Silver Nanoparticle Synthesis Using an Inkjet Mixing System

Journal of Manufacturing Processes, 2020

Ink properties play a critical role in different printing techniques. However, it is not straightforward to correlate ink properties to the printing results. In this study, several parameters were identified and analyzed to evaluate the droplet behavior in electrohydrodynamic inkjet printing. More specifically, the effects of metallic nanoparticle sizes in the ink formulation were explored through the analysis of droplet impact behaviors. These parameters include droplet wetting diameter, height, initial impact velocity, and contact angle. With the assistance of machine vision, a high-speed camera captured a sequence of images, which were analyzed to extract the aforementioned parameters. Under fields of gravitational force with/without electric force, four phases of ink droplet behaviors were identified. Our data suggest that with an electric force field, particle size dominates the droplet behavior in respect to contact angle and wetting diameter. The increase of particle size decreased the droplet wetting diameter with an electric field, while increased the droplet wetting diameter without the electric field applied. Larger droplet size resulted in higher bouncing frequency and lower droplet height. Furthermore, under both gravitational and electrical fields, the droplet with medium particle size (average diameter of 276 nm) had a higher impact velocity than that with small (average diameter of 140 nm) and big (average diameter of 1517 nm) particle sizes. This study contributes to fundamental understanding of particle size effects. The results will help optimize ink formulations when designing new ink materials for electrohydrodynamic inkjet printing.

The detailed characterisation of nanoparticles is a crucial point in their further application. Without knowledge about their sizes, composition and lengths of ligands nanoparticles could not be used effectively. For example without information about diameters engineers are not able to design jet which with high efficiency would spread nanoparticles on substrate during printing. Without knowledge about composition and length of the ligands it would be difficult to predict what temperature to use during sintering. To learn more about nanoparticles which we are using (commercially available ligand stabilised silver nanoparticles) we have decided to perform series of experiments in order to better understand their properties. We have concentrated here on analysis of AgNPs morphology using HRTEM, AFM, DLS and UV-Vis. Chemical composition was checked using XPS and EDX, and finally electronic structure was investigated using UPS and STS. The size distribution measured using all four techn...

Journal of Physics: Conference Series, 2019

This work is devoted to the sintering of silver nanoparticle arrays in the form of lines by the local treatment with laser radiation with wavelengths of 527, 1054 and 1064 nm in pulsed and continuous laser modes. The silver nanoparticle lines were formed by the dry aerosol printing, free from organic solvents and surfactants. To form the lines with a width of 25–300 μm and a thickness of 0.1–15 μm a focused stream of nanoparticles with an average size of about 60 nm was used. It is shown that when using continuous laser radiation with a wavelength of 1064 nm, the minimal specific resistance of silver nanoparticle lines was achieved 3 times higher than that for the bulk material was reached.

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.

Comptes Rendus Chimie, 2012

Applied Physics Letters, 2007

As a direct write technology, the electrohydrodynamic printing of silver nanoparticles by using a focused nanocolloid jet is introduced. In this letter, two categorized types of examples of two-dimensional patterning were printed by using the electrohydrodynamic printing method. A spiral-type inductor was printed to demonstrate the feasibility of the electrohydrodynamic printing as a fabrication process. The printed spiral inductor produced 9.45μH and exhibited approximately five times larger resistivity (9.5μΩcm) than that of bulk silver after the sintering process. Then, complex geometries having square- and round-shape patterns were also printed.

Nanotechnology, Science and Applications, 2016

Printed electronics will bring to the consumer level great breakthroughs and unique products in the near future, shifting the usual paradigm of electronic devices and circuit boards from hard boxes and rigid sheets into flexible thin layers and bringing disposable electronics, smart tags, and so on. The most promising tool to achieve the target depends upon the availability of nanotechnology-based functional inks. A certain delay in the innovation-transfer process to the market is now being observed. Nevertheless, the most widely diffused product, settled technology, and the highest sales volumes are related to the silver nanoparticle-based ink market, representing the best example of commercial nanotechnology today. This is a compact review on synthesis routes, main properties, and practical applications.

2020

Electrohydrodynamic (EHD) ink-jet printing has been actively researched as a means of refining ink-jet printing. Currently, most of the research on this topic has centralized on the development of the printing process and optimization, while few studies have focused on the relationships between printing materials properties and printed patterns performance. In this study, silver and tungsten-based particle-solvent dispersed inks were formulated capable of EHD printing. Several formulations were made to explore key variances in their performance. More generally, a methodology was developed to characterized and evaluate ink printability using materials properties. It identified a critical relationship between the formulation and fluid properties, which affects the printing results and functional performance. Also, particle size was studied and it was shown that it can drastically impact droplet image behaviors. In order to capture and analyze these phenomena, machine vision was utilized, assisting capture highspeed images to characterize droplet shape and timely response. In the silver-based ink formulation study, our data reveals that under identical printing conditions, the size of the printed features is a function of ink fluid viscosity, surface tension, and dielectric constant. Within the same formulation, the size of the printed features is a function of amplitude, frequency, and duty ratio of the alternating current (AC) square wave voltage signal. In our tungsten ink study, the droplet impact behaviors on glass substrates, including impact reaction time, droplet height, diameter, and dynamic contact angle, are functions of particle size of tungsten nanoparticle used in the ink formulation. With the discovery of relationships at hand, optimal formulations were proposed for inks used in the EHD printing regarding printing resolution and stabilization. The x-ray shielding efficiency was also evaluated on the differences between bulk tungsten and nanoparticle ink multilayer printed tungsten. Data suggested that with the increase of the numbers of layers printed, the shielding efficiency increases indicating an improved, denser nanoparticle packing condition. Finally, future research directions were proposed, including further improving printing resolution, improved nanoparticle packing density and 3D printability.

Japanese Journal of Applied Physics, 2015

Silver nanoparticles (AgNPs) were synthesized in aqueous solutions by reduction of silver nitrate (AgNO3) assisted by a helium dc microplasma jet at atmospheric pressure without additional chemical reducing agents. Surfactant-free AgNPs were obtained at low initial AgNO3 precursor concentrations ≤0.5 mM. A surface plasmon resonance peak at approximately 400 nm confirmed the presence of AgNPs. At higher concentrations, sucrose was used to prevent agglomeration and cap the growth of nanoparticles. The effects of the molar ratio of sucrose/AgNO3 on the size distribution and morphologies of AgNPs were investigated. The average sizes of AgNPs synthesized at molar ratios of 20, 50, and 60% were 11.2 ± 0.4, 10.0 ± 0.2, and 6.2 ± 0.1 nm, respectively.

Advanced Materials Research, 2008

Here we report the synthesis of nanoparticles with aspect ratios of up to five by synthesis in small concentrated volumes of reactants using an ink-jet printer. Silver and gold nanoparticles were synthesized rapidly on transparent sheets using a commercial ink jet printer. A commercial inkjet printer was modified by replacing conventional inks with different reactants including silver nitrate, ammonium-complex silver, gold chloride reduced by ascorbic acid. The reaction was allowed to occur directly on the substrate within a short reaction time and confined reaction volume defined by the droplet size on the substrate. The nanoparticles and microrods formed on the substrate depend on pH and ionic concentrations of the solutions. The pH of the solutions is an important factor controlling the aspect ratio of microrods. When the concentration of silver ions in the reactant solution was increased the number of particles deposited on the substrate increased subsequently. Anisotropic particles could be formed uniformly over very large area surfaces (1mm x 20mm). This method can be suitable for rapid synthesis of anisotropic particles for potential application in metal-enhanced fluorescence sensing, antibacterial coating, anti reflection coatings, amongst others.