Addition Of Ag Research Articles

Enhancing Supercapacitor Performance of NiCoMn‐Layered Double Hydroxide with Ag–Citrate/Polyaniline Nanocomposites

Layered double hydroxide (LDH) has a layered structure, which makes it a strong candidate for supercapacitors (SC) due to its high surface area. However, they suffer from low conductivity due to insufficient charge transfer across their layers. This research aims to overcome this obstacle by introducing conductive channels among the layers by the addition of Ag–citrate and polyaniline (PANI). Consequently, five electrodes (S1–5) were made from NiCoMn LDH (referred to as LDH henceforth) and 2:1 Ag–citrate and PANI composite (Ag/PANI) in different ratios and made into electrodes. Electrochemical analysis revealed successful improvement in the performance of LDH as the fraction of Ag/PANI increased until it equaled Ag/PANI where the highest specific capacitance of 617 F g−1 was obtained, which is 12% greater than the value for solely LDH electrode (550 F g−1). A device was fabricated with the best electrode (S3) and activated carbon electrode, which demonstrated energy densities and power densities of 41 WhKg−1 and 412.5 W Kg−1 and 14 WhKg−1and 8250 W Kg−1 at 0.5 and 10 A g−1 current densities, respectively. It also exhibited a capacitive retention of about 75% at 3000 galvanostatic charge–discharge cycles. These results encourage the use in of NiCoMn LDH, in a 1:1 ratio with Ag/PANI in SCs due to its remarkable performance.

Reduction of 4‐Nitrophenol Catalyzed by Gold Nanoclusters with Aggregation‐Induced‐Emission: Emission Intensity Correlated Activity and Mechanistic Exploration

AbstractThiolate‐protected Au nanoclusters (NCs) have developed as a promising class of model catalysts to achieve fundamental understanding of metal nanocatalysis. Whereas, the packing mode of peripheral ligand on metal core is changeful in the reaction medium and show elusive impact on catalytic activity. In this work, using glutathione (GSH) protected Au NCs (Au@GSH NCs) with aggregation‐induced‐emission (AIE) characteristics as model catalyst for the hydrogenation of 4‐nitrophenol (4‐NP), photoluminescence (PL) intensity correlated catalytic activity of Au@GSH NCs was successfully mediated by the addition of Ag+ in the preparation or poor solvent in the reaction medium, showing a relationship of “as one falls, another rises.” Au NCs with intense PL implied a dense packing of peripheral ligand, which hampered the accessibility of active site and thus exhibited slowest catalytic reaction kinetics of the reduction of 4‐NP and vice versa. Based on this methodology, a case study of the effect of salt additives on the catalytic activity is carried out, different mechanisms are distinguished by the change in the PL intensity, and with the combination of diagnostic deuterium isotope experiments, it has been demonstrated that the proton from water solvent is involved in the reaction and that the proton transfer process is the rate‐determining step, the contribution of ionic additives to the hydrogen bonding network determines their effect on the reaction kinetics. The correlation between PL intensity and catalytic activity of Au NCs could provide an efficient way to design highly active Au NC catalysts and give a new insight to understand the unique optoelectronic properties of Au NCs and reaction mechanism.

Detection of Silver and Mercury Ions Using Naphthalimide-Based Fluorescent Probe.

A multifunctional fluorescent probe P based on a naphthalimide derivative for the detection of Ag+ and Hg2+ through a dual-signal was designed and characterized. P exhibited a large Stokes shift (107 nm), high selectivity, good sensitivity, and fast response time. By adjusting the testing medium and the order of reagent addition, multifunctional detection with P was achieved. The addition of Ag+ or Hg2+ to P solution in either ethanol or an ethanol-water mixture resulted in a significant quenching of fluorescence emission at 537 nm and caused a decrease in the absorbance at 440 nm accompanied by the appearance of a new absorption peak at around 340 nm, and there was an obvious color change from yellow to colorless. In contrast, the addition of other common metal ions and anions did not produce substantial spectral or color changes. The detection limit of probe P for Ag+ and Hg2+ was calculated to be 0.33 μM. The sensing mechanism was proposed and validated through MS and 1H NMR spectrometry methods. Additionally, P demonstrated the capability to recognize Ag+ and Hg2+ in living cells with satisfactory results.

