Plasmonic Core–Shell Nanomaterials and their Applications in Spectroscopies

Plasmonic core–shell nanostructures have attracted considerable attention in the scientific community recently due to their highly tunable optical properties. Plasmon‐enhanced spectroscopies are one of the main applications of plasmonic nanomaterials. When excited by an incident laser of suitable wavelength, strong and highly localized electromagnetic (EM) fields are generated around plasmonic nanomaterials, which can significantly boost excitation and/or radiation processes that amplify Raman, fluorescence, or nonlinear signals and improve spectroscopic sensitivity. Herein, recent developments in plasmon‐enhanced spectroscopies utilizing core–shell nanostructures are reviewed, including shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS), plasmon‐enhanced fluorescence spectroscopy, and plasmon‐enhanced nonlinear spectroscopy. The highly localized and strong electromagnetic fields generated by plasmonic nanomaterials, when excited by incident lasers with suitable wavelengths, can greatly boost the excitation and/or radiation processes of various spectroscopies, including Raman, fluorescence, or nonlinear spectroscopies, giving enhanced signals and improved spectral sensitivity.