Fig. 6

Tunability of graphene-based plasmonic materials. a–c Electrical tunability of graphene/Au nanorod hybrid structure. a Schematic diagram of a graphene/Au nanorod hybrid structure gated through ionic liquid. A top electrolyte gate was used to control plasmon resonance of the hybrid system by varying optical transitions in graphene. b A high-resolution scanning electron micrograph (SEM) image of the graphene/single Au nanorod. Graphene draped over the nanorods (white arrow). c Rayleigh scattering spectra of the graphene/Au nanorod structure at 0.5, − 0.1, − 0.9, and − 1.5 V of gate voltage. The plasmon resonance shifted depending on the gate voltage. Reprinted with permission from [99]. Copyright 2012 American Chemical Society. d, e Structural tunability of AgNPs/graphene hybrid structure. AgNPs with d 49.3 nm and e 67.5 nm of lateral dimension on graphene formed through thermal annealing of 4 and 8 nm thick Ag films, respectively. f Transmittance spectra taken on graphene (black) and AgNPs/graphene hybrid structures (colored solid lines). SPR of AgNPs/graphene structures redshifts with increasing lateral size of the AgNPs. The 4, 8, and 14 nm AgNPs in label indicate the thickness of as-deposited Ag film which were transformed to AgNPs with 49.3, 67.5, and 147.5 nm of lateral size, respectively, after dewetting. Reproduced with permission from [103]. Copyright 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim