Showing papers on "Conductive ink published in 2012"

Inkjet printing of conductive materials: a review

Abstract: Purpose – The purpose of this paper is to present an exhaustive review of research studies and activities in the inkjet printing of conductive materials.Design/methodology/approach – This paper gives a detailed literature survey of research carried out in inkjet printing of conductive materials.Findings – This article explains the inkjet printing process and the various types of conductive inks. It then examines the various factors that affect the quality of inkjet printed interconnects such as printing parameters, materials and substrate treatments. Methods of characterising both the inkjet printing process and the electrical properties of printed conductive materials are also presented. Finally relevant applications of this technology are described.Originality/value – Inkjet printing is currently one of the cheapest direct write techniques for manufacturing. The use of this technique in electronic manufacturing, where interconnects and other conductive features are required is an area of increasing rele...

Roll-to-roll compatible sintering of inkjet printed features by photonic and microwave exposure: from non-conductive ink to 40% bulk silver conductivity in less than 15 seconds.

Abstract: A combination of photonic and microwave flash exposure is used to sinter inkjet printed silver nanoparticles. This approach leads to conductive features on polymer substrates in short times that are compatible with roll-to-roll production. The sequential process of sintering the as-printed features revealed a final conductivity of 40% of bulk silver, in less than 15 seconds. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stability and Efficiency of Screen-Printed Wearable and Washable Antennas

Abstract: Wearable antennas, integrated into garments, are prone to get dirty. Therefore, for the first time in literature, washable antennas are proposed by covering textile antennas by a breathable thermoplastic polyurethane coating, protecting the antennas against water absorption and corrosion. The washability of coated wearable antennas produced by screen printing conductive ink onto a textile substrate is compared to coated wearable antennas based on an electrotextile, analyzing performance in terms of their reflection coefficient and radiation efficiency before and after washing. The combination of screen printing and coating provides stable antenna performance with sufficiently high radiation efficiency after several washing cycles.

Electrical Conductive Textiles Obtained by Screen Printing

Abstract: Due to the emergence of smart textiles and wearable textile systems, the need for electrically conductive textiles has become increasingly clear. Often this conductivity is achieved by integrating metal particles, fibres or yarns into textiles or by coating a textile with a metallic layer. In this research, the potential of another method is explored, namely screen printing a textile with conductive ink. This printing technique is an interesting alternative because it is flexible and cost effective. In this study the conductivity was investigated by measuring the square resistance at different stages (i.e. after printing, abrading and washing, respectively). The printed textiles studied herein exhibit good electrical properties after printing and abrading, respectively. However, after twenty washing cycles, the conductivity decreased considerably. Therefore, in order to improve washability, a protective polyurethane layer was put on top of the printed samples, which resulted in the good conductivity of the fabrics, even after washing.

Preparation, characterization and reaction mechanism of a novel silver-organic conductive ink

Abstract: A novel silver-organic conductive ink with no particles, consisting of silver–amide complex dispersed in glycol–water mixture, was developed in a simple way. The reaction mechanism during sintering was also studied and a multi-mechanism was found for the first time. Silver ions in solution can be reduced by glycol to metallic silver following the typical polyol process. Meanwhile, silver–amide complex will decompose to silver oxide, and is then immediately reduced by glycol. The result indicates that the silver oxide reduction mechanism plays a major role in the whole reaction. The type of amine has a great influence on the properties of the ink. When adding a proper amount of γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560), both the conductivity and adhesion of sintered silver film will be improved. Microstructures of the silver film were observed, and a multi-layered structure was detected. The relationships between structure and resistivity and adhesion were also researched. After being filled into a marker and drawn on polyimide (PI) film, the conductive ink was sintered at 150 °C for 1 hour using an oven, and the resistivity of the silver film was 18 μΩ cm, about 11 times that of bulk silver.

