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Cu–Cu soldering is realized under certain pressure and low temperature conditions by using a surface silver film to modify the copper microlayer structure, thus solving the problems of high thermal stress and signal delay aggravation caused by high temperature in the traditional reflow soldering process. The copper microlayer modified with silver film is obtained by electrodeposition. The surface substructure of the Cu microlayer is a nano cone-shaped protrusion. The diameter of the bottom of the cone is 500 nm∼1 μm, and the height of the cone is 1∼2 μm. The thickness of the silver film is about 320 nm, and the modification of the copper layer with silver film can effectively prevent the oxidation of the copper layer. Two silver-modified copper microlayers are placed in face-to-face contact as a soldering couple. A certain pressure and low temperature are applied to the contact area to realize the soldering and interconnection.The morphology of the soldered interface and the average shear strength of the soldered joints are analyzed by scanning electron microscopy, transmission electron microscopy and solder joint tester. It is found that under the optimal soldering parameters of soldering temperature 220 °C, soldering pressure 20 MPa and soldering time 20 min, the nano-conical projections of the Cu micrometer layer are inserted into each other to produce a physical blocking effect. The highly surface-meltable silver film effectively connects the surrounding copper layer as an intermediate buffer layer. The average shear strength of soldering joints is significantly increased. Heat treatment experiments have shown that the average shear strength can be effectively increased by heat treatment for an appropriate period of time. Prolonged exposure to heat has little effect on the average shear strength. With the special morphology of the copper microlayer structure and the nano-size effect of the silver layer, soldering can be done at low temperatures. The quality of the soldering interface is good and small soldering dimensions can be obtained.

Background and Objectives: Membranes in the form of highly ordered nanostructures of porous anodic aluminum oxide (PAAO) with adjustable pore properties were obtained by electrochemical anodizing. PAAO nanostructures were prepared in an oxalic acid electrolyte at a direct current electrochemical potential of 30–60 V. The ready-made nanoporous membranes were modified with thin silver films 1.8, 3.6 and 5.4 nm thick. The study of the membrane surface by scanning electron microscopy has shown that nanoporous membranes have hexagonally arranged and highly ordered arrays of pores with a diameter of (30±4) nm and a packing density of about 1.8 · 10¹⁰ cm–2. Optical interference spectra of PAAO were recorded in the wavelength range of 300–900 nm. The optical properties of nanoporous membranes with a free and silver-modified surface changed depending on the time of interaction of the membrane surface with the ammonia gas flow, which led to changes in the interference pattern and, in turn, to changes in the effective optical thickness (EOT) of the membranes. Features of the influence of the membrane surfacemodified with silver onthe shape and sensitivity ofthe optical signal ofthe sensor have been revealed. The aim ofthis work was to experimentally study the temporal characteristics of the optical spectral response of nanoporous anodic alumina membranes with a free pore surface and modified with thin silver films in an ammonia gas flow. Materials and Methods: The thickness of the PAAO membrane, determined profilometrically, did not exceed 1.0 µm. The average inner diameter of Al2O3 nanopores is (30±4) nm. The silver films were deposited by magnetron sputtering at direct current. Changes in the effective optical thickness are used to quantify changes in the optical properties of the membrane. Changes in the effective optical thickness will be mainly determined by the effective refractive index of the PAAO-Ag molecular film of the adsorbed gas structure. The effective refractive index of the membrane was determined from the measured position of the interference maxima and the given membrane thickness. Results: Association processes have been considered, i.e. binding of analyte molecules to the surface of the PAAO nanoporous membrane. A stream of gaseous ammonia was chosen as the analyte. According to the Langmuir isotherm model, the sensor response during real-time measurements should follow a negative exponential trend. It has been shown that the shape of the sensor’s optical signal qualitatively repeats the shape of the theoretical curve of real-time optical probing in the regions of molecular binding and equilibrium. The molecular association time of the free surface of the PAAO nanoporous membrane was 7 ± 1 minutes. The deposition of thin silver films on the surface of a nanoporous PAAO membrane leads to a change in the shape of the optical signal and a decrease in its magnitude. Conclusion: On the basis of the synthesized nanoporous PAAO membranes with a free surface and modified with ultrathin silver films, experimental studies of the effect of ammonia flow on multibeam light interference in such membranes have been carried out. It has been found that the surface roughness and size effect of the silver film thickness have a significant effect on the transmission spectra and sensory sensitivity of the membranes. It has been shown that the largest relative change in the refractive index of the membrane in an ammonia flow is observed for the thinnest silver film 1.8 nm thick. It has been noted that there is a threshold value of the thickness of a silver film deposited on the surface of a nanoporous PAAО membrane, above which the use of such films in optical sensors with the mechanism of multipath light interference is not advisable, and the use of a different mechanism is required, for example, the mechanism of localized surface plasmon resonance.

