Silver Interlayer Research Articles

Enhanced Critical Current Density in the Garnet Oxide Electrolyte by a Silver Interlayer.

Ta-doped Li6.4La3Zr1.4Ta0.6O12 (LLZTO) for solid-state lithium batteries demonstrates encouraging performance; however, they encounter issues with lithium dendrite formation that impede their widespread use. Herein, we design a LLZTO ceramic with an interlayer containing a mixed dense layer of Ag and LLZTO, prepared by one-step sintering. The Ag-rich interlayer in LLZTO can hinder the growth and the penetration of lithium dendrites though the reaction between Ag and lithium metal. Compared with the Ag-free counterpart, a higher critical current density of 0.6 mA cm-2, in addition to a longer life span under a current density of 0.2 mA cm-2, is achieved by adopting the interlayer in LLZTO. This research offers novel insights into the engineering of garnet-based solid electrolytes, tailored for the advancement of high-rate lithium metal batteries.

Ag interlayer's influence on microstructure and mechanical properties of laser-welded Ta/304L joints

Tantalum and 304L possess unique properties for aerospace applications. Ta offers high temperature and acid/alkali resistance, while 304L is cost-effective with excellent corrosion resistance. Joining Ta and 304L optimises design, lowers costs and meets specific requirements. This study examined laser lap welding of 0.6 mm Ta and 304L with/without silver interlayer. Joint structure and properties were analysed to reveal the influence of detrimental phases, with first principles calculations for TaFe2 and TaCr2. Without Ag interlayer, the joint had 1857.19 N tensile shear force and 530 HV average weld zone hardness. Adding Ag reduced TaFe2 formation, improving tensile shear strength to 2100.30 N with 460 HV average hardness. First principles calculation confirmed TaCr2's superior phase stability over TaFe2.

Interlayer Engineering and Prelithiation: Empowering Si Anodes for Low-Pressure-Operating All-Solid-State Batteries.

Silicon (Si) anodes, free from the dendritic growth concerns found in lithium (Li) metal anodes, offer a promising alternative for high-energy all-solid-state batteries (ASSBs). However, most advancements in Si anodes have been achieved under impractical high operating pressures, which can mask detrimental electrochemo-mechanical issues. Herein, we effectively address the challenges related to the low-pressure operation of Si anodes in ASSBs by introducing an silver (Ag) interlayer between the solid electrolyte layer (Li6PS5Cl) and anode and prelithiating the anodes. The Si composite electrodes, consisting of Si/polyvinylidene fluoride/carbon nanotubes, are optimized for suitable mechanical properties and electrical connectivity. Although the impact of the Ag interlayer is insignificant at an exceedingly high operating pressure of 70MPa, it substantially enhances the interfacial contacts under a practical low operating pressure of 15MPa. Thus, Ag-coated Si anodes outperform bare Si anodes (discharge capacity: 2430vs 1560mAhg-1). The robust interfacial contact is attributed to the deformable, adhesive properties and protective role of the in situ lithiated Ag interlayer, as evidenced by comprehensive ex situ analyses. Operando electrochemical pressiometry is used effectively to probe the strong interface for Ag-coated Si anodes. Furthermore, prelithiation through the thermal evaporation deposition of Li metal significantly improves the cycling performance.

High-Density Integration of Ultrabright OLEDs on a Miniaturized Needle-Shaped CMOS Backplane.

