Reduced Graphene Oxide–Silver Nanoparticle\nComposite as an Active SERS Material

Abstract

Selectivity and enhanced sensitivity\nfor SERS measurements are\nhighly desirable for environmental and analytical applications. Interaction\nof a target molecule with SERS substrate plays a pivotal role in determining\nthe magnitude of enhancement and spectral profile of the SERS signal.\nA reduced graphene oxide–Ag nanoparticle (RGO-Ag NP) composite\nhas been designed to boost SERRS sensitivity of a porphyrin derivative.\nComplexation between 5,10,15,20-tetrakis­(1-methyl-4-pyridinio)­porphyrin\ntetra­(<i>p</i>-toluenesulfonate) (TMPyP) porphyrin and the\nRGO-Ag NP composite is evidenced by a red-shifted porphyrin absorption\nband. Results indicate complexation is influential in improved surface-enhanced\nresonance Raman (SERRS) signal for TMPyP and thus offers an advantage\nfor target molecule detection at low concentration levels. The combined\neffects of RGO and Ag NPs in the enhancement of SERS signal of TMPyP\nare discussed.