Surface analysis using shell-isolated nanoparticle-enhanced Raman spectroscopy

Abstract

Surface-enhanced Raman scattering (SERS) is a powerful fingerprint vibrational spectroscopy with a single-molecule detection limit, but its applications are generally restricted to 'free-electron-like' metal substrates such as Au, Ag and Cu nanostructures. We have invented a shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) technique, using Au-core silica-shell nanoparticles (Au@SiO(2) NPs), which makes SERS universally applicable to surfaces with any composition and any morphology. This protocol describes how to prepare shell-isolated nanoparticles (SHINs) with different well-controlled core sizes (55 and 120 nm), shapes (nanospheres, nanorods and nanocubes) and shell thicknesses (1-20 nm). It then describes how to apply SHINs to Pt and Au single-crystal surfaces with different facets in an electrochemical environment, on Si wafer surfaces adsorbed with hydrogen, on ZnO nanorods, and on living bacteria and fruit. With this method, SHINs can be prepared for use in ~3 h, and each subsequent procedure for SHINERS measurement requires 1-2 h.

Electrospray surface-enhanced Raman spectroscopy (ES-SERS) for probing surface chemical compositions of atmospherically relevant particles

“…Recent studies have introduced the use of core-shell composite gold nanoparticles to eliminate the chemical enhancement (Li et al, 2010(Li et al, , 2013. The outermost inert shell layer of the nanoparticle prevents its direct contact (i.e., coupling) with analyte molecules.…”

Advances in surface-enhanced vibrational spectroscopy at electrochemical interfaces

“…The technique, termed shell-isolated nanoparticle-enhanced Raman spectroscopy, or SHINERS, has dramatically expanded the practical application of SERS, enabling measurements on effectively any substrate due to the minimal interference of the 'SHIN' resonators [82][83][84]. Procedures to synthesise SHINs are now well-documented [85], typical particles comprising a 55-120 nm spherical gold or silver core [82,86,87] [92], graphene [93,94] and other carbon materials [95,96]. Example core-shell particles are depicted in Figure 5 The substrate generality of SHINERS has greatly benefitted electrochemical Raman spectroscopy and an impressive range of native electrode substrates have been investigated including Ag [97,98], Au [99][100][101][102][103][104], Pt [99,102], Pd [102], Rh [105], Ni alloys [106,107], Cu [108] and glassy carbon (GC) [102].…”

Shell‐Isolated Nanoparticle‐Enhanced Raman Spectroscopy (SHINERS)

“…This condition has severely limited the breadth of practical applications of SERS to other materials widely used in materials, energy, medical, and life sciences. Moreover, atomically flat surfaces of various single-crystals, which are commonly used in surface science and semiconductor technology, were almost excluded.To overcome these two problems several groups have developed a strategy of "borrowing SERS activity" to extend the SERS study to non-traditional SERS substrates [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. This approach employs the long-range effect of the enormous electromagnetic (EM) field created by the high SERS-active Au or Ag nanostructures nearby.…”