Impact of plasmonic silver on the perovskite Bi9Ti6FeO27: Removal of tetracycline and antimicrobial activity

The synthesis, characterization, photocatalytic, and antibacterial analysis of plasmonic Ag- loaded Bi9Ti6FeO27 at various concentrations of Ag are presented in this study. The synthesis of Ag/Bi9Ti6FeO27 is based on the impregnation of different weight percentages of Ag (20, 50, and 80) on Bi9Ti6FeO27. The XRD and HRTEM result shows that the perovskite Bi9Ti6FeO27 maintained orthorhombic crystallinity having space group Pnm (No.62). Upon addition of Ag, do not disturb the crystallinity of Bi9Ti6FeO27. XPS analysis displays the valence states and surface chemical composition of the as-prepared Ag/Bi9Ti6FeO27. All the composites exhibit good UV–visible absorbance in the range of 200–800 nm, and the band-gap energy gradually decreases from 3.30 eV to 2.73 eV with an increase in silver content. The photocatalytic degradation of 40 ppm tetracycline is examined at 120 min at neutral pH (7). Loading of Ag on Bi9Ti6FeO27 significantly promoted the photocatalytic degradation efficiency of tetracycline (84 %). Furthermore, the antibacterial activity of Ag/Bi9Ti6FeO27 was investigated against “Escherichia coli”, Klebsiella pneumoniae”, and “Acinetobacter baumannii” bacteria. Higher loading of Ag on Bi9Ti6FeO27 exhibited the most potent antibacterial activity by effectively inhibiting the growth of both bacterial strains through reactive oxidative species and the presence of silver nanoparticles. The composite has proved its stability through the five repeated cycles. This work provides an emerging strategy to finely design the nanocomposites and highlight their potential for environmental remediation and healthcare industries.

Synergistic effects of Ag and Sc addition on superior thermal stability in Al-Mg-Si-Cu alloy

Al-Mg-Si-Cu-Ag-Sc alloy with superior thermal stability has been designed, and a new mechanism for enhancing thermal stability was suggested in this study. The complex addition of Ag and Sc and the increased Cu content significantly enhanced the thermal stability of the Al-Mg-Si-Cu alloy by preventing the growth of over-aged precipitates. Particularly, Ag addition only delayed hardness degradation at the over-aging stage, whereas Sc addition lowered both the precipitation kinetics during the early and over-aging stages. The different roles of Ag and Sc create a synergistic effect so that excellent thermal stability can be obtained by the complex addition of Ag and Sc. The role of Ag in enhancing thermal stability generally depends on the conventional mechanisms of disordering and solute segregation. However, since the amount of Sc detecting was too low to have a sufficient influence on the thermal stability of the precipitate, the presence of Sc solute in the matrix was predicted. Solute analysis of the matrix revealed that Sc enhanced the thermal stability by disturbing Cu diffusion to Cu-containing precipitates. The strong Sc-Cu interaction enabled the temporary catching of Cu atoms by forming an Sc-Cu pair. Therefore, Sc not only enhances thermal stability but also delays age-hardening kinetics because the formation of Cu-containing precipitates is disturbed by the delaying mechanism depending on Sc-Cu pair formation. Additionally, the observation that the complex addition of Ag and Sc accelerated the formation of Mg-rich clusters during early stage aging provides minor evidence for the enhanced thermal stability of the Ag-Sc added Al-Mg-Si-Cu alloy. This is because Mg-rich clusters may be related to precursors of Cu-containing precipitate due to their high Cu contents and high Mg composition of Q′ and L phases.

Effect of trace silver addition on microstructure and properties of Cu-0.45Cr-0.1Zr alloy

Cu-0.45Cr-0.1Zr-(0.3Ag) were produced and subjected to multistage thermo-mechanical treatment. The microstructure evolution and properties of the alloys during aging were investigated in detail and the effect of trace Ag on comprehensive properties of Cu-Cr-Zr alloy was discussed by kinetic and strength calculations. The results showed that Cu-0.45Cr-0.1Zr-0.3Ag alloy had a higher strength than Cu-0.45Cr-0.1Zr alloy while maintaining a high electrical conductivity. After multistage thermo-mechanical treatment, the tensile strength, yield strength and electrical conductivity of Cu-0.45Cr-0.1Zr-0.3Ag alloy reached 611MPa, 601MPa and 78.7 %IACS, respectively. The addition of Ag had little influence on the precipitation process of Cu-Cr-Zr alloy during aging: Cr particles transitioned from GP zones to face-centered cubic (fcc) structure and finally stabilized in body-centered cubic (bcc) structure, however, the composition of Zr precipitates changed after Ag doping. Most of Zr atoms segregated at grain boundaries in the form of Cu4AgZr in Cu-0.45Cr-0.1Zr-0.3Ag alloy instead of Cu5Zr in Cu-0.45Cr-0.1Zr alloy. The calculation results showed that the addition of Ag refined the size of Cr particle, increased the density of dislocations, enhanced the effect of dislocation strengthening.

