Plasmonic nanogap-enhanced Raman scattering has attracted considerable attention in the fields of Raman-based bioanalytical applications and materials science. Various strategies have been proposed to prepare nanostructures with an inter- or intra-nanogap for fundamental study models or applications. This report focuses on recent advances in synthetic methods to fabricate intra-nanogap structures with diverse dimensions, with detailed focus on the theory and bioanalytical applications. Synthetic strategies ranging from the use of a silica layer to small molecules, the use of polymers and galvanic replacement, are extensively investigated. Furthermore, various core structures, such as spherical, rod-, and cube-shaped, are widely studied, and greatly expand the diversity of plasmonic nanostructures with an intra-nanogap. Theoretical calculations, ranging from the first plasmonic hybridization model that is applied to a concentric Au–SiO2–Au nanosphere to the modern quantum corrected model, have evolved to accurately describe the plasmonic resonance property in concentric core–shell nanostructures with a subnanometer nanogap. The greatly enhanced and uniform Raman responses from the localized Raman reporter in the built-in nanogap have made it possible to achieve promising probes with an extraordinary high sensitivity in various formats, such as biomolecule detection, high-resolution cell imaging, and an in vivo imaging application.
Bibliographical noteFunding Information:
The authors acknowledge financial support from a Korea University Grant and from the KU‐KIST research fund. This research was also supported by the National Research Foundation of Korea (No. NRF‐2017M3D1A1039421 and 2018R1A2A3075499).
The authors acknowledge financial support from a Korea University Grant and from the KU-KIST research fund. This research was also supported by the National Research Foundation of Korea (No. NRF-2017M3D1A1039421 and 2018R1A2A3075499).
© 2020 Wiley-VCH GmbH
- intra-nanogap structures
- quantum tunneling
- small molecules
- surface-enhanced Raman scattering
ASJC Scopus subject areas
- General Materials Science
- Mechanics of Materials
- Mechanical Engineering