Particles and inks and films using them
Particles and particle films are provided. In certain examples, particles produced from a single phase process may be used to provide industrial scale synthesis of particles for use in devices such as printed wiring boards.
1. A method of producing capped silver nanoparticles in a single phase solution, the method comprising:
mixing silver or a silver salt with a capping agent in a single phase solution comprising ethylene glycol, ethanol and toluene;
adding a hydrazine reducing agent to the single phase solution; and
isolating the capped silver nanoparticles from the single phase solution.
2. The method of claim 1 further comprising removing the capping agent from the capped metal particles to provide uncapped particles.
3. The method of claim 2 further comprising dispersing the uncapped particles in a solvent.
4. The method of claim 3 further comprising mixing the dispersed uncapped particles with an additional metal to provide an alloy.
5. The method of claim 4 in which the additional metal is one or more metals selected from the group consisting of gold, palladium, platinum, copper, and tin.
6. The method of claim 3 further comprising disposing the dispersed uncapped particles on a substrate.
7. The method of claim 6 in which the disposing step comprises spin coating, inkjet printing, paste printing or combinations thereof.
8. The method of claim 2 in which the step of removing the capping agent comprises dispersing the capped particles in a solvent and heating the dispersed capped particles.
9. The method of claim 1 further comprising selecting the capping agent to be hexadecylamine.
10. The method of claim 1 , further comprising adjusting relative amounts of one or more of the ethylene glycol, ethanol and toluene to achieve the single phase solution.
11. The method of claim 1 , further comprising washing the isolated capped silver nanoparticles.
12. The method of claim 1 , wherein an amount of the capping agent sufficient to provide at least about 2% by weight capping agent in the capped silver nanoparticles is present in the single phase solution.
13. The method of claim 12 , further comprising reducing the amount of capping agent in the capped silver nanoparticles to less than about 2% by weight capping agent.
14. The method of claim 12 , further comprising reducing the amount of capping agent in the capped silver nanoparticles to less than about 1% by weight capping agent.
15. The method of claim 12 , further comprising reducing the amount of capping agent in the capped silver nanoparticles to less than about 0.5% by weight capping agent.
16. The method of claim 12 , further comprising reducing the amount of capping agent in the capped silver nanoparticles to less than about 0.1% by weight capping agent.