Spectral optical properties of synthesized ceramic nanoporous membranes based on anodic aluminum oxide coated silver in saturated ammonia gas flow have been experimentally investigated. Based on the measured transmission spectra and detected interference part of the spectra in wavelength range from 550 to 900 nm, temporal and spectral dependencies of the effective optical thickness and its changes in non-equilibrium conditions were obtained due to adsorption of ammonia molecules on silver film surface. According to detected and measured interference maximum shifts up to 14 nm in transmission spectra of Al2O3 + Ag membranes in ammonia gas flow, the possibility of constructing a selective interferometric optical sensors with 10–15 min response time is shown. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) reduction at a plasmonically active silver cathode was investigated by varying the pressure and temperature at multiple applied potentials under both dark and illuminated conditions to understand the mechanism of selectivity changes driven by plasmon-enhanced electrochemical conversion. CO2 partial pressures (PCO2) from 0.2 to 1 atm were studied during linear sweep voltammetry and chronoamperometry at −0.7, −0.9, and −1.1 VRHE. At a given applied overpotential the total current density increased with increasing PCO2 in both the dark and the light, but there were significant differences in the Tafel behavior between dark and illuminated conditions. The reduction of CO2 to carbon monoxide (CO) was found to have first-order behavior with respect to PCO2 at all applied potentials in both the dark and the light, likely indicating no change in the rate-determining step upon illumination. Activity for the hydrogen (H2) evolution reaction decreased with increasing PCO2 at slightly different rates in the dark and the light at each applied potential, making it unclear if light is influencing CO or H2 intermediate adsorbate coverage. Both formate and methanol production showed no dependence on PCO2 under any conditions, but the true reaction orders may be masked by the much higher activity for CO and H2 at the silver cathode. The investigation of product distribution with temperature at 14, 22, and 32∘C at −0.7, −0.9, and −1.1 VRHE in both the dark and the light demonstrated that the selectivity changes observed upon illumination are not caused by local heating of the cathode surface.

Carbon dioxide (CO2) reduction at a plasmonically active silver cathode was investigated by varying the pressure and temperature at multiple applied potentials under both dark and illuminated conditions to understand the mechanism of selectivity changes driven by plasmon-enhanced electrochemical conversion. CO2 partial pressures (PCO2) from 0.2 to 1 atm were studied during linear sweep voltammetry and chronoamperometry at −0.7, −0.9, and −1.1 VRHE. At a given applied overpotential the total current density increased with increasing PCO2 in both the dark and the light, but there were significant differences in the Tafel behavior between dark and illuminated conditions. The reduction of CO2 to carbon monoxide (CO) was found to have first-order behavior with respect to PCO2 at all applied potentials in both the dark and the light, likely indicating no change in the rate-determining step upon illumination. Activity for the hydrogen (H2) evolution reaction decreased with increasing PCO2 at slightly different rates in the dark and the light at each applied potential, making it unclear if light is influencing CO or H2 intermediate adsorbate coverage. Both formate and methanol production showed no dependence on PCO2 under any conditions, but the true reaction orders may be masked by the much higher activity for CO and H2 at the silver cathode. The investigation of product distribution with temperature at 14, 22, and 32∘C at −0.7, −0.9, and −1.1 VRHE in both the dark and the light demonstrated that the selectivity changes observed upon illumination are not caused by local heating of the cathode surface.

In this work, we have proposed and tested a new version of an optoelectronic sensor for detecting gas molecules based on the effect of spectral surface plasmon resonance (SPR) in the chromatic mode with colorimetric registration of the R, G, B color components of reflected light. A thin 40-nm silver film on the base face of the prism with SPR excitation in the Kretschmann geometry is used as an optical sensitive element that allows us to realize a full-fledged SPR effect in the entire visible range of the spectrum from 450 to 700 nm. The physical nature of the sensory effect is a change in the refractive index of the sensitive coating on the silver film, which directly affects the SPR parameters. The films of polyvinyl formal ethylal were used as a coating selective to the number of organic analytes. A laboratory version of the portable device for implementation of a gas sensor based on the SPR-RGB effect was created. Performance of the proposed sensory method and the corresponding device were assessed using different types of alcohols as volatile organic analytes. [ABSTRACT FROM AUTHOR]

