Fabrication of oxidation-resistant submicron copper particles and the conductive ink as well as its sintering behavior on the flexible substrate

摘要

The submicron copper particles with a mean diameter of 197 nm were obtained using lactic acid as stabilizer and sodium hypophosphite as a mild reducing agent. The obtained Cu particles show a good oxidation resistance owing to the weak reducibility of lactic acid. The screen printable copper ink with a metal loading of 50 wt.% was prepared using the obtained copper particles. The copper films after sintering at 150 °C for 1 h in nitrogen atmosphere exhibit a relatively low resistivity of 1.87 × 10⁻⁴Ω•m. The conductive copper film circuits were successfully fabricated on flexible polyimide (PI) substrate, with which an LED can be lighted up easily.