High-Throughput Synthesis of Uniform Silver Seed Particles by a Continuous Microfluidic Synthesis Platform

Abstract

Controlled silver particle geometries require at least a synthesis in two steps which strongly differ in their reaction kinetics. For the first step, the very fast seed formation, chaotic advection-based micromixers are tested in combination with a batch reactor for the growth step. Nanoparticles with narrow size distribution and excellent shape uniformity can be prepared in large batches. To achieve a highly reproducible and homogeneous particle solution, a microfluidic system containing three different micromixers for optimal mixing of the chemical precursors is established, allowing stringent control of every synthesis step. The produced silver particles can be used as seeds for forming anisotropic particles. Their further potential is demonstrated by preparation of anisotropic silver triangles. The thus generated seed particles are better suited for growing to triangles than those from conventional batch synthesis. The synthesis of silver nanoprisms is realized in a novel microfluidic platform consisting of three different micromixers. Uniform crystalline particles were prepared, acting as seed particles for a second batch reactor-based synthesis.