Synthesis and formation mechanism of micron-size silver flakes with high radius-thickness ratio: application to silver paste

Abstract

Micron-size ultrathin silver flakes were synthesized via a simple and environmentally friendly approach. The microstructure of ultrathin silver flakes was determined by some dominant parameters, including the pH value of solution, the adding speed of silver nitrate, and the dosage of polyvinyl alcohol (PVA-124). The detailed characterization revealed that the as-synthesized silver flakes were typical 2–3 µm in diameter and 50–100 nm in thickness. And the flake-particle ratio was over 80%. Meanwhile, a possible formation mechanism of the silver flakes has been briefly discussed based upon the morphology evolution of silver flakes at different growth stages. Moreover, the ultrathin silver flakes conductive pastes dried at low temperature exhibited a good conductivity of 4.3 × 10−4 Ω·m even after 100 days, indicating their wide potential applications in the electronic materials.