Ohmic Curing of Printed Silver Conductive Traces

Abstract: Ohmic heating was demonstrated as a novel curing method (or curing enhancement) useful in decreasing the resistivity of conductive traces printed with both micro- and nanoparticle-loaded inks while (1) only locally heating the substrate and (2) curing in a matter of seconds compared with the range of 30 min to 1 h required by traditional oven-curing. In one experiment using traces composed of microparticle ink, which required initial air-drying as a preprocess step, application of an ohmic curing cycle resulted in resistivity of 80 nΩ m, roughly six times that of bulk silver. In a second experiment employing nanoparticle inks, which required an initial thermal cure as a preprocess, a resistivity of 43 nΩ m, roughly three times that of bulk silver, was attained after the application of an ohmic curing cycle. Electrical characterization of the ohmic curing process was performed in real time to understand the impact of cycling and duration on the resulting conductivity. Finally, the effect of printed trace length on the ohmic curing process was explored and found to have a near-linear relationship with the reduction in resistance when the applied electrical current was normalized to measured resistance. The microstructural changes which occurred as a result of ohmic curing such as particle sintering and grain growth were characterized by scanning electron microscopy. The results presented in this work demonstrate the use of ohmic heating to overcome temperature limitations imposed on a thermal curing process by substrate material properties or other sources.

A Simple Process for Synthesis of Ag Nanoparticles and Sintering of Conductive Ink for Use in Printed Electronics

Abstract: Various-sized Ag nanoparticles capped with oleylamine were synthesized by means of a thermal decomposition process for low-temperature electronic devices. The Ag nanoparticles, which had diameter of 5.1 nm to 12.2 nm, were synthesized in incubation and ripening stages related to nucleation and growth. After the Ag nanoparticles were made into ink with a proper solvent, inkjet printing and thermal sintering methods were used to form a metal thin film with thickness of 100 nm. A type of thermal sintering related to percolation transformation and surface sintering was conducted at a temperature much lower than the melting point of bulk Ag. The electrical resistivity was examined with the aid of a four-point probe system and compared with the resistivity of bulk Ag, showing that the Ag film had much higher resistivity than bulk Ag. To improve the electrical stability and properties, we applied hexamethyldisilazane (HMDS) surface treatment to the substrate and dipped the as-deposited films into methanol. Both treatments helped to diminish and stabilize the resistivity of the printed conductive films.

Resistivity transition mechanism of silver salts in the next generation conductive ink for a roll-to-roll printed film with a silver network

Abstract: As the small size display market rapidly expands with the advent of smart phones and tablets, the industrial demand for a low cost transparent conductive film instead of an ITO sputtered one has expedited the development of a roll-to-roll printed one with a low temperature processable and highly conductive ink. The conventional conductive ink based on metallic nanoparticles capped with a polymeric dispersant, however, has difficulties in achieving high conductivity at a low curing temperature due to the unwanted residue of a polymeric dispersant. Therefore, a new kind of conductive ink was developed, where a silver salt replaces the role of a polymeric dispersant and also enriches the overall metallic content. The key to this new generation of conductive ink leans on the selection of a low temperature processable silver salt and the selection process of silver salts was on the basis of their thermogravimetric thermograms with the common belief that the thermogravimetric thermogram of a silver salt is coupled with its resistivity transition and final resistivity. In contrast to this common belief, our results show that the thermogravimetric behaviours of silver salts have little influence on their resistivity transition and final resistivity. With our comprehensive studies using various isomeric silver salts, we here suggest that the more persuasive and leading factors in determining the resistivity transition behaviour of a silver salt are stack integrity, phase transition, and the exothermic band in the differential scanning calorimetric thermogram. The next generation conductive ink with the most suitable silver salt was gravure-offset printed on a transparent and flexible film. Its sheet resistance after being cured at 150 °C is as low as 1 Ω □−1 with the line width of 20 μm and the optical transmittance of 85% and above.