Effect of Ag addition on the mechanical properties of Cu/Ni/Sn/Ni/Cu microbump with a sub-10 micron bump thickness

Effect of Ag addition on the mechanical properties of Cu/Ni/Sn/Ni/Cu microbump with a sub-10 micron bump thickness

The Influence of Ag Addition and Different SiO2 Precursors on the Structure of Silica Thin Films Synthesized by the Sol-Gel Method.

In this work, the structure of silica thin films synthesized with three different SiO2 precursors and obtained by the sol-gel method and dip coating technique was studied. Additionally, the influence of Ag addition on the obtained silica sols and then gel structure was investigated. Silica coatings show antireflective properties and high thermal resistance, as well as hydrophobic or hydrophilic properties. Three different silica precursors, TEOS (tetraethylorthosilicate), DDS (dimethyldietoxysilane) and AerosilTM, were selected for the synthesis. DDS added to silica sol act as a pore size modifier, while Ag atoms are known for their antibacterial activity. Coatings were deposited on two different substrates: steel and titanium, dried and annealed at 500 °C in air (steel substrate) and in argon (titanium substrate). For all synthesized films, IR (infrared) spectroscopic studies were performed together with GID and XRD (Grazing Incidence Diffraction, X-ray Diffraction) measurements. The topography and morphology of the surface were traced by SEM and AFM microscopic methods, providing information on the samples' roughness, particle sizes and thickness of the particular layers. The wetting angle values were also measured. GID and XRD measurements pointed to the distinct contribution of an amorphous phase in the samples, allowing us to recognize the crystalline phases and calculate the silver crystallite sizes. The FTIR spectra gave information on the first coordination sphere of the studied samples.

Thermodynamic and Kinetic Properties of the Lithium-Silver System.

A carbon-silver anode has recently been shown to suppress dendrite formation in all-solid-state lithium-ion batteries. The role that silver plays in enabling the reversible deposition and stripping of lithium remains unknown. Furthermore, very little is known about the thermodynamic and kinetic properties of Li x Ag1-x alloys. Here, we report on an in-depth first-principles study of phase stability and diffusion mechanisms in the Li-Ag alloy system. We identify two new intermetallic phases that are predicted to be stable in Li-rich Li x Ag1-x alloys with stoichiometries of Li3Ag and Li11Ag2. Our calculations show that the peculiar and highly anharmonic energy surface of pure Li along the Bain and Burgers paths persists upon the addition of Ag to BCC Li. This has important implications for room-temperature phase stability and mechanical properties. We have also performed a systematic study of diffusion mechanisms in the Li x Ag1-x alloy system as a function of alloy concentration x. Diffusion in alloys and intermetallics is mediated by vacancies. High vacancy formation energies are predicted in the Li x Ag1-x alloy, especially in Ag-rich FCC solid solutions. Complex diffusion mechanisms are identified in the B2 and γ-brass intermetallic phases that include two-atom hops and second-nearest neighbor hops. The migration barriers are found to decrease with increasing Li concentration, with predictions of exceptionally low migration barriers of 0.1 eV in the D03 Li3Ag phase.

Role of Ag Addition on the Microscopic Material Properties of (Ag,Cu)(In,Ga)Se2 Absorbers and Their Effects on Losses in the Open‐Circuit Voltage of Corresponding Devices

