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Mohammad Mohammadi1 Shailesh Konda1 Shikuan Shao1 Santosh Gunturi1 Raymond Buchner1 Mark Swihart1

1, University at Buffalo SUNY, Buffalo, New York, United States

Metal nanomaterials have a variety of useful chemical, optical, catalytic, and electrical properties. Among them, silver nanomaterials are widely used today for printed electronics due to their high conductivity. However, silver is a relatively expensive material. To reduce costs, alloying silver with other conductive metals is beneficial. In this work, we have synthesized different multicomponent metal nanopowders and nano-inks including copper-silver and copper-nickel using the High Temperature Reducing Jet (HTRJ) process. The (HTRJ) reactor has been developed in our group to enable continuous one-step gas-phase (aerosol) synthesis of alloy metal nanoparticles from metal salt precursors. In this process, a fuel-rich hydrogen flame passes through a converging-diverging nozzle. An aqueous metal precursor solution injected at the throat section of the nozzle is atomized by the high velocity gas stream. The resulting droplets evaporate and the precursor decomposes, initiating nucleation of particles in a reducing environment containing excess H2. After the reaction zone, particles are cooled immediately to prevent further particle growth and coalescence. Recently, we have expanded the capabilities of this system to enable in situ functionalization of the synthesized bare nanopowders with organic ligands. In the first demonstration of this approach, we atomize short-chain amine molecules that bind to metal nanoparticles and deliver them at the reactor exit, where they evaporate. This initiates the gas-surface reaction between the ligands and nanoparticles. The resulting nanopowders are readily dispersed in organic non-polar solvents to make stable, uniform nano-inks. These stable nano-inks can be used as conductive inks for printed electronics applications or in many other applications where a stable metal nanoparticle dispersion is needed for low-cost processing.

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