Bondable conductive ink

Abstract: A bondable conductive ink comprising carbon nanotubes, larger diameter conductive particles having at least one dimension of at least 100 nanometers which are not carbon nanotubes, a polymer, and a solvent, and a method of producing this bondable conductive ink. The ink is highly suitable for producing circuit assemblies having non-conductive substrates upon which printed conductors, formed from the bondable conductive ink, may be easily and selectively interconnected to another circuit assembly device, and/or apparatus.

Control of chemical kinetics for sub-10 nm Cu nanoparticles to fabricate highly conductive ink below 150 °C.

Abstract: To steadily apply conductive inks that contain Cu nanoparticles (NPs) to inkjet printing of patterns at temperatures below 150 °C, the size of the Cu NPs must be reduced. Therefore, we obtained Cu NPs in the range of 9-33 nm, and we studied how their size changes. The variation of the chemical reaction rate changed the size of the Cu NPs for two main reasons. First, the fast transition rate of the Cu precursors at high pH values raises the supersaturation level of the Cu precursor above that of a process with a slow transition rate. The high supersaturation level is generally attributed to the small Cu nuclei and the slow growth caused by their density. Second, the high viscosity of the reaction solution, which occurs because polyvinyl pyrrolidone (PVP) causes an increase in the repulsive force, slows the growth of the Cu NPs at high pH values. The recrystallization temperature of the 9 nm Cu NPs was reduced to 108 °C, and a low specific resistivity of 45 μΩ cm was achieved using the conductive ink prepared with 9 nm Cu NPs at 120 °C. This temperature is significantly lower than those reported for other Cu NP inks. Hence, Cu NP conductive ink could considerably reduce costs because of its apparently low temperature, resolving the main bottleneck of inkjet printing on flexible (polymeric) substrates.

Led light disposed on a flexible substrate and connected with a printed 3d conductor

Abstract: An example includes subject matter (such as an apparatus) comprising a planar substrate including a first surface that is planar, at least one bare light emitting diode (“LED”) die coupled to the substrate and conductive ink electrically coupling the at least one bare LED die, wherein the conductive ink is disposed on the substrate and extends onto a surface of the LED that is out-of-plane from the first surface.

Conductive material and process

Abstract: A method for making a conductive network of sintered silver comprises preparing a conductive ink comprising a silver compound and a binder; depositing the conductive ink on a substrate and applying an external energy source to the deposited conductive ink to dry the ink; and applying an external energy source to the dried ink to decompose the ink to elemental silver and to sinter the elemental silver into a conductive network.

Synthesis and characterization of highly conductive Sn–Ag bimetallic nanoparticles for printed electronics

Abstract: To synthesize low-cost, highly conductive metal nanoparticles for inkjet printing materials, we synthesized Sn–Ag bimetallic nanoparticles using a polyol process with poly(vinyl pyrrolidone). Because a surface oxidation layer forms on Sn nanoparticles, various compositions of Sn–xAg [x = 0, 20, 40, 60, 80, 100 (wt%)] nanoparticles were synthesized and characterized for the purpose of removing the β-Sn phase. The results of XPS, TEM, and XRD analyses confirm that the formation of a bimetallic phase, such as Ag4Sn or Ag3Sn, hinders the β-Sn phase and, consequently, leads to the removal of the surface oxidation layer. To measure the sheet resistance of various compositions of Sn–Ag nanoparticles, we made the ink that contains Sn–Ag by dispersing 10 wt% of Sn–Ag nanoparticles in methanol. The sheet resistance is decreased by the conductive Sn–Ag phases, such as the fcc, Ag4Sn, and Ag3Sn phases, but sharply increased by the low-conductive Sn nanoparticles and the surface oxidation layer on the Sn nanoparticles. The sheet resistance results confirm that 80Ag20Sn and 60Ag40Sn bimetallic nanoparticles are suitable candidates for inkjet printing materials.

