Printed Electronic Nano-metals And Their Oxides, Synthesis And Characterization,

Printed electronics is a new kind of green industry, and it refers to the various features of ink, through a suitable printing technology, printed on various substrates to form a large area, flexible, low-cost electronic products and devices. The key point of printed electronics is to develop a variety of functional inks. In the PCB industry, the nano metal ink has been applied to ink-jet-printing of conductive pattern. The nano-silver conductive ink has been commercialized. Nano-copper conductive ink which easily be oxidized, is currently under worldwide development. This subject followed the world trend and aims to develop low-cost technology of preparation nano-metals.Firstly, copper nanoparticles used for conductive ink were synthesized using a relatively high-concentration (0.1 M), short reactive time (no more than 5 minutes) process which used double protective agents to obtain stable and homogeneous colloid. Cu nanoparticles had a diameter between 10nm～80nm by varying the amount of CTAB, PVP, reducing agent or reaction temperature, separately. The nano copper colloid was purified through electrodialysis, avoiding centrifugation and re-dispersion process in order to prevent oxidation and agglomeration. Transmission electron microscopy (TEM) images revealed the size and distribution of the synthesized nanoparticles, the X-ray analysis confirmed the formation of metallic copper and the element analysis suggested the high rate of purity of the Cu nanoparticles colloid.Secondly, highly monodispersed cuprous oxide (Cu2O) nanoparticles were successfully synthesized by a simple wet-chemical route and were characterized by XRD, HRTEM, UV-vis, and FTIR. The results showed that the size was controlled by varying the concentration of stabilizing molecule—oleic acid. Cu2O nanoparticles exhibit spherical shape with 2nm from HRTEM analysis and face-centered cubic (FCC) crystal structure when the molar ratio of oleic acid to copper precursor is 2. It can be concluded that the Cu2O nanoparticles were capped by oleic acid and polyethylene glycol monododecyl ether from FTIR. The nano-agglomeration can be filtrated and easily re-dispersed in apolar solvent without ultrasonic method or vigorous stirring.Thirdly, a simple large-scale water-based preparation method of nano-silver solution was created. Through chemical reduction method with silver nitrate as raw materials, lauric acid and ammonia as the protective agent, potassium borohydride as reducing agent, we prepared nano-particle size of about 10nm silver in aqueous solution. We explore the how the quantity of lauric acid to impact of the nano-silver particle size and morphology. Through acetone precipitation, nano silver can be centrifuged to enrichment, and then to form a nano-silver water-based ink.Finally, a new massive oil-soluble nano-silver preparation method was invented. By reacting in the mixed solvent, the oleic acid was coated on the surface of nano-silver, which has a diameter of only 3-5nm with a very uniform dispersion. In this manner, the soft-agglomeration of nano-silver can also be collected by filtration. This is a fundamental solution to the preparation of nano-silver large-scale production and high efficiency.In summary, this topic has developed four large-scale nano metal and metal oxide preparation methods of printed electronics and explores and studies the various experiment conditions on the impact of the product. These results are expected to impact the next preparation of nano-conductive ink.