ABSTRACTAg alloying of Cu(In,Ga)Se2 (CIGSe) absorbers in thin‐film solar cells leads to improved crystallization of these absorber layers at lower substrate temperatures than for Ag‐free CIGSe thin films as well as to enhanced cation interdiffusion, resulting in reduced Ga/In gradients. However, the role of Ag in the microscopic structure–property relationships in the (Ag,Cu)(In,Ga)Se2 thin‐film solar cells as well as a correlation between the various microscopic properties of the polycrystalline ACIGSe absorber and open‐circuit voltage of the corresponding solar cell device has not been reported earlier. In the present work, we study the effect of Ag addition by analyzing the differences in the various bulk, grain‐boundary, optoelectronic, emission, and absorption‐edge properties of ACIGSe absorbers with that of a reference CIGSe absorber. By comparing thin‐film solar cells with similar band‐gap energies ranging from about 1.1 to about 1.2 eV, we were able to correlate the differences in their absorber material properties with the differences in the device performance of the corresponding solar cells. Various microscopic origins of open‐circuit voltage losses were identified, such as strong Ga/In gradients and local compositional variations within individual grains of ACIGSe layers, which are linked to absorption‐edge broadening, lateral fluctuations in luminescence‐energy distribution, and band tailing, thus contributing to radiative VOC losses. A correlation established between the effective electron lifetime, average grain size, and lifetime at the grain boundaries indicates that enhanced nonradiative recombination at grain boundaries is a major contributor to the overall VOC deficit in ACIGSe solar cells. Although the alloying with Ag has been effective in increasing the grain size and the effective electron lifetime, still, the Ga/In gradients and the grain‐boundary recombination in the ACIGSe absorbers must be reduced further to improve the solar‐cell performance.

Restriction of reaction sites on metal-sulfide cores induced by steric repulsion of bis-N-heterocyclic carbene ligands in trinuclear complexes bearing triply bridging sulfide ligands.

Mixed-ligand and mixed-metal trinuclear complexes bearing two {Pt-bisNHC-C1} moieties, [{Pt(bisNHC-C1)}2(ML)(μ3-S)2] n+ (ML = Pt(bisNHC-C2), n = 2; ML = Pt(bisNHC-C3), n = 2; ML = Rh(cod), n = 1; ML = RhCp*, n = 2), where bisNHC-C1, bisNHC-C2 and bisNHC-C3 represent methylene-, ethylene- and propylene-bridged bis-NHC ligands, respectively, were synthesised and structurally characterised. Reactions of these complexes with a half eq. of Ag(i) ions were examined using 1H and 195Pt NMR spectroscopy. The results exhibit that the trinuclear complexes react with Ag(i) ions accompanied by the formation of Ag-Pt bonds with the {Pt-bisNHC-C1} moieties in the first step affording corresponding heptanuclear complexes except for the RhCp* complex. The RhCp* complex gave a tetranuclear complex bearing the trinuclear unit with an Ag(i) ion. Further addition of Ag(i) ions for the other complexes resulted in disassembling of the heptanuclear clusters affording tetranuclear complexes confirmed by the observation of exchange of the Ag(i) ions in 195Pt NMR measurements, which exhibited signals with no coupling to Ag nuclei.

Improved electrochemical performance of Ag-modified Bi0.7Sr0.3FeO3 cathodes by electroless plating for intermediate-temperature solid oxide fuel cells

The Bi0.7Sr0.3FeO3-δ (BSFO)-Ag composite cathode is prepared by modifying BSFO with in-situ chemical plating of Ag. The plated Ag effectively reduces the polarization resistance (Rp) of BSFO. At the Ag loading of 20 wt.%, the optimized Rp of BSFO at 650oC in air condition is 0.35 Ω cm2, which is only 18.6% of that of BSFO cathode (1.88 Ω cm2). The electrochemical performance improvement is primarily attributed to the low oxygen adsorption energy (Eads) domain at the interfaces of BSFO-Ag, as indicated by the first-principles calculations (Eads, -0.81eV). Thus, the addition of Ag changes the cathodic reaction rate control step from the molecular oxygen on the cathode surface adsorption and diffusion to charge transfer on the cathode. The maximum power density (Pmax) of the prepared single cell at 650oC is 450.98 mW cm-2 using H2 (∼3 vol.% H2O) as fuels. The open-circuit voltage (OCV) does not decay significantly (around 0.66 V) after 50 h at the current density of 400 mA cm-2, showing good long-term stability.

