed to determine the optimal hydrocortisone and silver salt concentrations for producing chitosan-hydrocortisone silver nanoparticles. The amount released was investigated as a parameter of time. When the hydrocortisone concentration was 0.05g, the chitosan adsorption rate was highest at 48%. A release experiment was conducted at 36℃ in PBS, which is similar to the human body condition, while changing the silver salt amount. At approximately 60 hours, the absorbance was constant, indicating that hydrocortisone was emitted from the chitosan particles. In the cases of the 50㎕ reaction and 100㎕ reaction, the release rate was 14.17% and 12.92%, respectively. Otherwise, in the case of using 10㎕ silver salt solution for the reaction, 99.6% of the amount absorbed was released, showing the highest efficiency as a drug delivery agent.

Reactive silver inks for antiviral, repellent medical textiles with ultrasonic bleach washing durability compared to silver nanoparticles.

Medical textiles are subject to particularly harsh disinfection procedures in healthcare settings where exposure risks are high. This work demonstrates a fabric treatment consisting of a reactive silver ink and low surface energy PDMS polymer that provides for superhydrophobicity and antiviral properties against enveloped herpes simplex virus stocks even after extended ultrasonic bleach washing. The antiviral properties of reactive silver ink has not been previously reported or compared with silver nanoparticles. The fabric treatment exhibits high static contact angles and low contact angle hysteresis with water, even after 300 minutes of ultrasonic bleach washing. Similarly, after this bleach washing treatment, the fabric treatment shows reductions of infectious virus quantities by about 2 logs compared to controls for enveloped viruses. The use of silver ink provides for better antiviral efficacy and durability compared to silver nanoparticles due to the use of reactive ionic silver, which demonstrates more conformal coverage of fabric microfibers and better adhesion. This study provides insights for improving the wash durability of antiviral silver fabric treatments and demonstrates a bleach wash durable, repellent antiviral treatment for reusable, functional personal protective equipment applications.

Fully 3D printed high performance band-stop filters enabled by three-dimensional design

Additive manufacturing enables the production of high performance radio frequency device components, but most printable materials are plagued by large losses that render them impractical for robust performance applications beyond rapid prototyping. Here, we demonstrate a set of fully three-dimensional (3D) printed band-stop filters fabricated by printing reactive silver ink onto three different additively manufactured resin substrates with varying dielectric properties. Each of the dielectric substrates were fabricated using stereolithography or digital light processing printing methods. By switching from a dielectric with tanδ = 0.06 to one with tanδ = 0.0073, we can decrease the total loss present in the structure by up to 2 dB. As enabled by 3D additive manufacturing, we also show that regardless of the dielectric material, moving from two-dimensional planar patterns to fully-3D topographies allows us to simultaneously widen the filter stopband by 2 GHz and theoretically increase signal rejection by up to 30 dB. This demonstration of a fully additively-manufactured, 3D band-stop filter that closely matches simulations represents a new class of device construction that was previously inaccessible using only 2- and 2.5-D manufacturing techniques.

Morphological Regulation of Printed Low-Temperature Conductive Ink.

The unbalanced evaporation of solvents in low-temperature sintered inks for printed electronics leads to a series of problems in the actual printing process, including printed pattern distortion, surface cracking, and the coffee ring effect, which has become a serious obstacle to this technique. Here, we present a comprehensive investigation of the influence of the solvent composition, environmental, and sintering conditions on the complicated pattern formation process of reactive silver inks. The results first showed that only inks with a certain wettability of solvents could form well-defined patterns. Then, the solvent composition and ambient humidity can be adjusted to balance the nonequilibrium evaporative flow within the liquid and thus to obtain a flat liquid film. Combined with the rapid UV sintering process, the particle size, porosity, and roughness could be controlled to produce dense and homogeneous silver films. Finally, we successfully printed silver electrodes with a smooth and dense surface (Rqs ∼ 21 nm in 0.8 × 0.8 mm2 area and less than 1% porosity) under an optimized relative humidity (RH) of 50-60% at room temperature with the solvent composition of IPA (isopropanol)/2,3-BD (2,3-butanediol) = 8:2. In addition, we also demonstrated high-performance Pr-IZO (praseodymium-doped indium-zinc oxide) thin film transistors (TFTs) with a mobility (μsat) of 2.14 cm2/V/s and Ion/Ioff ratio of over 107 using source-drain electrodes printed under optimized conditions.

Achieving Highly Conductive, Stretchable, and Washable Fabric from Reactive Silver Ink and Increased Interfacial Adhesion

Achieving Highly Conductive, Stretchable, and Washable Fabric from Reactive Silver Ink and Increased Interfacial Adhesion