Silver Tracks Research Articles

Argon plasma sintering of inkjet printed silver tracks on polymer substrates

An alternative and selective sintering method for the fabrication of conductive silver tracks on common polymer substrates is presented, by exposure to low-pressure argon plasma. Inkjet printing has been used to pattern a silver nanoparticle ink. This resulted in conductive features with a resistivity less than one order of magnitude higher than the bulk value of silver without affecting the polymer substrate. This process may be employed in the production of conductive features with low material usage on common polymer substrates in, for example, printed electronics.

Low Curing Temperature Silver Tracks from Soluble Inks

AbstractSilver neodecanoate is sensitive to both ultra violet light (UV) and heat, and is a good inkjet printing precursor when dissolved in xylene. We have studied the electrical properties of inkjet printed silver samples, derived from silver neodecanoate ink, and investigated the influence of UV treatment before thermal curing the silver samples. In addition we have studied the influence of thermal pre-treatment on the printed samples. Thermally cured printed tracks and pads show minimum resistivity of approximately 3 x bulk silver. Their microstructure shows that the silver salt has converted to an interconnected network of silver nanoparticles after curing. The resistance of the printed tracks are shown to relate to the connectivity of the resulting sintered nanoparticle network as measured by the ratio of the sintered neck diameter to the original particle diameter.

“Invisible” Silver Tracks Produced by Combining Hot‐Embossing and Inkjet Printing

AbstractHot‐embossed features are prepared by pushing customized and standard silicon calibration gratings, known as masters, into either polystyrene or polycarbonate, which are kept above their glass transition temperatures. droplet of a silver nanoparticle ink is then dispensed over one of these as‐formed grooves using an inkjet printer. The ink fills the grooves as a consequence of capillary forces and is observed to form tracks with a uniform width. The tracks are described as ‘invisible’ on account of having widths ranging from 5 to 15 µm. Wider tracks can be produced by dispensing more droplets and tracks with different morphologies can be produced by using different masters. Several as‐prepared features are thermally treated to produce conductive silver tracks. The conductivity of the tracks is found to be ∼20% that of bulk silver.

Inkjet Printing of conductive silver tracks in high resolution and the (alternative) sintering thereof

We present different methods to improve the resolution of inkjet printed lines. The first is a direct method without surface treatment. Small droplets of a single picoliter have been inkjet printed directly onto a polymeric foil that has a surface energy smaller than that of common polymer foils. On the other hand the surface energy was high enough to form continuous tracks, which is usually the case when printing, for example, onto Teflon foil. The second method uses a combination of inkjet printing and hot-embossing. The latter technique is used to create microchannels in a polymer foil by pressing a master into the substrate, which is held above its glass transition temperature, after which an inkjet printer is used to dispense single droplets of a silver nanoparticulate ink over these as-formed channels. Subsequently, the channels will fill by means of capillary forces and afterwards sintering resulted not only in narrow tracks smaller than 10 μm, but also gave higher conductivity values than the conventional inkjet printed lines. Typically, conductivities up to 20% were revealed, which can be explained by a higher packing due to the capillary forces used for filling the channels.Moreover, we present an alternative technique to sinter in a selective method inkjet printed silver tracks on common polymer foils, by microwave radiation. This alternative technique is capable of a low temperature decomposition of the organic binding material that is around each metal nanoparticle. This results in the formation of conductive tracks. After applying this selective sintering technique, the features have a conductivity similar to conventional convection-radiation sintering, which is the most commonly used sintering technique at the moment.

Inkjet-printed silver tracks: low temperature curing and thermal stability investigation

In this contribution the curing behavior and conductivity development of several commercially available silver inks is discussed. In addition, the preparation and characterization of a silver particle ink that shows a curing temperature as low as 80 °C is described. Good to excellent conductivity values of 5 to 56% of bulk silver have been reached by using a very small amount of organic additives without any strong adsorbing groups such as amines, amides or mercapto groups. This low curing temperature opens new routes to produce conductive features on polymeric foils that have a low Tg, like PET. Furthermore, the temperature stability of silver tracks, prepared by inkjet printing different colloidal silver suspensions, was investigated. Hereto, the resistance was on-line measured during heating of the silver tracks, from room temperature to 650 °C.

