Well-defined assembly of plasmonic metal nanoparticles by dielectrophoresis for highly sensitive SERS-active substrates

Abstract

In this study, dielectrophoresis (DEP) was performed to develop highly sensitive surface- enhanced Raman scattering (SERS)-active substrates for molecular sensing. Substrates with a circular hole pattern were used, and plasmonic particles were trapped and immobilized along the edges of the pattern using dielectrophoretic forces. The arranged particles created hotspots, resulting in an enhanced SERS signal that was detectable even at concentrations as low as 10⁻¹⁰ M. This uniform arrangement provided a consistent signal over a large area. In addition, it was experimentally verified that the behavior of the particles varied with pattern diameter. This phenomenon was further supported by theoretical analysis. The proposed DEP-based SERS substrates are expected to be useful in various applications due to their excellent reproducibility and reliability.