In this paper, the silver-coated large-core suspended-core fiber (LSCF) probe was fabricated by the dynamic chemical liquid phase deposition method for surface-enhanced Raman scattering (SERS) sensing. The 4-mercaptophenylboronic acid (4-MPBA) monolayer was assembled in the LSCF as the recognition monolayer. Taking advantage of the appropriate core size of the LSCF, a custom-made Y-type optical fiber patch cable was utilized to connect the semiconductor laser, Raman spectrometer, and the proposed fiber SERS probe. The SERS signal is propagated in the silver-coated air channels, which can effectively reduce the Raman and fluorescence background of the silica core. Experiments were performed to measure the Raman scattering spectra of the 4-MPBA in the silver-coated LSCF in a non-enhanced and enhanced case. The experiment results showed that the Raman signal strength was enhanced more than 6 times by the surface plasmon resonance compared with the non-enhanced case. The proposed LSCF for SERS sensing technology provides huge research value for the fiber SERS probes in biomedicine and environmental science. The combination of SERS and microstructured optical fibers offers a potential approach for SERS detection

This study introduced an optical fiber core sensor designed to measure chloride ions by removing the fiber's coating and cladding, allowing direct interaction between the fiber core and external solutions, thereby enhancing measurement sensitivity. Two types of fibers, plastic and quartz, were evaluated for their efficacy as sensors. Experimental results demonstrated that the fabricated plastic core fiber failed to accurately reflect alterations in external solutions onto the spectrum, making it unsuitable for sensor applications. Conversely, the quartz fiber core, when treated with chloroform to dissolve its cladding, exhibited superior performance due to its wider transmission wavelength range and higher durability. The integration of a silver film on the core further improved the sensor's sensitivity through surface plasmon resonance. The study also explored the impact of thin-film and thick-film formations on sensor performance, with the thin film providing rapid response times and the thick film offering enhanced durability. This advancement holds significant potential for applications in environmental monitoring and the early detection of chloride-induced corrosion in various structural materials. • Optical fiber core sensor for chloride ion measurement by exposing the core to interact directly with external solutions. • Chloroform-treated quartz fiber core improved sensor performance. • A highly sensitive chloride ion sensor was developed by depositing a thin silver film onto the quartz fiber core. • The sensor detected chloride ions via spectrum changes from AgCl formation on the silver-coated core. • Thinner silver films were more responsive to chloride ions. [ABSTRACT FROM AUTHOR]

Optimizing the performance of front silver paste is of great significance in improving the efficiency of the photoelectric conversion of crystalline silicon solar cells. As a conductive functional phase of silver paste, the structure and performance of silver powder have an important influence on the sintering process of silver paste and the conductivity of silver electrodes. Because of their two−dimensional structure, flake silver powders can effectively increase the contact area with other silver powders and silicon cells before sintering. Additionally, flake silver particles have higher surface energy and sintering activity than spherical silver particles of the same particle size. However, recent research has mainly focused on the influence of the particle size of silver powder. This paper fills the research gap regarding the morphology of silver powders and clarifies the influence of flake silver powders on the performance of silver paste. The influence of the ratio of spherical silver powder to flake silver powder in silver paste on the sheet resistance, adhesion, and specific contact resistivity of silver film after sintering at 800 °C was studied, and the optimal ratio was determined according to a cross−sectional contact picture of the silver film. The results showed that with the increase in the mass fraction of the flake silver powder, the sheet resistance of the sintered silver film gradually increased, the adhesion first increased and then decreased, and the specific contact resistance first decreased and then increased. When the flake silver powder content was 0%, the minimum sheet resistance of the silver film was 2.41 m Ω/☐. When the flake silver powder content was 30%, the maximum adhesion of the silver film was 6.07 N. When the flake silver powder content was 50%, the minimum specific contact resistivity of the silver film was 0.25 Ω·cm2. In conclusion, when the flake silver powder content was 30%, the comprehensive performance of the silver film was the best. [ABSTRACT FROM AUTHOR]

