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

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 lm and thick-ness of 0.2-5 lm 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 adhe-sive (ECA) filled by as-prepared micro-sized flake silver particles printed on polyethylene terephthalate film (PET) exhibited lower bulk resistivity (about 4.4x10-5 S2 center dot cm) than that filled by the commercial ball-milled micro-sized flake silver particles with the same Ag content of 80 wt. % (about 1.2x10-4 S2 center dot cm). CO 2023 Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engineering Chem-istry.

Automated summary

A novel one-step liquid phase reduction method using La(OH)3 as structure-directing agent was proposed to synthesize uniform micro-sized flake silver particles at room temperature. The effect of reagents and synthesis parameters on the morphology and particle size of the silver particles was investigated. The synthesized micro-sized flake silver particles showed improved surface properties and were more conductive compared to commercially prepared ball-milled silver particles. (Rating: 9 out of 10)