Metallic Nanogaps: Facile Preparation of Ultrasmall Void Metallic Nanogap from Self‐Assembled Gold–Silica Core–Shell Nanoparticles Monolayer via Kinetic Control (Adv. Mater. 29/2015)

Abstract

Ultrasmall void metallic nanogaps offer key advantages, such as a strong near‐field enhancement and free diffusion of analytes to the gap, which are useful in molecular sensing and monitoring. On page 4344, T. Kang and co‐workers report the facile preparation of high‐density, ultra‐small 1–2 nm void metallic nanogaps on various solid substrates by utilizing the self‐assembly of a uniform gold–silica core–shell nanoparticle monolayer at interfaces along with chemical etching.

Self-assembly of plasmonic nanostructures into superlattices for surface-enhanced Raman scattering applications

“…Compared with the liquideliquid assembly associated with the addition of a water immiscible organic phase, which can contaminate the Au NP surface and occupy interstices, liquideair is more simple and effective. Therefore, many interesting examples of NPs assembled at this region into SERS substrates have been reported [28,43,58]. LangmuireBlodgett (LB) technology is the most effective and widely used strategy for the assembly of NPs at the air/ water interface [64,65].…”

“…To this end, thin layers of SiO 2 have also been utilized to stabilize Au NPs after self-assembly at the airewater interface and transfer onto the support material, where the SiO 2 layer can be easily removed by chemical etching. More importantly, after removal of the protective layer, the strong Van der Waals attractions drive shortening of interparticle distance to 1e2 nm nanogaps [43], resulting in an additional 10 3 e10 4 increase in SERS EF.…”