A novel all-solid-state Z-scheme BiVO4/Ag/Cu2O heterojunction: Photocatalytic and photothermal synergistic catalysis of tetracycline under simulated sunlight irradiation

The possible hazards posed by tetracycline (TC) to the environment and public health have made it a critical concern. In this work, the all-solid-state Z-scheme heterojunction BiVO4/Ag/Cu2O nanocomposites (NCs) were synthesized through a hydrothermal approach for the purpose of achieving efficient degradation towards TC. BiVO4/Ag/Cu2O NCs were able to efficiently degrade TC when exposed to simulated sunlight. The results showed that the photocatalytic efficiency was significantly influenced by Cu2O and Ag nanocrystals. The presence of Ag with large light absorption capability facilitated the efficient electron (e-) transfer between BiVO4 and Cu2O nanocrystals, thereby expanding the spectral range of light absorption in BiVO4/Cu2O NCs. Under photocatalytic and photothermal synergistic conditions, BiVO4/Ag/Cu2O NCs with an optimal addition of Ag were able to degrade TC within 60 min at reaction rate constant (k) of 0.04816 min−1. It was discovered that the best-performing photocatalysts (BAC-2) achieved photothermal conversion rates as high as 27.9 %, and they could exhibit outstanding photocatalytic and photothermal efficiency even after six cycles. Furthermore, the results obtained in radical trapping experiments suggested that photogenerated holes (h+), electrons (e-), superoxide radicals (·O2-), hydroxyl radicals (·OH) and singlet oxygen (1 O2) were involved in the photocatalytic degradation of TC. In the context of practical application, the effects of different initial TC concentrations and different irradiation conditions were studied in depth. In addition, the all-solid-state Z-scheme heterojunction mechanism for degrading TC was put forward. This research endeavors to broaden the application scope of all-solid-state Z-scheme heterojunction photocatalysts, with the aim of achieving significantly improved photocatalytic degradation of antibiotic pollutants.

A fluorescence turn-on organosilane-coated Cyst/QDs nanocomposites for highly sensitive and selective monitoring silver ions in living organisms

The practical applications of Cd-based quantum dots (QDs) in biological systems have been restricted by their high toxicity and poor biocompatibility. Herein, we constructed a new water-soluble Cyst/QDs nanocomposites composed of silicon-functionalized CdSe/CdS QDs and cystine as a turn-on fluorescent probe for the imaging and detection of Ag+ in living organisms. CdSe/CdS-Si-NH2 QDs with rich amino groups (-NH2) on their surface were firstly synthesized by reacting 3-aminopropyltrimethoxysilane with CdSe/CdS QDs capped with 2-mercaptoethanol. CdSe/CdS-Si-NH2 QDs emit the bright green fluorescence at 575 nm in aqueous solution with quantum yield of 10.6 % and superior photo-stability. Meanwhile, their fluorescence intensity can be effectively enhanced by cystine based on its strong affinity towards Cd2+ on the surface of Cd-based QDs. Besides, the addition of Ag+ results in a strongly enhanced fluorescence of as-prepared Cyst/QDs nanocomposites in aqueous solution. Under the optimal conditions, the response was linearly proportional to natural logarithm of Ag+ concentration ranging from 4.0×10−9 to 1.0×10−6 mol/L with a detection limit of 1.65 nM. Furthermore, Cyst/QDs nanocomposites can be exploited as a possible fluorescent probe for in vivo imaging based on its excellent luminescent properties, low toxicity and great biocompatibility. Bio-imaging study also revealed that Cyst/QDs nanocomposites could be applied to detecting Ag+ in live cells and organisms (zebrafish). Thus, our research provides an efficient method for creating low-toxic and biocompatible Cd-based QDs nanoprobe for a sensitive and selective detection of Ag+ in live cells and organisms.

Thiazole-derived pyrazin-2-carbohydrazide chemosensors: Colorimetric & photoluminescent detection of silver ions for theoretical, environmental, and cell imaging

