Copper–zinc particles with zinc-enriched surfaces generated via spray pyrolysis

Copper is an inexpensive replacement for silver in electronic applications such as solar cell metallization, electromagnetic interference packaging, and printable electronics. However, copper has a characteristically low reduction potential under ambient conditions, favoring formation of non-conducting copper oxides. Here, a spray pyrolysis method of producing oxidation resistant copper particles with surfaces rich in zinc, without need for post-fabrication modifications is described. The effects of precursor and reactor parameters on the particle surface composition with respect to the bulk composition are explored. At reactor temperature conditions of 1000 °C with a precursor containing 90 at% copper–10 at% zinc, the formation of desired morphologies was achieved, smooth dense particles with surfaces enriched in zinc. Increasing the concentration of zinc in the precursor did not improve enrichment, and instead led to the formation of a zinc diamine chloride [Zn(NH₃)₂Cl₂] byproduct.

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