Figure 6. Optical applications of metal nanoisland-graphene composites.

(a) Use of the composition and geometric pattern of metal to selectively dope the underlying graphene with incident light, using localized surface plasmons. Further modification of individual nanoparticle geometries allows additional control over the electron transport properties (b). (a) and (b) reprinted with permission from reference²⁶. Copyright © 2012, American Chemical Society. Metal nanoislands on graphene have been used extensively as surface-enhanced Raman scattering (SERS) substrates with numerous applications such as structural strain mapping and time-dependent biological strain detection (c–g). (c–g) Reprinted and adapted with permission from reference⁷ and the Royal Society of Chemistry. A silver nanoisland on graphene substrate on bent glass is depicted (c) with the SERS mapped area marked by the narrow yellow box and the apex of the bent glass marked by the white dashed line. The strain gradient of the bent glass is detectable by SERS intensity attenuation (d), which results from nanoislands being pulled apart; polarization angle provides additional data on the direction of strain. Silver nanoisland on graphene substrates have been used for the simultaneous stimulation and detection of musculoskeletal cell (C2C12 myoblast) contractions through SERS (e). A fluorescence image of C2C12 cells on the silver nanoisland substrate is depicted (f) with nuclei (blue), actin (green), and myosin heavy chain (red) shown. Cell contractions were stimulated by applying a voltage across the conductive silver nanoisland substrate and detected using attenuations in the SERS signal (g).