In this work, a simple and versatile chemosensor receptor TZPYZ was synthesized through the combination of thiazole with pyrazine-2-carbohydrazide, resulting in a confirmed chemical structure via various analytical techniques including FT-IR, 1H, and 13C Nuclear Magnetic Resonance Spectroscopy, as well as High-Resolution Mass Spectroscopy analysis. TZPYZ exhibits specific colorimetric and photoluminescent responses to Ag+ ions in a solvent solution consisting of DMSO and H2O (7:3, v/v). Upon addition of Ag+ ions, noticeable changes in absorption spectra occur, resulting in a visible color change from pale yellow to blue. Additionally, an enhanced emission intensity with wavelength at 523 nm, when excited at 410 nm. Notably, TZPYZ demonstrated exceptional selectivity for Ag+ ions over other metal cations, achieving a detection limit (LOD) of 10.6 × 10−9 M and 6.74 × 10−9 M and using the UV–visible & photoluminescent titration method. Interference studies indicated minimal disruption from other metal ions on emission at 523 nm, highlighting TZPYZ discerning capability for Ag+ ions. With a binding affinity of 3.622 × 10−11 M−1, TZPYZ proved effective in detecting Ag+ ions across various water samples, showcasing its practical utility. The mechanism of interaction between TZPYZ and Ag+ ions was investigated using various experimental techniques, including Job’s plot, Benesi-Hildebrand investigations, 1H NMR, and HRMS analysis. Test strips coated with TZPYZ showed selective detection of Ag+ ions, indicating its potential for on-site applications. Furthermore, DFT computations provided insights into the structural and electronic properties of TZPYZ and its complex with Ag+ ions, further elucidating the binding mechanism and stability of the complex. In addition, TZPYZ demonstrated compatibility with biological systems, as fluorescence imaging tests on MCF-7 breast cancer cells confirmed both its non-cytotoxic nature and its proficiency in detecting intracellular silver ions. Based on these findings, TZPYZ is highlighted as a highly sensitive and selective chemosensor for Ag+ ions, with promising applications in environmental analysis and bioimaging.

A colorimetric Ag+ chemosensor based on a cyclometalated ruthenium complex with deprotonated 2-phenylbenzimidazole

A cyclometalated ruthenium complex (1) using 2-phenylbenzimidazole as a C,N-ligand was developed as a colorimetric chemosensor to detect Ag+ ions. Upon the addition of Ag+ ions, the absorption spectra of complex 1 demonstrated no change in CH3CN solution. However, an excellent solution color change from dark-green to purple and absorption spectral change with a blue-shift of 27 nm (from 612 to 585 nm) were clearly observed after Ag+ ions were added to the solution of 1 with 2-fold of fluoride (denoted as 1 + F−). When Ag+ ions were replaced by other common metal ions, the solution color changed from green to red. Therefore, the solution of 1 + F− can be used to distinguish Ag+ from the other common metal ions. The absorption intensity at 612 nm exhibited a good linear correlation for the detection of Ag+ ion from 0 to 4 µM with a detection limit of 0.34 µM. According to the absorption and 1HNMR spectral changes of complex 1, the reaction mechanism is proposed to be as a coordination between silver ion and the deprotonated nitrogen in imidazole. However, the interactions of other metal ions with 1 + F− are related to a proton transfer process.

One-step combustion synthesis of high-performance nanosized Co3O4 and Ag-Co3O4 catalysts for propane total oxidation

Devising an effective strategy to refine the physicochemical properties of Co3O4 and tune the Ag-Co interaction is pivotal for developing superior Ag-Co3O4 catalysts targeting VOCs abatement. In this study, nanosized Co3O4 and Ag-Co3O4 (Ag content of 0.5–5.0 wt%) catalysts were prepared via a facile one-pot urea combustion method. The as-prepared catalysts were characterized using various techniques and their performance in propane total oxidation was evaluated. Compared to its counterpart obtained through the direct decomposition of cobalt nitrate, the nanosized Co3O4 exhibited a larger surface area, more oxygen vacancies, better reducibility, and thus superior propane oxidation activity. The addition of Ag can further enhance the catalytic performance by significantly improving the redox properties of Co3O4. The best performance was achieved with the catalyst 3.5 wt% Ag-Co3O4, which mineralized 90 % of propane into CO2 at 200 °C and exhibited excellent cycling stability and long-term durability. In addition, 3.5 wt% Ag-Co3O4 demonstrated high activity under various conditions, including high propane concentration (6000 ppm), high space velocity (160,000 mL g−1h−1), and high water content (10 vol%), making it a promising candidate for practical VOCs removal.