Jet conductive ink

Abstract: The invention relates to jet conductive ink, which is film printing electronic paste and is suitable for ink jet printing, and belongs to the field of printed electronics. The jet conductive ink comprises the following components in portion by weight: 1 to 29 portions of conductive particles, 60 to 85 portions of solvent, 1 to 5 portions of humectant, 1 to 5 portions of pH regulator, 1 to 5 portions of surfactant, and 1 to 3 portions of bonding material. The cost of a method for the jet conductive ink is low, and the conductive silver in the conductive paste is reduced to less than 29 portionsby weight; the method has a mild post treatment process, and the post treatment temperature of a printed product is reduced to about 100 DEG C by using nano silver to replace micro silver; and through an ink jet printing mode as required, the thickness of an obtained conductive film is about 1 micron, and the resistance reaches about 1 ohm.

A systematic approach for the design, fabrication, and testing of microstrip antennas using inkjet printing technology

Abstract: We present a systematic approach for producing microstrip antennas using the state-of-the-art-inkjet printing technique. An initial antenna design based on the conventional square patch geometry is adopted as a benchmark to characterize the entire approach; the procedure then could be generalized to different antenna geometries and feeding techniques. For validation purposes, the antenna is designed and simulated using two different 3D full-wave electromagnetic simulation tools: Ansoft's High Frequency Structure Simulator (HFSS), which is based on the Finite Element Method (FEM), and CST Microwave Studio, which is based on the Finite Integration Technique (FIT). The systematic approach for the fabrication process includes the optimal number of printed layers, curing temperature, and curing time. These essential parameters need to be optimized to achieve the highest electrical conductivity, trace continuity, and structural robustness. The antenna is fabricated using Inkjet Printing Technology (IJPT) utilizing Sliver Nanoparticles (SNPs) conductive ink printed by DMP-2800 Dimatix FujiFilm materials printer.

Preparation of stable aqueous conductive ink with silver nanoflakes and its application on paper‐based flexible electronics

Abstract: A new kind of stable aqueous conductive ink with silver nanoflakes was developed, which was also used to fabricate conductive patterns on weighing paper for flexible electronics by direct writing. Silver nanoflakes of different sizes were characterized by transmission electron microscopy. The physical properties of the conductive ink were investigated by a dynamic contact angle system, Ubbelohde viscometer, and a surface tension instrument. Conductive properties of paper-based conductive patterns were also investigated by 4-point probe, scanning electron microscopy, X-ray diffraction and Uscan explorer with a 3D profilometer system. It is demonstrated how the formulation of conductive ink affects the surface morphology, microstructure conductivity, and line width of conductive patterns. It can be obtained that the paper-based conductive patterns have low resistivity. Especially, when the sintering condition is 200 °C for 20 min, the resistivity can be down to 9.4 μΩ•cm. The application of the ink on an antenna for radio frequency identification was also studied. Copyright © 2011 John Wiley & Sons, Ltd.

Method and system for distributed network of nanoparticle ink based piezoelectric sensors for structural health monitoring

Abstract: The disclosure provides in one embodiment a system for monitoring structural health (172) of a structure (30). The system has a structure to be monitored for structural health (172). The system further has a distributed network of nanoparticle ink based piezoelectric sensor assemblies (120) deposited onto the structure (30). Each assembly has a plurality of nanoparticle ink based piezoelectric sensors (110) and a plurality of conductive ink power and communication wire assemblies (140) interconnecting the plurality of sensors (110). The system further has an ink deposition apparatus (142) depositing the distributed network of nanoparticle ink based piezoelectric sensor assemblies (120) onto the structure (30). The system further has an electrical power source (178) providing electrical power to the distributed network (120). The system further has a data communications network (179) retrieving and processing structural health data (174) of the structure (30) via one or more signals from the sensors (110).

Agranular transparent conductive ink and its preparation method

Abstract: The invention discloses an agranular transparent conductive ink which can sinter at low temperature and has good stability, and a preparation method thereof. The conductive ink mainly consists of a solvent organic amine or ammonia water and an organic silver salt. During preparation, one of the solvent organic amine or ammonia water or more than one of other solvents are only needed to be mixed well, then an effective quantity of the organic silver salt is added, and after complete dissolution and dispersion, the conductive ink can be obtained. The conductive ink can form a pattern or a wet film by means of printing or coating, wherein, the organic silver part can be reduced to silver particles in the following heat treatment process so as to form a conductive pattern or conductive film. The conductive ink obtained through the method of the invention can has high stability without adding an extra protective agent. The preparation method put forward in the method has the advantages of simple process, mild reaction condition, short reaction time and low preparation cost.