Structuring of flexible substrates by the use of an aqueous solution based silver ink

Inkjet printing of conductive tracks is a major research topic for electronic applications. In this context silver is a widely used material. Especially the printing of silver tracks onto flexible substrates is of high interest but is often limited by the temperature applied in the post process. For many silver inks, the required temperatures to obtain metallic silver are much higher than the glass transition temperature of the substrate and thus the substrate is not applicable. Furthermore, nanoparticles in silver inks tend to clog the nozzles of inkjet printheads.We herein present an ink system, based on water soluble metal-organic molecules with high silver content. The ink transforms rapidly to elemental, conductive silver films at a temperature of 220 °C in only a few minutes. The physical properties of the solution are suitable for the inkjet technology. In addition to ink and printing characteristics, alternative approaches for the conversion of the silver ink with lower temperature induced stress on the substrate are discussed.

Inkjet Printing Silver-containing Inks

The fabrication of conductive silver tracks using Drop-on-Demand inkjet printing has been the focus of much research in the first decade of the 21st century. The appeal lies in inkjet's ability to produce patterns without using masks on a variety of substrates, with the goal being to produce highly conductive silver tracks on flexible, polymeric substrates. In order to achieve this, inks have been printed using silver nanoparticle suspensions, which require low curing temperatures. Inks that have been prepared from silver solutions have also been printed. This type of ink gives good conductivities (50% of bulk silver and higher) and can be chemically converted at room temperature, which allows low Tg polymeric substrates such as PET (Tg 75°C) to be used. This paper primarily discusses the obtained morphologies from the thermal, laser-assisted or chemical conversion of an inkjet printed silver solution ink.

Inkjet Printing of Narrow Conductive Tracks on Untreated Polymeric Substrates

Small conductive tracks are created by direct inkjet-printing of an ink with 30 nm silver particles onto flexible and transparent untreated polyarylate foils with a low surface energy. Lines with a diameter as narrow as 40 micrometers are obtained. After sintering, the conductivity of the obtained silver tracks is 13 to 23 % that of bulk silver. Such direct inkjet-printing may be applied in plastic electronics, where prestructuring or pretreatment of the substrate should be avoided to reduce production costs.

Ink‐jet Printing and Microwave Sintering of Conductive Silver Tracks

Printing techniques, such as ink-jet printing, are interesting alternatives to conventional photolithography for the production of electronic devices. The advantages of printing include the ease of mass production, low cost, and flexibility. Compared to other printing techniques (e.g., screen printing), ink-jet printing does not offer the same production speed. However, the unprecedented flexibility of ink-jet printing makes it very well suited for rapid prototyping applications. In addition, it allows the use of inviscid fluids, such as dilute polymer solutions or suspensions without added binders. A typical application involves the ink-jet printing of conductive tracks, for example, by using inks based on (in)organic silver or copper precursors. The precursor is reduced to the corresponding metal via a post-printing thermal annealing step. In most cases, however, the ink is a dispersion of noble-metal nanoparticles, usually silver or gold. A sintering step is necessary to render the tracks conductive. The use of nanoparticles reduces the sintering temperature due to their high surface to volume ratio. In the past, two different techniques have been used to sinter printed nanoparticle structures. Conventional radiation– conduction–convection heating is the most commonly used method, wherein the sintering temperatures are typically above 200 °C. Therefore many potentially interesting substrate materials, such as thermoplastic polymers or paper, cannot be used. In fact, one of the very few, if not the only organic substrate that can be used is (expensive) polyimide (PI). The long sintering times required—usually 60 min or more— also imply that the technique is not feasible for fast industrial production. As an alternative, a laser sintering method was developed. The laser follows the conductive tracks and sinters these selectively, without affecting the substrate. However, this method is costly and complex from a technical point of view. Thus, there is a clear need for a fast, simple, and costeffective technique that would allow the sintering of the printed structures by the selective heating of only the printed components. Microwave heating fulfills these requirements. Microwave heating is widely used for the sintering of dielectric materials and in synthetic chemistry. It offers advantages such as uniform, fast, and volumetric heating. Microwave radiation is absorbed due to coupling with charge carriers or rotating dipoles. The absorbed power per unit volume P is,