Enhanced Mechanical Properties with Ag Addition in Electroplated Ni-Sn Solder Joints: Sub-10 Micron Bond Thickness

Keywords: Micro-bump; Microstructure; Intermetallic compounds; Mechanical properties; thermocompression bondingThe advancement of electronic devices has garnered more extensive attention towards three-dimensional integrated circuit (3D-IC) technology due to microbump size reduction and increased power density. Microbumps play an important role in driving the development of this technology, especially in 3D chip-stacking involving multiple reflow processes. The reduction in microbump height spotlights the presence of intermetallic compounds (IMCs). In comparison to traditional ball grid array (BGA) solder joints, microbumps with smaller solder volumes exhibit a predominant fraction of IMCs at solder joints, especially with microbump dimensions potentially shrinking to less than 10 micrometers.The interface reaction within confined spaces has become a critical concern. Mechanical properties will be dominated by IMC properties rather than solder characteristics. In conventional Cu/Sn/Cu solder joints, grain coarsening and prolonged reflowing times, which result in IMC collisions from opposing substrates, forming columnar grains with a uniform orientation, make the solder joint less reliable. Furthermore, the Cu3Sn layer in Cu/Sn/Cu microbumps presents another challenges, indicating the formation of Kirkendall voids, increasing the risk of brittle interface fractures.This study investigates the mechanical reliability and microstructure of two sub-10um sandwiched structures: Cu/Ni/Sn/Ni/Cu and Cu/Ni/Sn-3.5Ag/Ni/Cu. In the 3D-IC manufacturing process, solder joints will experience multiple reflow processing. Different reflow heat treatment process to achieve different fractions of Ni3Sn4 IMCs were performed on both sandwiched structure. Despite the formation of internal voids due to volume shrinkage in Ni/Sn solder joints, the addition of silver in the solder, forming Ag3Sn, effectively fills these voids. The long-time reflowed sample showed outstanding mechanical properties via the addition of silver in solder. In this study, the influence of silver addition on the microstructure and mechanical properties of the overall joints under identical reflow conditions, the fracture path observation after shear test were investigated. The growth mechanism of Ag3Sn and its distribution in the solder would be further explored and addressed. Figure 1

Advancing self‐healing soy protein hydrogel with dynamic Schiff base and metal‐ligand bonds for diabetic chronic wound recovery

AbstractTo address the unique challenges of diabetic wound healing, wound dressings, particularly multifunctional hydrogels have garnered considerable interest. For the first time, a novel environmentally friendly soy protein‐based hydrogel is developed to accelerate the healing of diabetic chronic wounds. Specifically, this hydrogel framework is in direct formation through the dynamic Schiff base between oxidized guar gum and epigallocatechin‐3‐gallate (EGCG)‐modified soy protein isolate. Meantime, the addition of Ag+ enhances the cross‐linking of the hydrogel network by forming metal‐ligand bonds with the catechol groups in EGCG. Interestingly, the stretchability (up to 380%), swelling, and rheology properties of the hydrogel can be controlled by fine‐tuning the density of metal‐ligand bonds, endowing them with a high potential for precise matching. Additionally, various dynamic bonds endow hydrogel with excellent self‐healing ability, adhesiveness, and injectability. This hydrogel also exhibits good antibacterial properties, biocompatibility, and cell migration capabilities. Both in vivo and in vitro experiments demonstrated the outstanding anti‐inflammatory capacity of the hydrogel and its ability to modulate macrophage polarization. Consequently, the hydrogel has proven effective in promoting wound healing in a diabetic full‐thickness wound model through enhanced angiogenesis and collagen deposition. This eco‐friendly plant protein hydrogel offers a sustainable solution for wound care and environmental protection.

The effect of Silver addition and deformation parameters on mechanostructure, biodegradation, antimicrobial and mechanical properties of Zn-based biodegradable alloys.

Although low mechanical properties, Zinc (Zn) alloy systems with Copper (Cu) and Silver (Ag) as alloying elements have strong biocompatibility and biodegradability characteristics. This study examined the effects of rolling parameters and Ag alloying on the mechanical, biodegradable, and final structure of an alloy based on Zn. Comparing treated and untreated specimens, the addition of Ag led to a considerable improvement in both hardness and compressive strength. The produced alloys with varying amounts of Ag (between 1 and 4wt%) were cold rolled at 400-800r/min and friction coefficients between 0.3 and 0.5. The alloys' ultimate strength rose with an increase in rolling speed for Zn1Cu4Ag, and hardness and compressive strengths rose to 80HV and 470MPa, respectively. It was demonstrated that rolling force rose somewhat with Ag concentration but significantly increased with rolling speed and friction. E. Coli and S. aureus were used to assess the biodegradable alloys' antibacterial properties. For the Zn-1Cu-2Ag alloy, the inclusion of Ag resulted in a considerable (50%) rise in antibacterial activity that exceeded the effects seen in other alloy systems.