One-step synthesis of micro-sized flake silver particles as electrically conductive adhesive fillers in printed electronics

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) 2023, 121(0), , pp.77-91
• Main Authors: Lai, Yaobin, Zhu, Sitian, Li, Jian, Zhang, Hui, Qi, Tao
• Format: Article
• Language: English
• Subjects: Electrically conductive adhesive; Flake silver particles; Formation mechanism; Rare earth; Silver sheets; Thin film printed circuit; 화학공학
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2023.01.008

[Display omitted] •One-step synthesis of uniform micro-sized flake silver particles is achieved.•The cheaper La(OH)3 was used to replace other expensive agent (H2PtCl6 or H2PdCl4) as structure-directing agent.•The silver particles present smoother and straighter surface.•The bulk resistivity of ECAs filled by as-prepared silver particles (about 4.4 × 10-5 Ω·cm) is considerably lower than that filled by commercial silver particles (about 1.2 × 10-4 Ω·cm).•The formation mechanism of micro-sized flake silver particles was proposed. A novel one-step liquid phase reduction method was proposed to synthesize uniform micro-sized flake silver particles at room temperature. The La(OH)3 was used to replace other expensive agent (H2PtCl6 or H2PdCl4) as structure-directing agent. The role of the reagents and possible formation mechanism of micro-sized flake silver particles were investigated in detail. The effect of each synthesis parameter on morphology and particle size of micro-sized flake silver particles was also explored. It is found that La(OH)3 could control the reduction rate of Ag+ and its oriented growth by adsorbing on the (111) crystal plane of silver particles. The uniform micro-sized flake silver particles with a length of 4-55 μm and thickness of 0.2-5 μm could be synthesized by tuning the synthesis parameters. The synthesized micro-sized flake silver particles presented a smoother and straighter surface compared with commercial micro-sized flake silver particles prepared by ball milling. What is more important, the electrically conductive adhesive (ECA) filled by as-prepared micro-sized flake silver particles printed on polyethylene terephthalate film (PET) exhibited lower bulk resistivity (about 4.4×10-5 Ω·cm) than that filled by the commercial ball-milled micro-sized flake silver particles with the same Ag content of 80 wt. % (about 1.2×10-4 Ω·cm).