Silver nanoparticle ink technology: state of the art

SN Applied Sciences

In printed electronics, conductive traces are often produced by printing inks of silver nanoparticles dispersed in solvents. A sintering process is usually needed to make the printed inks conductive by removing the organic dispersants and allowing metal-to-metal contacts among nanoparticles for atomic diffusion and neck formation. It has been challenging to sinter silver nanoparticle inks in a thermal oven at a temperature < 150 °C to avoid thermal damage to the plastic substrate while achieving desired conductivity. This work presents a simple, yet effective way to sinter a silver nanoparticle ink below 120 °C (even at 80 °C) by exposing the printed ink to water vapor in the oven. The results consistently show a significant reduction in line resistivity for the samples sintered in a moist oven compared to those sintered in a dry oven. For example, the measured resistivity can become 9.32 μΩ cm (5.90 times that of bulk silver) when a silver nanoparticle ink is sintered with water vapor at 120 °C for 30 min. Hence, solvent vapor-assisted sintering of metal nanoparticle inks can become an enabling approach to broadening the product range of printed electronics.

Scientific Reports

Development of cost-effective and environmentally friendly manufacturing methods will enable important advances for the production of large-scale flexible electronics. Laser processing has shown to be a promising candidate that offers a fast and non-destructive way to produce highly conductive patterns on flexible substrates such as plastics. However, an emerging option with a lower environmental impact is instead the use of cellulose-based flexible substrates, such as paper. In this work we investigate the use of laser sintering of silver nanoparticle inks, which were inkjet-printed on three different types of paper. Patterns with a high conductivity could be manufactured where a special care was taken to prevent the substrates from damage by the intense laser light. We found that the best results was obtained for a photopaper, with a conductivity of 1.63 * 10 7 S/m corresponding to nearly 26% of the bulk silver conductivity. In addition, we demonstrate laser sintering to fabricate a fully functional near field communication tag printed on a photopaper. Our results can have an important bearing for the development of cost-effective and environmentally friendly production methods for flexible electronics on a large scale.

2017

Researchers have been focusing on printed electronics as they are cheap, occupy small volumes, have very high speed and can be changed easily. Silver nanoparticle plays a key role in flexible printing at room temperature and other electronic applications. Use of nanoparticle ink enables to design wearable biosensor systems for health monitoring. Advances have been made towards a new generation of wearable devices that can fit themselves to the human body, not only help to identify and track physical activity of the wearer, but also provide communication capability which allows us to access data in real-time using another medium. This paper outlines the key role of silver nanocrystals as an ink used for flexible materials as well as the advances of wearable devices and their applications in electronics and medical field.

International Symposium on Microelectronics, 2010

Miniaturization and increased complexity of electronic devices are two major trends in the electronic industry. Recent research indicates that inkjet printing can be successfully used in building smaller and more complex structures. This paper describes new methods for generating inkjet printable dispersions of highly dispersed silver and gold nanoparticles. The patterns deposited with a ‘drop-on-demand’ inkjet printer were sintered at different temperatures and converted into thin, highly conductive metal layers. In the case of silver, we show that the film microstructure and electrical resistivity can be tailored by using bimodal particle size distributions.

Journal of Materials Research, 2009

An environmentally friendly route to prepare stable concentrated aqueous dispersions of silver nanoparticles is described. It was found that Arabic gum, a well known stabilizing agent, can also rapidly and completely reduce Ag2O to metallic silver in alkaline solutions (pH &gt; 12.0) and elevated temperature (65 °C). The average size of the silver nanoparticles could be tailored from 10 to 30 nm by varying the experimental conditions. By hydrolyzing either enzymatically or chemically the polysaccharide, it was possible to isolate dispersed silver nanoparticles suitable for both biological and printable electronics applications. For the latter purpose, concentrated dispersions of silver particles were prepared and used for depositing thin uniform layers, which could be sintered into conductive films at low temperatures.