In this paper, we present a wound-dressing-based antenna fabricated via screen-printed and inkjet-printed technologies. To inkjet print a conductive film on wound dressing, it must be screen-printed, UV-curable-pasted, and hard-baked to provide appropriate surface wettability. Two passes were UV-curable-pasted and hard-baked at 100 °C for 2 h on the wound dressing to obtain 65° WCA for silver printing. The silver film was printed onto the wound dressing at room-tempature with 23 μm droplet spacing for three passes, then sintered at 120 °C for 1 h. By optimizing the inkjet printing conditions by modifying the surface morphologies and electrical properties, three-pass printed silver films with 3.15 μm thickness and 1.05 × 107 S/m conductivity were obtained. The insertion losses at the resonant frequency (17 and 8.85 GHz) were −2.9 and −2.1 dB for the 5000 and 10,000 μm microstrip transmission lines, respectively. The material properties of wound dressing with the relative permittivity and loss-tangent of 3.15–3.25 and 0.04–0.05, respectively, were determined by two transmission line methods and used for antenna design. A quasi-Yagi antenna was designed and implemented on the wound-dressing with an antenna bandwidth of 3.2–4.6 GHz, maximal gain of 0.67 dBi, and 42% radiation efficiency. The bending effects parallel and perpendicular to the dipole direction of three fixtures were also examined. The gain decreased from 0.67 to −1.22 dBi and −0.44 dBi for a flat to curvature radius of 5 cm fixture after parallel and perpendicular bending, respectively. Although the maximal gain was reduced with the bending radius, the directivity of the radiation pattern remained unchanged. The feasibility of a wound-dressing antenna demonstrates that inkjet-printed technology enables fast fabrication with low cost and environmental friendliness. Additionally, inkjet-printed technology can be combined with sensing technology to realize remote medical monitoring, such as with smart bandages, for assessment of chronic wound status or basic physical conditions. [ABSTRACT FROM AUTHOR]

A surface plasmon resonance imaging (SPRI)-based biosensor is demonstrated for the detection of both hydrogen peroxide (H 2 O 2) and glucose. The H 2 O 2 to be detected acts as an oxidant and etch the silver film. This process gradually effects on resonance condition and consequently the reflected light intensity at a fixed angle. The etching rate of the silver film shows a clear relation with the H 2 O 2 concentration. Therefore, monitoring the reflected light intensity progressively changing over a few minutes, enables accurate detection of H 2 O 2 concentrations ranging from 0 to 200 μM (within physiological range of 0.25–50 μM), with a remarkable limit of detection (LOD) as low as 40 nM. In this regard, the behavior of the surface plasmon resonance (SPR) dip in response to the reduction of the silver film thickness is predicted by Winspall simulation software. These simulation results are in good agreement with the experimental results. Moreover, the proposed method can be applied to determine glucose concentrations ranging from 0 to 10 mM, encompassing the physiological range of 3–8 mM. This is achieved by observing the generated H 2 O 2 through the enzymatic oxidation reaction between glucose and glucose oxidase (Gox). The sensor demonstrates remarkable sensitivity and selectivity, with a detection limit as low as 175 μM for glucose concentration. Furthermore, accurate measurement of glucose concentration in an actual human serum sample is achievable with the proposed sensor, using the standard addition method. The suggested glucose sensor shows promising prospects for use in routine glucose testing, employing a label-free, real-time, and multiplex detection approach.© 2017 Elsevier Inc. All rights reserved. [Display omitted] • Dual Detection : SPRI biosensor detects both H2O2 and glucose. • H2O2 Sensing : Silver film etching by H2O2 alters light intensity, enabling detection down to 40 nM. • Simulation Validation : Winspall software confirms SPR dip behavior, aligning with experimental data. • Glucose Detection : Enzymatic oxidation detects glucose concentrations from 0 to 10 mM with a 175 μM detection limit. • Real-world Application : Biosensor accurately measures glucose in human serum, promising routine testing with label-free, real-time detection. [ABSTRACT FROM AUTHOR]

Optimizing the performance of front silver paste is of great significance in improving the efficiency of the photoelectric conversion of crystalline silicon solar cells. As a conductive functional phase of silver paste, the structure and performance of silver powder have an important influence on the sintering process of silver paste and the conductivity of silver electrodes. Because of their two−dimensional structure, flake silver powders can effectively increase the contact area with other silver powders and silicon cells before sintering. Additionally, flake silver particles have higher surface energy and sintering activity than spherical silver particles of the same particle size. However, recent research has mainly focused on the influence of the particle size of silver powder. This paper fills the research gap regarding the morphology of silver powders and clarifies the influence of flake silver powders on the performance of silver paste. The influence of the ratio of spherical silver powder to flake silver powder in silver paste on the sheet resistance, adhesion, and specific contact resistivity of silver film after sintering at 800 °C was studied, and the optimal ratio was determined according to a cross−sectional contact picture of the silver film. The results showed that with the increase in the mass fraction of the flake silver powder, the sheet resistance of the sintered silver film gradually increased, the adhesion first increased and then decreased, and the specific contact resistance first decreased and then increased. When the flake silver powder content was 0%, the minimum sheet resistance of the silver film was 2.41 m Ω/☐. When the flake silver powder content was 30%, the maximum adhesion of the silver film was 6.07 N. When the flake silver powder content was 50%, the minimum specific contact resistivity of the silver film was 0.25 Ω·cm2. In conclusion, when the flake silver powder content was 30%, the comprehensive performance of the silver film was the best.