Golf ball with rfid system

Abstract: A golf ball has a radio-frequency identification (RFID) circuit for storing ID information therein, the RFID circuit formed of conductive ink; and an antenna for communicating by using radio frequency signals, the antenna connected to the RFID circuit. The antenna may be formed of conductive ink or paste. The RFID circuit and the antenna may be formed on the surface of the golf ball. The golf ball may further include a core layer, a cover layer disposed on the outside of the core layer, and optionally, an intermediate layer disposed between the core layer and the cover layer. The core or intermediate layer has a groove on the surface thereof, and the RFID circuit and the antenna may be formed within the groove.

Transparent conductive coating film, transparent conductive ink, and touch panel using transparent conductive coating film or transparent conductive ink

Abstract: A transparent conductive coating film or a transparent conductive ink, which contains at least metal nanowires, is configured such that the ratio of bent nanowires among the metal nanowires is 10% or less. The transparent conductive coating film is configured so as to have a surface resistivity of 150 Ω/□ or less and a haze value of 1.0% or less. The transparent conductive ink is configured so that the conductivity in the transparent conductive ink is 1 mS/cm or less.

Effect of the different shapes of silver particles in conductive ink on electrical performance and microstructure of the conductive tracks

Abstract: The electrical performance of the ink-jet printed conductive tracks composed of silver particles was investigated. Three different shapes silver particles were synthesized via chemical reduction method in the presence of poly vinyl pyrrolidone, and then they were used to study the shape influence on the electrical property and thermal stability of the conductive tracks. The resistivity variation and microstructure of the silver conductive tracks was monitored as a function of fillers content using a four-point probe and scanning electron microscopy as well as thermal analysis. In addition, we proposed the possible formation mechanism of conductive tracks with different fillers. It demonstrated that the conductive tracks filled with silver nanorods and nanoparticles could achieve the volume electrical resistivity of ~3.2 × 10−5 Ω cm after sintering at 160 °C for 15 min. Finally, we fabricated highly conductive silver patterns on a glass substrate by ink-jet printing.

Washable screen printed textile antennas

Abstract: The wireless communication systems are applied in different applications such as computers, mobile phones, satellites and antennas for off-body communication. A lot of efforts were made to have the antennas in a smaller size, flat and with better performance. In the last decade the rigid antennas are replaced with textile in order to be flexible and to be integrated into garments in order to have wearable textile systems. The textile antennas can find use in medical, military and first responders monitoring. The conductivity of the antennas can be achieved by using coated textile materials which are available in the market, conductive threads for embroidery or conductive inks. When using the conductive coated textile it is necessary to cut the patch in the desired pattern but using a simple cutting tool sometimes is not very precise and accurate. Thus in our study we decide to screen print with silver conductive inks on Polyester and Cotton/Polyester substrates. The screen printed antennas are than washed in order to conform that antennas for off-body communication integrated in garments can be easily washed five times.

Nano copper-tin alloy conductive ink and preparation method and usage of nano copper-tin alloy conductive ink

Abstract: The invention belongs to the technical field of material chemistry, relates to conductive ink, and particularly relates to nano copper-tin alloy conductive ink and a preparation method and usage of the nano copper-tin alloy conductive ink. Nano copper-silver alloy is replaced by nano copper-tin alloy to be used as conductive filler in the conductive ink, sintering temperature of the conductive ink is lowered, and when the nano copper-tin alloy conductive ink is compared with nano copper-silver alloy conductive ink, antioxidant capacity of the conductive ink during sintering is improved, mechanical property and solderability of a conductive circuit formed after sintering of the conductive ink are improved, and the problem of silver ion migration is avoided. Further, since rare earth metal elements are doped in the nano copper-tin alloy, grain boundary of the nano copper-tin alloy is increased, electron scattering power is increased, and conductivity is improved as compared with that of nano copper alloy. On the other hand, tin is much cheaper than silver, so that raw material cost of the nano copper-tin alloy conductive ink is reduced.