Journal of Nanotechnology in Diagnosis and Treatment

This study investigates the synthesis of mono metallic (copper and silver) and bi-metallic (copper/silver core/shell) conductive nanopigments for inkjet printing. Polyethylene glycol (PEG) was used as a main reducing agent followed by polyvinylpyrrolidone (PVP) as a capping and dispersing agent. From the XRD, TEM, and SEM analyses, the synthesized mono and bi metallic particles were con?rmed to be in a nano scale with particle size 7, 8.5 and 15.5 nm for copper, silver and copper/silver core/shell, respectively. The prepared nanopigments were included in inkjet ink formulation and printed on flexible polyethylene terephthalate (PET) films. The printed ink films were sintered at various temperatures (110, 150, 200). The results revealed that the resistivity of these particles was reduced by sintering and the resistivity of Cu, Ag and Cu/Ag patterns sintered in air at 200 ºC for 30 min were 3.1, 2.99 and 4.14 µ?-cm, respectively. The obtained results were in a good agreement with the ...

Chemical Engineering Journal, 2019

An ideal silver precursor ink should be highly stable, transparent, and compatible with a broad range of substrates and facile fabricating techniques to provide a uniform electrodes with bulk conductivity at mild temperatures (<100 °C) for high performance electronic applications. Herein, we report a facile chemical route to develop the robust silver precursor ink having long stability, which possesses key characteristics of an optimal ink and provides a practical realization in flexible electronics via multiple techniques. The obtained transparent silver ink offers an unambiguously unique and economical approach towards printable electronic devices. The silver electrodes are fabricated by silver ink nozzle-jet printing and ink-pen writing that demonstrate remarkable conductivities (10 6-10 7 S/m) close to bulk silver (~10 7 S/m) after annealing at 70-100 °C. The adhesion and conductivity of printed silver is highly stable in various mechanical bending. High quality nano-crystalline and pin holes free silver patterns are observed on flexible PET and PI substrates. The probable mechanism for formulated silver ink is elucidated. The precursor ink formulation process can possibly eliminate the need for costlier methods such as gravure printing and paves the way to industrial manufacturing of prudent electronic devices.

Materials Chemistry and Physics, 2008

Highly monodispersed silver nanoparticles were successfully synthesized by thermolysis of silver alkanoate precursors and were characterized by X-ray diffraction, TGA/DTA and transmission electron microscopy. The results showed that these nanoparticles exhibit spherical shape with FCC crystal structure. The relationship between the carbon chain length and the monodispersity of the nanoparticles was investigated. Furthermore, the size of the particles was controlled by varying the concentration of the stabilizing surfactants. The silver nanoparticles were easily re-dispersed into n-tetradecane and printed onto various substrates using a Microfab head with a single nozzle. The ink-jet printed patterns were sintered at 250 • C and their electrical resistivity was about 6 cm.

IOP Conference Series: Materials Science and Engineering

Printed electronics technology is one of the most dynamic in the world, allowing for the low-cost fabrication of electronic networks on textile substrates using the inkjet printing technique which is commonly used in various industries. In the field of formulation of conductive inks, silver nanoparticles are generally used as precursors that confer electrical conductivity to the printed patterns. In the present work, we synthesized silver nanoparticles by an ecological reduction method and then dispersed them in a PEG/Glycerol mixture to prepare a conductive ink. The silver nanoparticles were characterized by X-ray diffraction (XRD), as well as the morphology of the printed silver tracks was characterized by SEM. The developed ink was then successfully printed on a piece of pre-treated cotton fabric to produce flexible electronic components on the textile.

RSC Advances

Systematic study of printing scheme and sintering time and temperature on the conductivity of silver flims on glass.

Inkjet-printed metal films are important within the emerging field of printed electronics. For large-scale manufacturing, low-cost flexible substrates and low temperature sintering is desired. Tailored coated substrates are interesting for roll-to-roll fabrication of printed electronics, since a suitable tailoring of the ink-substrate system may reduce, or remove, the need for explicit sintering. Here we utilize specially designed coated papers, containing chloride as an active sintering agent. The built-in sintering agent greatly assists low-temperature sintering of inkjet-printed AgNP films. Further, we examine the effect of variations in coating pore size and precoating type. Interestingly, we find that the sintering is substantially affected by these parameters.