In this paper, we present a wound-dressing-based antenna fabricated via screen-printed and inkjet-printed technologies. To inkjet print a conductive film on wound dressing, it must be screen-printed, UV-curable-pasted, and hard-baked to provide appropriate surface wettability. Two passes were UV-curable-pasted and hard-baked at 100 °C for 2 h on the wound dressing to obtain 65° WCA for silver printing. The silver film was printed onto the wound dressing at room-tempature with 23 μm droplet spacing for three passes, then sintered at 120 °C for 1 h. By optimizing the inkjet printing conditions by modifying the surface morphologies and electrical properties, three-pass printed silver films with 3.15 μm thickness and 1.05 × 107 S/m conductivity were obtained. The insertion losses at the resonant frequency (17 and 8.85 GHz) were −2.9 and −2.1 dB for the 5000 and 10,000 μm microstrip transmission lines, respectively. The material properties of wound dressing with the relative permittivity and loss-tangent of 3.15–3.25 and 0.04–0.05, respectively, were determined by two transmission line methods and used for antenna design. A quasi-Yagi antenna was designed and implemented on the wound-dressing with an antenna bandwidth of 3.2–4.6 GHz, maximal gain of 0.67 dBi, and 42% radiation efficiency. The bending effects parallel and perpendicular to the dipole direction of three fixtures were also examined. The gain decreased from 0.67 to −1.22 dBi and −0.44 dBi for a flat to curvature radius of 5 cm fixture after parallel and perpendicular bending, respectively. Although the maximal gain was reduced with the bending radius, the directivity of the radiation pattern remained unchanged. The feasibility of a wound-dressing antenna demonstrates that inkjet-printed technology enables fast fabrication with low cost and environmental friendliness. Additionally, inkjet-printed technology can be combined with sensing technology to realize remote medical monitoring, such as with smart bandages, for assessment of chronic wound status or basic physical conditions.

Cu-Cu soldering is realized under certain pressure and low temperature conditions by using a surface silver film to modify the copper microlayer structure, thus solving the problems of high thermal stress and signal delay aggravation caused by high temperature in the traditional reflow soldering process. The copper microlayer modified with silver film is obtained by electrodeposition. The surface substructure of the Cu microlayer is a nano cone-shaped protrusion. The diameter of the bottom of the cone is 500 nm∼1 μm, and the height of the cone is 1∼2 μm. The thickness of the silver film is about 320 nm, and the modification of the copper layer with silver film can effectively prevent the oxidation of the copper layer. Two silver-modified copper microlayers are placed in face-to-face contact as a soldering couple. A certain pressure and low temperature are applied to the contact area to realize the soldering and interconnection. The morphology of the soldered interface and the average shear strength of the soldered joints are analyzed by scanning electron microscopy, transmission electron microscopy and solder joint tester. It is found that under the optimal soldering parameters of soldering temperature 220 °C, soldering pressure 20 MPa and soldering time 20 min, the nano-conical projections of the Cu micrometer layer are inserted into each other to produce a physical blocking effect. The highly surface-meltable silver film effectively connects the surrounding copper layer as an intermediate buffer layer. The average shear strength of soldering joints is significantly increased. Heat treatment experiments have shown that the average shear strength can be effectively increased by heat treatment for an appropriate period of time. Prolonged exposure to heat has little effect on the average shear strength. With the special morphology of the copper microlayer structure and the nano-size effect of the silver layer, soldering can be done at low temperatures. The quality of the soldering interface is good and small soldering dimensions can be obtained., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Published by Elsevier Ltd.)

Ultrathin silver films with low loss in the visible and near-infrared spectrum range have been widely used in the fields of metamaterials and optoelectronics. In this study, Al-doped silver films were prepared by the magnetron sputtering method and were characterized by surface morphology, electrical conductivity, and light transmittance analyses. Molecular dynamics simulations and first-principles density functional theory calculations were applied to study the surface morphologies and migration pathway for the formation mechanisms in Al-doped silver films. The results indicate that the migration barrier of silver on a pristine silver surface is commonly lower than that of an Al-doped surface, revealing that the aluminum atoms in the doping site decrease the surface mobility and are conducive to the formation of small islands of silver. When the islands are dense, they coalesce into a single layer, leading to a smoother surface. This might be the reason for the observably lower 3D growth mode of silver on an Al-doped silver surface. Our results with electronic structure insights on the mechanism of the Al dopants on surface morphologies might benefit the quality control of the silver thin films.