Direct ink-jet printing and low temperature conversion of conductive silver patterns

A drop-on-demand ink-jet printer has been used in the production of conductive silver tracks onto glass, polyimide, polytetrafluoroethylene, carbon and glass fibre reinforced epoxy substrates. Silver patterns were obtained from an organometallic solution by heat treatment at 150°C in air and were found to have resistivity values of 1.3 to 2 times the theoretical resisitivity of bulk silver. Printed track lateral resolution is a function of the ink/substrate wetting behaviour and a simple model is presented that relates track width to equilibrium contact angle. The influence of printing parameters and substrate surface properties on line quality is discussed.

A Combined Ink Jet Printing/Photo-reduction Process for the Fabrication of μm-size Conductive Tracks

Ink jet printing is a promising process for the production of cheap, flexible electronic circuits. Miniaturisation of such circuits to sizes smaller than currently attainable by conventional ink jet printing would present benefits in terms of performance, economics and the environment. Two laser-based techniques (selective laser ablation and photo-reduction) used in conjunction with ink jet printing to reduce feature size are demonstrated. Selective laser ablation of metallic silver tracks enabled feature sizes to be reduced to ∼5 μm, with good edge definition and little damage to glass substrates. Photo-reduction of organometallic silver salt deposits enabled features down to ∼10 μm, with no measurable heating of the substrate; enabling the use of a wide range of polymeric substrates. Both techniques show potential for reducing the feature size of ink jet printed deposits by an order of magnitude on flexible substrates.

Inkjet printed silver source/drain electrodes for low-cost polymer thin film transistors

Silver tracks for source/drain (S/D) electrodes in low-cost polymer thin film transistors (TFTs) have been realized through inkjet printing technique, using heavily n-doped silicon wafer with thermally grown silicon dioxide as the substrate and poly(3-hexylthiophene) (P3HT) as the channel material. Spin coating a layer of poly-4-vinylphenol (PVPh) onto the substrate was found to enhance the silver track uniformity and lower the cure temperature (from 300 to 210 °C). The surface roughness of the PVPh film was optimized to improve the device performance. The fabricated P3HT TFT with a channel length of 20 μm exhibited a saturation mobility of 3.5 × 10 −2 cm 2/V/s which was three times higher than that obtained in P3HT TFTs with gold S/D electrodes.

A Low Curing Temperature Silver Ink for Use in Ink‐Jet Printing and Subsequent Production of Conductive Tracks

AbstractSummary: A drop‐on‐demand ink‐jet printer has been used to print a silver‐organic solution onto glass substrates. Conductive silver tracks were obtained by heat treatment of the ink‐jet printed deposits at temperatures ranging from 125 °C–200 °C in air. Resistivity values were found to have dropped to two to three times the theoretical resisitivity of bulk silver after temperatures of 150 °C and above were used.Resistivity values of a silver‐based ink.magnified imageResistivity values of a silver‐based ink.

Inkjet-printed silver conductors using silver nitrate ink and their electrical contacts with conducting polymers

This paper presents a low-cost and direct-writing silver metallization process based on drop-on-demand inkjet printing technique. Silver nitrate dissolved in the mixture of water and dimethyl sulfoxide (DMSO) was used as a metal precursor for metallization. The fabricated silver films on polyimide substrate were characterized by means of scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and electrical measurements. The experimental results show that the inkjet-printed silver tracks have well-defined shapes. The resistivity of the printed silver tracks is around 1.5×10−5 Ω·cm, one order of magnitude larger than that of bulk silver, which is attributed to the porosities as well as the residual impurities. Two conducting polymers (CP), sulfonated polyaniline (SPANi) and poly(ethylene dioxythiophene)/poly(styrene sulfonic acid) (PEDOT/PSS), were inkjet-printed on the surface of the silver tracks to study electrical properties of the Ag–polymer contacts. The current–voltage measurement results show that the printed Ag–PEDOT/PSS and Ag–SPANi contacts exhibit ‘ohmic’ behavior.

