Facile Preparation of Ultrasmall Void Metallic Nanogap from Self-Assembled Gold-Silica Core-Shell Nanoparticles Monolayer via Kinetic Control.

A facile preparation of ultrasmall 1-2 nm void metallic nanogaps on various solid substrates is proposed by utilizing the self-assembly of a uniform gold-silica core-shell nanoparticle monolayer at interfaces and chemical etching. The ultrasmall void metallic nanogap shows 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.