Plasmonic photo-thermoelectric conversion offers an alternative photodetection mechanism that is not restricted by semiconductor bandgaps. Here, we report a plasmonic photodetector consisting of an ultra-thin silver film with nanohole array, whose photodetection mechanism is based on thermoelectric conversion triggered by plasmonic local heating. The detector exhibits a maximum photocurrent at the wavelength of the surface plasmon polaritons, determined by the periodicity of the nanoholes. Hence, the response wavelength of the detector can be controlled via the morphological parameters of the nanohole pattern. The contribution of plasmonic local heating to thermoelectric conversion is verified experimentally and numerically, enabling discussion on the mechanisms governing light detection. These results provide a starting point for the development of other nanoscale photodetectors. [ABSTRACT FROM AUTHOR]

In this work, a detailed study is conducted on the visible transmittance, solar reflectance, and emissivity properties of low-emissivity coatings composed of one, two, and three layers of silver. The results demonstrate significant enhancements in both optical and thermal properties achievable by increasing the number of silver layers, leading to coatings that are more transparent in the visible spectrum, more reflective in the near-infrared, with lower emissivity and lower sheet resistance. The aesthetic adjustment possibilities of the different structures are also examined, with coatings composed of three layers of silver being more flexible. [Display omitted] • Comparison of low-e coatings composed of one, two, and three layers of silver. • Manufacturing of low-e coatings through sputtering in a semi-industrial facility. • Transparent and conductive coatings based on thin layers of silver. [ABSTRACT FROM AUTHOR]

In this paper, the silver-coated large-core suspended-core fiber (LSCF) probe was fabricated by the dynamic chemical liquid phase deposition method for surface-enhanced Raman scattering (SERS) sensing. The 4-mercaptophenylboronic acid (4-MPBA) monolayer was assembled in the LSCF as the recognition monolayer. Taking advantage of the appropriate core size of the LSCF, a custom-made Y-type optical fiber patch cable was utilized to connect the semiconductor laser, Raman spectrometer, and the proposed fiber SERS probe. The SERS signal is propagated in the silver-coated air channels, which can effectively reduce the Raman and fluorescence background of the silica core. Experiments were performed to measure the Raman scattering spectra of the 4-MPBA in the silver-coated LSCF in a non-enhanced and enhanced case . The experiment results showed that the Raman signal strength was enhanced more than 6 times by the surface plasmon resonance compared with the non-enhanced case. The proposed LSCF for SERS sensing technology provides huge research value for the fiber SERS probes in biomedicine and environmental science. The combination of SERS and microstructured optical fibers offers a potential approach for SERS detection.

Ag metal films are deposited by the magnetron sputtering technique. The electron nonequilibrium relaxation process is studied, the time and the number of the electron nonequilibrium relaxation in the Ag films is measured using the femtosecond transient thermal reflection technique. It plays a positive role in solving the problems of the devices which are damaged in the process of the laser heating the metals. The results show that under the multiple pulses heating, the transient reflectivity curves (ΔR/R curves) emerge several sharply rising peaks, and the times of the excitation and the duration of the electron equilibrium relaxation depend of both the thickness and the femtosecond laser pump pulse power. [ABSTRACT FROM AUTHOR]

Indium gallium zinc oxide/silver/indium gallium zinc oxide (IGZO/Ag/IGZO) triple-layer films were deposited on glass substrates using radio frequency (R.F.) magnetron sputtering. We had found that the deposition time (thickness) of Ag had a large effect on the electrical (conductive) and transmittance characteristics of the IGZO/Ag/IGZO triple-layer films. As the SIMS depth profile analysis was conducted on the IGZO/Ag/IGZO triple-layer films, as expected, the thickness of the Ag layer increased with the increase of deposition time. In the visible wavelength region, as the deposition time of Ag layer increased from 10 s to 30 s, the all IGZO/Ag/IGZO triple-layer films revealed the amorphous phase. As the deposition time of Ag layer increased, the maximum transmittance ratio slightly decreased and the wavelength to reveal the maximum transmittance ratio was shifted to lower value. Also, the mobility and carrier concentration increased and the resistivity decreased with increasing deposition times of Ag layer. The triple-layer IGZO/Ag/IGZO films showed impressive transmittance and electrical conductivity and the IGZO/Ag/IGZO triple-layer films with the 25 s Ag deposition time possessed satisfactory optical and electrical properties for potential applications. • The triple-layer films were deposited using RF magnetron sputtering. • The triple-layer films showed impressive transmittance and electrical conductivity with the 20 s Ag deposition time. • The sheet resistance and average optical transmittance were 4.5 Ω/□ and 82.8%, respectively. [ABSTRACT FROM AUTHOR]

