Water-based carbon-coated copper nanoparticle fluid: Formation of conductive layers at low temperature by spin coating and inkjet deposition

A conductive inkjettable fluid was formulated based on carbon-coated copper nanoparticles. The copper particles were produced by vapor-phase reduction of copper chloride and coated in situ with carbon. The average particle size was 44-88 nm depending on the chosen production parameters. The optimized fluid was a water/ethylene glycol monobutyl ether/n-propanol mixture with 25 wt% nanoparticles, stabilized by a polymeric dispersing agent. A conductivity of 6.4 S/m was obtained with a single deposited layer without sintering or high-temperature annealing. The materials are interesting for several applications such as antistatic coatings, resistors, and sensors.