Direct deposition of organic light-emitting diodes (OLEDs) on silicon-based complementary metal-oxide-semiconductor (CMOS) chips has enabled self-emissive microdisplays with high resolution and fill-factor. Emerging applications of OLEDs in augmented and virtual reality (AR/VR) displays and in biomedical applications, e.g., as brain implants for cell-specific light delivery in optogenetics, require light intensities orders of magnitude above those found in traditional displays. Further requirements often include a microscopic device footprint, a specific shape and ultrastable passivation, e.g., to ensure biocompatibility and minimal invasiveness of OLED-based implants. In this work, up to 1024 ultrabright, microscopic OLEDs are deposited directly on needle-shaped CMOS chips. Transmission electron microscopy and energy-dispersive X-ray spectroscopy are performed on the foundry-provided aluminum contact pads of the CMOS chips to guide a systematic optimization of the contacts. Plasma treatment and implementation of silver interlayers lead to ohmic contact conditions and thus facilitate direct vacuum deposition of orange- and blue-emitting OLED stacks leading to micrometer-sized pixels on the chips. The electronics in each needle allow each pixel to switch individually. The OLED pixels generate a mean optical power density of 0.25mWmm-2, corresponding to >40000cdm-2, well above the requirement for daylight AR applications and optogenetic single-unit activation in the brain.

Microstructural and mechanical characteristics of friction stir welded Al6101/C11000 joints with zinc and silver interlayer

Microstructural and mechanical characteristics of friction stir welded Al6101/C11000 joints with zinc and silver interlayer

Effects of silver interlayer thickness on the microstructure and properties of electron beam welded joints of TC4 titanium and 4J29 Kovar alloys

Abstract Electron beam welding of TC4 titanium alloy and 4J29 Kovar alloy was performed by using different thicknesses of silver interlayers. The microstructure and the composition of welded joints were characterized by scanning electron microscopy, X-ray diffraction, and energy-dipersive spectrometry. The mechanical properties of welded joints were evaluated by tensile strength tests. The results indicated that Ag thickness has great effects on the weld appearance, microstructure, and mechanical properties of electron beam-welded joints. In case of 0.3 and 0.4 mm thickness of Ag interlayers, a considerable part of 4J29 and TC4 melts and a large amount of Fe, Ti, and Ni elements diffuse into the molten pool forming intermetallic compounds (IMCs) such as TiFe2, NiTi, and FeTi. In case of 0.6 mm thickness of Ag interlayer, the welded joint exhibits brazing characteristics with little IMCs near the fusion line of 4J29 Kovar alloy side. When the thickness of the Ag interlayer increases to 0.8 mm, the diffusion of Ti and Fe elements is completely inhibited by Ag. As the thickness of the Ag interlayer increases from 0.3 to 0.8 mm, the tensile strength of the welded sample shows a phenomenon that first rises and then falls, and the largest tensile strength is 243 MPa.

Effect of Interlayer Composition on Microstructure and Properties of Titanium/Aluminum TLP Bond

Abstract The transient liquid phase bonding of titanium and aluminum alloys was investigated, in which the interlayer was a 30-µm-thick brass foil and pure silver foil. The optimized variables used in this work are bonding temperature and time of 600°C and 30 min, respectively. The bonding temperature of 600°C (higher than both Al–Ag and Al–Cu eutectic temperatures) was selected to ensure melting. In both cases, an interesting intergranular eutectic-like phase was observed along the Al2024 grain boundaries. The evaluation of the interfaces of joints via optical microscopy, scanning electron microscopy, line scan, and X-ray diffraction demonstrated that a high temperature in the transient liquid phase process leads to the diffusion of alloying elements to form the molten eutectic. By holding the joint at the bonding temperature, the diffusion of alloying elements resumes, and the liquid interlayer solidifies isothermally because of the changes in the composition of the melted interlayer. The formation of Al2Cu, MgZn2, and TiMg3Zn15 phases was confirmed in the specimen made with brass foil as the interlayer. The interface width is decreased significantly from 8 µm to 2 µm by using silver foil instead of Cu–Zn foil as the interlayer. It is suggested that applying silver interlayer was successful in controlling the diffusion between two base metals and resulted in the formation of Ag2Al and AgMg phases on the fracture surface. This joint gave a higher shear strength of 154.7 MPa. The significant reduction in the strength of the bond due to using Cu–Zn foil as an interlayer (70.2 MPa) can be attributed to aggregation and growth of the brittle intermetallic compounds (IMCs) in the vicinity of the joint interface.