Red Readers, Silver, High-Magenta, and Cyan Analog Sound Tracks—Review and Status

This paper reviews the benefits of silverless, cyan dye tracks to the motion picture industry, the status of red reader deployment in motion picture theaters, the effect of red reader characteristics on the sonic performance of silver and dye tracks, and the need for the intermediate step of first moving the industry to “high-magenta” color balance reapplicated sound tracks before changing over to silverless cyan dye tracks. In addition, an updated high-magenta and cyan dye track industry road map is presented.

Autoradiographic localization of opioid binding sites combined with immunogold detection of Leu-enkephalin, crustacean hyperglycaemic hormone and moult inhibiting hormone at the electron microscopic level in the sinus gland of the shore crab, Carcinus maenas.

Double labelling experiments were performed on the same tissue section at the electron microscopic level, in order to show the involvement of the opioid leucine-enkephalin (Leu-enk) in the modulation of crustacean hyperglycaemic hormone (CHH) mobilization. Both neuropeptides were stored in distinct axon terminals of the sinus gland of Carcinus maenas. A post-embedding immunogold cytochemical technique for Leu-enk, CHH and the CHH neurohormone related moult inhibiting hormone (MIH) was combined with a scintillator intensified autoradiographic method to demonstrate binding of the opioid antagonist [3H] naloxone. Ultrathin sections were successively incubated with antisera against Leu-enk, CHH or MIH, and the corresponding colloidal gold labelled antisera, followed by autoradiographic processing. At the ultrastructural level [3H] naloxone binding sites were easily recognized by their silver tracks after development. Opioid binding sites for [3H] naloxone were visualized only at membranes of CHH-containing axon terminals. These results provide morphological evidence for direct enkephalinergic control of CHH containing neurons in the sinus gland of C. maenas and are furthermore the first autoradiographic demonstration of opioid binding sites in the nervous system of invertebrates.

Optical Sound Recording with a Silicon Carbide Electroluminescent Diode

A system has been designed for the optical recording of sound using the light from a silicon carbide electroluminescent diode and ordinary films such as Plus X Reversal or Kodachrome II A with no special processing. The soundtrack was dye or silver track according to the use of color or black-and-white film. Standard projectors with ordinary exciter lamps, slit and detector systems were used. During recording, the diode was held in close proximity to the film and required no intervening optics. Diode operating currents and voltages were modest. Frequency response of 100 to 6000 Hz has been obtained with equalization on 16mm film; this was primarily limited by diode dimensions. The diode itself imposes a limit of 50 kHz. The light is yellow and is produced by a forward biased p-n junction which was about 1 by 2 mm for 16mm recording. The recording is variable density. The operating point for black-and-white film is at 10% transmission and at 70% transmission for color film at 9000 Å. Signal-to-noise ratio is about 30 to 40 dB for black-and-white film and about 20 dB for color film. Noise is mostly film noise.

SILVER AND GOLD SAND TRACK BAY WATER FLOW

SILVER AND GOLD SAND TRACK BAY WATER FLOW

A Comparison of Soundtrack Processing Methods for Color Release Positive Film

The problems of processing color release positive film to give a dye image and a silver soundtrack are discussed. The viscous image bleach method is described in some detail. The direct silver plus dye track produced by the viscous bleach method is compared with the track produced by the conventional redeveloped silver method.

A Phototube for Dye Image Sound Track<!--<xref ref-type="other" rid="fn1-10.5594_J11834">*</xref>-->

In view of the use of dye image sound track on new-type color film, a phototube has been developed with characteristics suitable for sound reproduction from these films as well as from ordinary silver tracks. It is a gas-filled, high-sensitivity phototube for use in standard reproducing equipment. The maximum spectral response occurs in the blue blue-green region of the spectrum. Details of construction, sensitivity, characteristic curves, spectral response, frequency response, and life are presented.