Gold mesoflower arrays with sub-10 nm intraparticle gaps for highly sensitive and repeatable surface enhanced Raman spectroscopy

Abstract

Self-assembling Au mesoflower arrays are prepared using a polymethylmethacrylate (PMMA) template on an iron substrate via a combined top-down/bottom-up nanofabrication strategy. The PMMA template with the holes around 300-500 nm in diameter is first fabricated by using polymer blend lithography on iron substrates, and the highly homogeneous Au mesoflower arrays with less than 10 nm intraparticle gaps are subsequently obtained by an in situ galvanic reaction between HAuCl4 solution and the iron substrate under optimal stirring of the solution as well as reaction time. Owing to the unique mesostructures and uniformity, Raman measurements show that the gold mesoflower arrays obtained demonstrated a strong and reproducible surface enhanced Raman scattering (SERS) enhancement on the order of ∼10(7)-10(8). The development of a SERS substrate based on the Au mesoflowers with high spatial density of hot spots, relatively low cost and facial synthesis provides a novel strategy for applications in chemical and biomolecular sensing.

Polymer blend lithography for metal films: large-area patterning with over 1 billion holes/inch2

“…The metal nano-disc arrays have a variety of potential applications such as the localized growth of ZnO nano wires or rods [31–32] or plasmonic applications [23]. The surface of the metal can be selectively modified with molecules such as thiols and used for immobilization of biomaterials [33].…”

“…Instead of silicon wafers, other materials such as glass or metal can also be used as substrates. For example iron was used as substrate for the fabrication of nanoporous gold mesoflower arrays, which served afterwards for surface-enhanced Raman scattering [23]. With the metal PBL technique it is possible to fabricate more than one billion metal islands or holes on a substrate with a size of 1 inch × 1 inch.…”

Particle‐Arrayed Silver Mesocubes Synthesized via Reducing Silver Oxide Mesocrystals for Surface‐Enhanced Raman Spectroscopy

“…Surface‐enhanced Raman scattering (SERS)‐based signal detection and molecular identification are new, powerful spectroscopy techniques attracting considerable interests in the fields of nanomaterials, biotechnologies, chemical analysis, and environmental monitoring . At present, the fabrication of SERS substrates with a stable, uniform, and high average enhancement factor over relatively large areas remains a great challenge . With the aim of creating a high amount of effective “hot spots” within individual particle, and simultaneously keeping high reliability and reproducibility, various metal particles with highly rough surfaces have been fabricated.…”

Reversible mechano-electrochemical writing of metallic nanostructures with the tip of an atomic force microscope

“…Atomic force microscopy (AFM) and related techniques are valuable tools for imaging surfaces and surface processes on the nanometer scale. Examples of recent work can be found in the literature [30–40]. At the same time, the scanning tips of the atomic force microscope, the scanning tunneling microscope (STM) and related instruments can be used as tools for surface modification and nanolithography [9–12 41–48], even down to the atomic scale [41–45].…”