Collagen peptide-coated copper nanoparticles, collagen peptide-coated copper nanoparticle dispersion, method for preparing collagen peptide-coated copper nanoparticles, conductive ink, method for preparing conductive film, and conductor wiring

Abstract: According to the present invention, there are provided copper nanoparticles having an average particle diameter of 50 nm or less and having excellent oxidation resistance and dispersion stability. In the collagen peptide-coated copper nanoparticles of the present invention, the copper nanoparticles having an average particle diameter of 50 nm or less are coated with collagen peptides having a weight average molecular weight of 10000 or less.

Evaluation of Coatings Applied to Flexible Substrates to Enhance Quality of Ink Jet Printed Silver Nano-Particle Structures

Abstract: Different types of the commercial surface treatment InkAid have been evaluated as a surface treatment to enhance print quality of silver nano-particle ink structures printed on polyimide and polyethene substrates. Originally these coatings were designed to be applied on substrates for graphical ink jet printing. On the coated polyimide and polyethene substrates lines of different widths have been printed using a Dimatix materials printer together with silver nano-particle ink manufactured by Advanced Nano-Products. The prints have then been evaluated in terms of print quality and resistivity before and after sintering. The results show that the application of these coatings can improve the print quality considerably, making it possible to print lines with a good definition, which is not otherwise possible with this type of ink on this substrate types. It has been found that the semi-gloss coating provides the best results, both in terms of print quality as well as the lowest resistivity. The resistivity on polyethene is 3.5×10-7 Ωm at best when sintered at 150°C and for polyimide 8.9×10-8 Ωm sintered at 200°C. This corresponds to a conductivity of about 4.5% and 18% of bulk silver, respectively. It can be concluded that applying such polyvinylpyrrolidone (PVP)-based coatings to polyethene and polyimide will increase the print quality quite substantially, making it possible to print patterns with requirements of smaller line widths and more details than what is possible without coating.

Preparation of High-Performance Conductive Ink with Silver Nanoparticles and Nanoplates for Fabricating Conductive Films

Abstract: A novel preparation method for a high-performance conductive ink which consisted of silver nanoplates, spherical silver nanoparticles, and epoxy resin was developed. Silver nanoparticles and nanoplates were synthesized via chemical reduction method in the presence of poly (vinyl pyrrolidone) (PVP). The prepared silver ink exhibited a remarkable electrical, thermal stability, and mechanical properties, which were confirmed by the four-point probe method, thermogravimetric analysis (TGA), and the three-point bending testing. We demonstrated the influence of sintering temperatures and time on the electrical resistivity. After sintering at 150°C for 15 min, the conductive film was able to achieve the volume electrical resistivity of (3–4) × 10−5Ω · cm.

Rheology of conductive ink flow for printed electronics on a microfluidic chip

Abstract: Printed electronics have recently attracted extensive attention due to their superior productivity to conventional semiconductor fabrication methods. To develop printing devices optimized for printed electronics, numerical studies on ink flows are often necessary, and, therefore, it is critical to provide accurate ink properties for reliable numerical results. However, it is difficult to find such data in literature since inks for printed electronics contains conductive metallic nanoparticles and they are not only non-Newtonian but expensive. Thus, we propose utilizing a microfluidic chip to investigate rheological properties of conductive inks. By using micro particle image velocimeter along with an immersion oil technique, we examine the flow characteristics of two commercial conductive inks containing Ag nanoparticles on microfluidic chips. We found that the ink flows show a stronger shear-thinning behavior as the Ag content increases. Finally, suitable rheological models applicable to numerical simulations for those inks are suggested after comparing the experimental data to frequently used rheological models.