2021

Silver nanowires (AgNWs) are known to be used for printing on rigid as well as flexible surfaces. Here we have developed a systematic approach for using AgNWs synthesized by the polyol method for printing on flexible surfaces using a simple inkjet printing method. Optimized ink formulation used in this work comprises a mixture of Ag NWs suspended in ethylene glycol directly taken after synthesis and isopropyl alcohol. Using such formulation saves time and loss of material while transferring to other solvents, which is the usual practice. The printed patterns demonstrate high conductivity and stability over many months, which can revolutionize the applications of functional nanomaterials in low-cost printed electronics. The importance of fragmentation of nanowires only to achieve specific aspect ratios, to facilitate easy jetting and to prevent clogging is demonstrated. Varied concentrations (10 mg mL−1 to 50 mg mL−1) of Ag NWs are used in ink formulations in order to print highly co...

Journal of Materials …, 2007

Silver nanoparticles were synthesized from silver nitrate and methanol and stabilized by the use of nitrocellulose and 3-aminopropyl alcohol. These colloidal solutions were found to be very stable, with no evidence of silver aggregation over a period of 9 months, and displayed ...

Journal of Materials Science: Materials in Electronics, 2017

its high optical transparency and electrical conductivity [3]. To fabricate ITO transparent electrodes, vacuum based processing techniques are utilized, which requires a high temperature in the processes [4]. Hence, the manufactured electrodes through these processes have a high cost because of their complex process as well as cannot fabricate through e-printing processing techniques. For a future display, wearable electronic age is coming. To develop wearable electronics, many researchers are searching novel transparent and flexible electrode materials [5, 6], which can be fabricated by utilizing printed techniques such as ink-jet, screen, and roll-to-roll printing methods. For the rising electronic industry, a new material based electrode to replace the ITO is essentially required; hence these investigations are mainly focused on conductive polymers and conductive nanostructures materials [7]. However, the polymer transparent electrodes are restricted in their application due to their low conductivity [8]. In recent years, many researchers are studying 2D nanostructure, and finding the candidate for future transparent electrode materials such as nanowires (NWs), nanotubes, and nanorods [2, 9-12]. Especially, the carbon nanotubes are getting the spotlight in the wearable electronics due to their high conductivity, good electrochemical properties, and chemical inertness [12, 13]. The 2D nano-structures are also more transparent than the commercialized 3D structure materials. However, nanotube films have yet to achieve the performance compared to ITO films in terms of transmittance and sheet resistance [11]. Alternatively, the silver (Ag) NWs have been proposed as another candidate and have been reported to have the potential to replace and surpass ITO [14, 15] because of their intriguing electrical and optical properties [16]. Furthermore, Ag NWs are considering as important material in flexible electronics due to Ag is the highest electrical conductivity among all the metals. Using Abstract In recent, silver (Ag) nanowires (NWs) have received much attention as an alternative to indium tin oxide (ITO) for transparent electrode application in printed and transparent electronics. However, Ag NWs have its breakup problem by joule heating during current. To overcome this problem, this paper demonstrates a mesh type electrode based on Ag nanoparticles, which is fabricated on PET substrate through an ink-jet printing technique. The proposed electrode has a low resistance of 108.5 Ω/sq and a good optical transparency around 92% at 300-800 nm. It has a relationship that the sheet resistance drops with the decrease of transparency due to depending hole size and the best curing temperature is found to be 120 °C. It also demonstrate an excellent flexible stability, showing < 2% resistance change after over 100 bending cycles. These resistance and transparency are similar with that of commercially ITO electrode, and are superior to other alternatives such as carbon nanotube electrodes. The proposed electrode can be considered as a commercial electrode to as an alternative to ITO electrode.

physica status solidi (a), 2016

Silver nanoparticle inkjet inks are commonly used to print electrically conductive patterns, such as sensors or electrodes in organic light emitting diodes (OLEDs) or organic photovoltaic devices (OPVs). After printing, a sintering step is required to transform the printed layer into an electrically conductive one. Gaining more insight into the occurring phenomena during this post-treatment step is necessary when applying different kinds of inkjet ink. Therefore, in this work the commercially available silver nanoparticle inkjet ink Metalon JS-B30G from Novacentrix is characterised during the different stages in the printing and thermal sintering sequence. The pre-printing and post-sintering characterisation proves that the inkjet ink used has got the right material parameters, such as viscosity and particle size. Silver layers with sheet resistances of 40 mV/sq were obtained with an average roughness lower than 10 nm. The experiments performed show the different stages during the thermal sintering procedure. Based on this, suitable thermal sintering parameters are defined leading to application of these conductive silver layers in OLEDs.