Interfacial reaction and mechanical properties of diffusion bonded titanium/17-4 PH stainless steel dissimilar joint using a silver interlayer

Diffusion bonding of titanium (Ti) to 17-4 PH high strength stainless steel is challenging owing to the formation of brittle Ti-Fe intermetallic compounds (IMCs) at joint interface. In the current study, it was demonstrated that such detrimental Ti-Fe IMCs can be effectively eradicated by using a silver (Ag) interlayer. The diffusion bonded Ti/Ag/17-4 PH stainless steel is characterized by Ti-Ag solid solution, TiAg, remnant Ag interlayer and Ag-(Fe, Cr, Ni) interdiffusion layer. The interfacial reaction phase TiAg exhibited no detrimental effect on bonding strength. During tensile test, ductile fracture took place in the remaining Ag interlayer of resultant joint. Bonding strength up to ∼420 MPa was obtained over bonding durations in the range of 15 ∼ 25 min. It is thus concluded that using an Ag interlayer is highly appealing in improving bonding strength of diffusion bonded Ti/17-4 PH stainless steel dissimilar joint.

Influence of process parameters on the formation and quality of joining zones during induction brazing

Contact materials for electrical switch gears are widely used for connecting and disconnecting electric circuits. These contacts are two component systems, where the contact tips are brazed to the carriers prior to installation. The contacts used in the present work is a 3 layered sandwich structure consisting of a silver-tin oxide (Ag-SnO2) layer, a silver (Ag) inter-layer and a thin layer of the braze. The carrier itself is copper (Cu) - plated steel. The brazing process is accomplished by a high frequency inductive heating process. By varying the brazing parameters, namely, temperature and time, their influence on joint formation is investigated. The brazing joint of the contact tips were characterized by microscopy (light and electron microscopy) and physical analytical techniques (energy dispersive X-ray analysis. The mechanical characteristics were determined with Vickers micro-hardness. Investigations indicated that, comparatively, the variations in temperature had a greater influence on joint zone formation and their mechanical properties. It was further demonstrated that the extended hold times lead to a higher degree of joint zone filling due to a large reduction in pore volume fraction.

Structural optical and electrical properties of a transparent conductive ITO/Al-Ag/ITO multilayer contact.

Indium tin oxide (ITO) is a widely used material for transparent conductive oxide (TCO) films due to its good optical and electrical properties. Improving the optoelectronic properties of ITO films with reduced thickness is crucial and quite challenging. ITO-based multilayer films with an aluminium–silver (Al–Ag) interlayer (ITO/Al–Ag/ITO) and a pure ITO layer (as reference) were prepared by RF and DC sputtering. The microstructural, optical and electrical properties of the ITO/Al–Ag/ITO (IAAI) films were investigated before and after annealing at 400 °C. X-ray diffraction measurements show that the insertion of the Al–Ag intermediate bilayer led to the crystallization of an Ag interlayer even at the as-deposited stage. Peaks attributed to ITO(222), Ag(111) and Al(200) were observed after annealing, indicating an enhancement in crystallinity of the multilayer films. The annealed IAAI film exhibited a remarkable improvement in optical transmittance (86.1%) with a very low sheet resistance of 2.93 Ω/sq. The carrier concentration increased more than twice when the Al–Ag layer was inserted between the ITO layers. The figure of merit of the IAAI multilayer contact has been found to be high at 76.4 × 10−3 Ω−1 compared to a pure ITO contact (69.4 × 10−3 Ω−1). These highly conductive and transparent ITO films with Al–Ag interlayer can be a promising contact for low-resistance optoelectronics devices.