Single nanowire becomes attractive as a basic component of various nanodevices. Nanowire joining is one of the crucial operations in micro-nano manufacturing. Compared with other joining methods, such as electrical current heating and mechanical pressure, laser illumination can yield metallic contacts through local precision nanosoldering. In this paper, the authors report the joining of one single copper nanowire (CuNW) to a silver film by a laser illumination method. They first cut the silver film on a flexible substrate to form a gap of about 1–4 μm by a 1030 nm femtosecond (fs) pulsed laser. Then, they coat CuNWs by dripping nanowire solution onto the gap, bridge the gap, and then join single CuNW with the fs pulsed laser. By comparison with scanning electron microscope images after and before laser illumination, it is found that the local silver film melts, then wraps partial CuNW, and finally crystallizes. So, the joining is through a part of CuNW embedded in a silver film. In addition, the authors further analyze the joining situation by directly measuring the resistance variation between after joining (Ra) and before joining (Rb). It is demonstrated that the resistance ratio of Ra to Rb decreases from 0.835 to 0.172 with increasing laser power from 10 to 40 mW for 3 s of the laser illumination time. The resistance ratio of Ra to Rb decreases from 0.936 to 0.368 with an increment of the laser illumination time from 1 to 4 s at a laser power of 30 mW. Finally, the authors find that the welded single CuNW enables sensing of glucose at a concentration of 10−5M. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) sensors are extensively used with refractive index and temperature sensing. A novel SPR sensor for temperature measurement is proposed in this paper. A novel two-dimensional material Tungsten disulfide is used to improve the sensitivity of this temperature sensor. Polydimethylsiloxane covers the sensing area to better sense changes in external temperature. The experimental results show that the SPR sensor can measure the temperature range of 30 °C − 100 °C with a temperature sensitivity of 2.03 nm/°C. This sensor has the merits of a simple structure, low manufacturing process cost, a broad range of detection, and high sensitivity compared to other temperature sensors. Therefore, the sensor has great potential for future applications in environmental monitoring, biomedicine, the food industry, and other production activities. • Ultra-high sensor performance using only a simple structure. • Combining PCF and SPR effects to achieve high sensitivity sensor devices. • Application of the new two-dimensional material WS2 to the outer layer of metal films for stronger excitation of SPR effects. • Temperature sensing using PDMS, a new temperature-sensitive material that senses changes in external temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • A way to obtain conductive silver films is proposed. • Conductive silver films were formed by the Doctor Blade method. • Janus membrane based on conductive silver film was obtained. • Obtained membrane is a promising material for flexible microelectronics. The organasol of nanoparticles (3 M, the particle size 6 ± 1 nm) was synthesized by the silver nitrate reduction with hydrazine in the reverse emulsions stabilized by the sodium bis(2-ethylhexyl)sulfosuccinate. The obtained silver nanoparticle emulsion was concentrated using electrophoretic concentration. The silver nanoparticle films with tunable thickness (from 3.9 ± 0.2 to 1.7 ± 0.2 µm), porosity (from 26 ± 10 to 46 ± 12%), density (from 5.7 ± 1.5 to 7.8 ± 3.0 g/cm3), roughness (from 4 ± 2 to 131 ± 19 nm) and surface electrical resistivity (from 0.03 ± 0.01 to 0.10 ± 0.01 Ohm/□) were obtained. The sintering process of the silver nanoparticle films was studied by in situ XRD experiment using synchrotron radiation. The separation procedure for the metallic films from the solid substrates was proposed. The separated sintered silver nanoparticle film was considered as a Janus membrane. The wetting asymmetry of the obtained Janus membrane was of 39°. The obtained films were considered as promising functional material with the bactericidal and the electrical conductive properties. The obtained Janus membrane could be placed on the flexible polymer substrates. [ABSTRACT FROM AUTHOR]

Plasmonic photo-thermoelectric conversion offers an alternative photodetection mechanism that is not restricted by semiconductor bandgaps. Here, we report a plasmonic photodetector consisting of an ultra-thin silver film with nanohole array, whose photodetection mechanism is based on thermoelectric conversion triggered by plasmonic local heating. The detector exhibits a maximum photocurrent at the wavelength of the surface plasmon polaritons, determined by the periodicity of the nanoholes. Hence, the response wavelength of the detector can be controlled via the morphological parameters of the nanohole pattern. The contribution of plasmonic local heating to thermoelectric conversion is verified experimentally and numerically, enabling discussion on the mechanisms governing light detection. These results provide a starting point for the development of other nanoscale photodetectors.

