Study On The Size-controlled Systhesis Of Silver Micro/nano-particles And Its Application In Conductive Ink

In recent years, as a driving force, the research on micro-nano science and technology has prompted development of industry. As a novel functional materials,silver micro/nano-materials is of great attention due to its excellent electrical, chemical and optical properties. Research show that its crystal structure, morphology, particle size,particle size distribution, dispersibility and other physical parameters are some of the key factors for its excellent performance and application. As a result, the size/morphology-controlled synthesis of silver micro/nano-particles has great theoretical and practical significance.Due to the development of morphology controllable synthesis of silver particles,the properties of silver particles, to some extent, can be well-controlled. Mastery over the size of the structure enables further control over its properties. Controlled synthesis of silver micro/nano-particles was investgated via the chemical route in the aqueous phase.In the preparation of nano silver particles, we followed some parameterize to fulfill those requirements, which include seed size and the quality of silver salt and seed.With polyvinyl pyrrolidone(PVP) used as the stabilizer and ascorbic acid as a reducing agent, the experiment adjusts the kinetics of reducing agent by changing the amount of sodium hydroxide. Silver chloride colloidcan was reduced to make seed of different grain sizes. And the seeds were added into the sub-micron silver powder reaction system, which plays an important role in allocating the newborn silver atoms in the process of nucleation and growth to achieve sub-micron particle size-controlled preparation of silver. The SEM show that silver particles with the diameters of 20 nm up to 100 nm were obtained by varying the the amount of sodium hydroxide while the diameters of 145 nm up to 315 nm were obtained by varying seed size and the amount of silver salt and seed.In the preparation of micron silver particles, we followed some parameterizes to model those requirements, which include silver dosage, pH and the amount of dispersant. Polyvinyl pyrrolidone(PVP) was used as the stabilizer, and ascorbic acid was applied as a reducing agent, in a 40 °C water bath, which reacting with silver nitrate to produce Spherical/ Quasi spherical sliver particles. By adjusting the parameters of theconditions, exploring the influence of particle size, and taking advantage of this law, we obtain a controlled particle size silver. The SEM show that particle size increases with increasing concentration of silver nitrate and the amount of dispersant.When increasing the difference between pH and isoelectric point(pH=4), the particle size decreases.Finally, by using the homemade micro/nano-particles mentioned above to prepare silver conductive ink, the preliminary study results show that the silver conductive ink conductivity meet the application requirements. The silver used in the printed circuit technology would be well applied in the future.