Effect of bonding temperature on interface properties of AZ31 magnesium alloys joined by transient liquid phase using silver interlayer

In this study, AZ31 magnesium alloy was self-joined by employing the transient liquid phase (TLP) technique and using a silver interlayer. Effect of bonding temperature, which ranged from 480 °C to 500 °C temperature, on the joint microstructure and mechanical properties was investigated at a constant 1 h holding time. Microstructural studies showed that at the joining temperature of 480 °C, a large amount of un-diffused silver in the form of intermetallic compounds and a eutectic phase were identified in the joint interface. However, increasing the temperature to 500 °C resulted in an increased diffusion rate of silver atoms into the metallic substrate. Finally, the isothermal solidification phenomenon was evidenced, due to the complete disappearance of the eutectic phase and intermetallic compounds. The uniform chemical composition at the joint interface, was achieved at the 500 °C temperature. Continuous increase in the shear strength of the joints was evidenced in the samples joined, that at higher temperatures reached to a value of 39 MPa for the sample joined at 500 °C temperature. Microstructural analysis of the joint surfaces showed that the samples with the lowest joint strength had the characteristics of a cleavage fracture.

Microstructure and mechanical properties of electron beam welded joints of titanium alloy and Kovar alloy with copper or silver interlayer

The electron beam welding experiments of TC4 titanium alloy and kovar alloy were carried out with Cu or Ag Interlayer. The microstructure and composition of the welded joint were analyzed by optical microscope, scanning electron microscope and x-ray diffraction. The mechanical properties of welded joints were evaluated by microhardness and tensile strength tests. The results show that when Cu is used as the interlayer, there are mainly Cu solid solution and TiFe ,Fe2Ti ,CuTi2 in the joint. The highest hardness of weld is 380HV and the tensile strength is 168 MPa. The joint welded with Ag interlayer exhibit brazing characteristics. The hardness of joint is slightly higher than pure silver, and the tensile strength is 243 MPa.

Large optical nonlinearity of ITO/Ag/ITO sandwiches based on Z-scan measurement.

Indium tin oxide (ITO)-based sandwich structures with the insertion of silver (ITO/Ag/ITO) show large nonlinear optical enhancement of both nonlinear refraction and saturable absorption. Here optical nonlinearity is measured using a Z-scan experiment with a 1310nm pulsed laser at normal incidence. The nonlinear refractive index (n2=15.43×10-16 m2/W) for an ITO/Ag/ITO sandwich with a 14nm silver interlayer and the nonlinear absorption coefficient (β=-648×10-11 m/W) for an ITO/Ag/ITO sandwich with a 10nm silver interlayer are about 18 and 16 times greater than that of a single-layer ITO, respectively. Meanwhile, a large figure of merit and modulation depth values hinted that ITO/Ag/ITO sandwiches are promising saturable absorber materials to switch continuous laser waves into laser pulses. These novel nonlinear optical properties make ITO/Ag/ITO sandwiches a promising candidate for all-optical modulation devices at optical communication wavelengths.

Influence of a Gold Seed in Transparent V2O<italic> <sub>x</sub> </italic>/Ag/V2O<italic> <sub>x</sub> </italic> Selective Contacts for Dopant-Free Silicon Solar Cells

Dielectric/metal/dielectric structures based on vanadium pentoxide with a thin silver interlayer have been optimized to replace traditional transparent electrodes. As would be expected, there is a tradeoff in the metal thickness to achieve high transparency and low sheet resistance simultaneously. It has been demonstrated that an ultra-thin gold seed prevents the tendency of silver to form clusters. This wetting effect reduces the metal thickness needed to form a continuous film, which leads to a higher averaged transmittance and very low sheet resistance. On the other hand, vanadium pentoxide on silicon forms a high-quality hole-selective contact. Thus, these structures can be used as an all-in-one transparent electrode and selective contact for a new kind of heterojunction solar cells. This concept has been proved in a 13.3% efficient solar cell fabricated on n-type silicon wafers. Besides being dopant-free, the complete fabrication route did not require any sputtered transparent electrode.