Due to the increase in working temperature of power electronic components, the conventional component design is slowly facing out and is being replaced with new design which introduces new challenges to the manufacturing process. Flat silver films with customised geometry are required to realise the new component design but such films are hard to produce with conventional manufacturing methods. This paper details the feasibility study of using laser ablation technique in producing customised patterns on thin silver film for lamination during power electronic manufacturing process. The laser used in the study is a 30 W nanosecond laser from IPG with a wavelength of 1064 nm. The ablation profiles with different laser parameters are presented and the influence of the beam energy distribution and pulse duration on the ablation quality is discussed. It was found that shorter pulse duration produces better surface finish with minimal re-melting and smaller cut width. The optimum laser parameter was determined to be 30 W with a pulse duration of 4 ns, frequency of 750 kHz and a scanning speed of 1000 mm/s to ablate a silver film of ~70 μm thick on a PET substrate. The optimised laser ablation parameters were employed to demonstrate the production of a customised silver film. [ABSTRACT FROM AUTHOR]

In this paper, we present a stable silver-based surface plasmon resonance (SPR) sensor using a self-assembled monolayer (SAM) as a protection layer and investigated its efficiency in water and 0.01 M phosphate buffered saline (PBS). By simulation, silver-based SPR sensor has a better performance in field enhancement and penetration depth than that of a gold-based SPR sensor, which are 5 and 1.4 times, respectively. To overcome the instability of the bare silver film and investigate the efficiency of the protected layer, the SAM of 11-mercapto-1-undecanol (MUD) was used as a protection layer. Stability experiment results show that the protected silver film exhibited excellent stability either in pure water or 0.01 M PBS buffer. The sensitivity of the silver-based SPR sensor was calculated to be 127.26 deg/RIU (refractive index unit), measured with different concentrations of NaCl solutions. Further, a very high refractive resolution for the silver-based SPR sensor was found to be 2.207 × 10-7 RIU, which reaches the theoretical limit in the wavelength of 632.8 nm for a SPR sensor reported in the literature. Using a mixed SAM of 16-mercaptohexadecanoic acid (MHDA) and a MUD layer with a ratio of 1:10, this immunosensor for the rabbit immunoglobulin G (IgG) molecule with a limit of detection as low as 22.516 ng/mL was achieved. [ABSTRACT FROM AUTHOR]

Experimental research results of silicate glass surface layers modification by the influence of electron beams with 5-50 keV energies and 20-50 mC/cm2 doses are presented. It is shown that during the glasses exposure to an electron beam with 20-50 keV electron energies, a gradient optical waveguide with increased refractive index on waveguide axis Δn = 0.01-0.04 is formed in the surface layer. Сhemical etching rate is increased in the exposed area by up to two times which is related to glass grid destruction. Depending on irradiation dose thin film or silver nanoparticles with the size less than 20nm are formed on the surface of the silver containing glasses for electron energies less than 10 keV. Silver films drawn on the surface of the glass are dissolved into the glass bulk for electron energies 20-50 keV and 20-50 mC/cm2 dose. Basic mechanisms causing these effects are: chemical bonds breaking of spatial glass grid by high energy electrons, formation of negative volume charge inside the glass and field migration of positive metal ions into the volume charge region. Achieved results can be used in photonics, integral optics and nanoplasmonics device fabrication.

We have investigated, in a numerical and experimental way, a refractive index (RI) sensor based on surface plasmon resonance (SPR) in a silver-coated light-diffusing fiber (LDF). The experimental tests were conducted using water-glycerine mixtures with refractive indices ranging from 1.332 to 1.388. In the considered refractive index range, the experimental results show a sensitivity of the SPR wavelength to the outer medium’s RI ranging from ~2600 to ~4700 nm/RIU, which is larger than the sensitivity recently reported for a gold-coated LDF sensor (~1200 to ~4000 nm/RIU). The silver-coated sensor is also shown to ensure a higher signal-to-noise ratio (SNR) compared to the gold-coated sensor.

The specific features of fabrication of 3D silicon structures via local formation of a sacrificial porous silicon layer by metal-assisted chemical etching with 50- and 100-nm-thick silver films as a catalyst are studied. It is found that the mass transfer of Ag ions, caused by the temperature gradient, affects the surface morphology of the structure being formed, depending on the linear size of the mask-catalyst. [ABSTRACT FROM AUTHOR]