Facile synthesis of Bi2S3 nanosheet/Zr:Fe2O3 nanorod heterojunction: Effect of Ag interlayer on the change transport and photoelectrochemical stability

In this work, the hydrothermal approach has been used to prepare and control the morphology of Bi2S3 nanosheet (NS)/Zr doped Fe2O3 nanorod (NR) heterojunction grown on fluorine doped tin oxide (FTO) phoptoelectrodes. The effect of morphology of Bi2S3 NS was examined by comparing the photocatalytic activity of Zr:Fe2O3 nanorod with synthesized heterojunctions. This novel heterojunction photoanode exhibits the light harvesting, the photoinduced electron–hole separation and yielding a maximum photocurrent density of ∼1.27mAcm−2 at −0.4V vs. Ag/AgCl under one sun illumination. Bi2S3 NS on surface of the Zr:Fe2O3 NR will act as the active material which shows the dramatic improvement in photocurrent generation. Further, effect of silver interlayer on the interface properties of Bi2S3 NS/Zr:Fe2O3 NR heterojunction was also studied. The results indicated that the silver interlayer reduces charge recombination at interface of Bi2S3 and Zr:Fe2O3. Also, the surface plasmon resonance of Ag and controlled morphology enhances the performance (1.5mAcm−2 at −0.4V) as well as improves the stability of Bi2S3/Zr:Fe2O3 heterojunction photoelectrode. This unique design of the nanoarchitecture provides an attractive pathway for the photogenerated electrons and the silver interlayers has great impact on enhancing charge separation and improving stability of photoanode.

Electric Current-Assisted Joining of Copper Plates Using Silver Formed by In-Situ Decomposition of Ag2C2O4

Pulsed electric current can be used for the fast sintering of powders as well as joining of macroobjects. In this work, we brazed copper plates using a silver layer that was formed in situ by the decomposition of a silver oxalate Ag2C2O4 powder placed between the plates. Joining was conducted in the chamber of a Spark Plasma Sintering (SPS) facility with and without a graphite die. In the die-assisted tooling configuration, indirect heating of the assembly from the graphite die carrying electric current occurred until the brazing layer transformed into metallic silver. The passage of electric current through a Cu/Ag2C2O4/Cu stack placed between the electrodes without a die was possible because of the formation of Cu/Cu contacts in the areas free from the Ag2C2O4 particles. Joints that were formed in the die-assisted experiments showed a slightly higher shear strength (45 MPa) in comparison with joints formed without a die (41 MPa). The shear strength of the reference sample (obtained without a die), a stack of copper plates joined without any brazing layer, was only 31 MPa, which indicates a key role of the silver in producing strong bonding between the plates. This study shows that both die-assisted tooling configurations and those without a die can be used for the SPS brazing of materials by the oxalate-derived silver interlayer.

The Effect of Metal in MoOx/Metal/MoOx Anode on Open Circuit Voltage in Organic Photovoltaic Cells

Archetypal photovoltaic cells are fabricated in order to elucidate the effect of a metal embedded in a semitransparent trilayer electrode on photovoltage. A series of electrodes are formed by thermal deposition of MoOx, metal and MoOx layers, in said succession (MoOx = substoichometric molybdenum trioxide, metal = Au, Cu, Ag, Al, In, Mg, Yb). The parameters of the Schottky‐type cells consisting of thus made bottom anode, a subphthalocyanine boron chloride (SubPc) photoabsorber and a bilayer LiF/Al top cathode are measured and compared to those of the reference cell with an ITO/MoOx anode. Photovoltage does not correlate with the work function of a metal in the anode, while the photocurrent is inversely proportional to the anode sheet resistance. The highest efficiency is achieved with the silver interlayer, but the reference cell with ITO outperforms any cell with a trilayer anode. Then, comparison is made with a series of cells, in which the metal (Cr, Ni, Ag, Al, and Ta) in anode is deposited by a dc magnetron sputtering. In these cells, the photovoltage rises monotonically with the metal work function. Magnetron sputtered nickel in the anode provides the best cell performance, closely approaching that of the reference cell.

A preliminary investigation on microstructure and mechanical properties of dissimilar Al to Cu friction stir welds prepared using silver interlayer

Due to its solid-state nature, friction stir welding (FSW) process can be considered a better alternative for dissimilar welding metals. However, like fusion welding techniques, in friction stir welding growth of thick layers of brittle intermetallics - Cu9Al4 and CuAl2 is a significant issue. One solution to this problem is the use of the suitable interlayer material. Use of interlayer material modifies the joint microstructure with the replacement of thick, brittle intermetallics by more ductile intermetallics in a thin layer or particle form. The present study is a preliminary investigation about joining of AA6082-O to pure copper joints with and without silver (Ag) wire interlayer. Friction stir welded joints were characterized regarding optical microscopy, X-Ray Diffraction (XRD) analysis, microhardness measurement, tensile testing and Scanning Electron Microscopy (SEM) based fractography. The Al-Cu weld prepared using silver interlayer was stronger than without it. The higher strength of the weld with silver interlayer is attributed to the formation of a composite type of structure with intercalation of more ductile Ag2Al intermetallics along with dispersion of Ag particles in stir zone.

AZO/metal/AZO transparent conductive oxide thin films for spray pyrolyzed copper indium sulfide based solar cells

In this study, effects of the aluminum doped zinc oxide (AZO) and metal sandwich structures on the photovoltaic performance of spray pyrolyzed copper indium sulfide (CuInS2) based solar cells have been investigated. Electrical resistivity of the AZO films, 58.5 Ω·cm, has been lowered up to 3.2 × 10−5 Ω·cm via metal interlayer deposition. All sandwich-structured transparent conductive oxide (TCO) layers have been deposited at room temperature and very low radio frequency power. This not only reduced the manufacturing cost but also eliminated the penetration of undesired elements from TCO layer through the absorber. The maximum figure of merit of AZO/molybdenum/AZO, AZO/copper/AZO and AZO/silver/AZO structures were 2.98 × 10−6, 1.06 × 10−3 and 3.91 × 10−2, respectively. This indicated that maximum optical transmittance with minimum sheet resistance has been obtained for the silver interlayer. Then molybdenum/CuInS2/indium sulfide/zinc oxide/AZO-metal-AZO/nickel/aluminum device structure has been manufactured to investigate the photovoltaic parameters. Although all devices had similar open cell voltage, the short circuit current density (Jsc) of the devices has been improved more than 17 times with metal incorporation. The highest Jsc of 10.15 mA/cm2 has been observed for the solar cell having AZO/silver/AZO layer. Alternating current measurements revealed that silver interlayer produced the highest electron transit- and life-time, which resulted the higher Jsc compare to the other metal interlayers. Finally, we improved the photovoltaic parameters of the thin film solar cells with AZO/silver/AZO layer via tailoring the stoichiometry of the CuInS2 absorber layer. The maximum conversion efficiency of 4.19% has been observed for sulfur/(copper + indium) and sulfur/copper ratios of 0.79 and 1.26, respectively. This value is very promising to utilize the AZO/metal/AZO films as TCO layer in low cost and fully ecofriendly thin film solar cells.

Influence of Pin Length and Electrochemical Platings on the Mechanical Strength and Macroscopic Defect Formation in Stationary Shoulder Friction Stir Welding of Aluminium to Copper

The fabrication of dissimilar joints for electrical applications raises challenges for conventional joining technologies. Within solid-state processes, friction stir welding (FSW) provides numerous advantages to realize different joint configurations. However, depending on the intermixing of the materials, defects like hooking and significant intermetallic compound formation around copper fragments are observed and lead to a decrease in joint properties. Therefore, stationary shoulder FSW was applied to produce 2 mm EN AW1050/CW024A lap joints with minimized intermixing at the interface. Compared to conventional FSW, the range of the friction-based heat input can be increased without risking excessive plastification under the tool shoulder. The influence of the pin length on the interfacial structure as well as the mechanical properties were investigated. A pin length of 2.2 mm and hence a plunging of approximately 0.2 mm into the lower copper sheet was found to obtain the highest failure load. A further increase caused the formation of hooking defects, which led to void formation at the interface and failure within the area of the thinned aluminium sheet. The results were also transferred to lap joints with a tin and silver interlayer of 10 µm and also showed good results in terms of bond strength and contact area.