Manipulating the functionalization surface of graphene-encapsulated gold nanoparticles with single-walled carbon nanotubes for SERS sensing

Graphene-encapsulated gold nanoparticles (referred as graphene nanoparticles or GNPs) were recently reported as a potential plasmonic substrate for future bio-compatible devices, chemical sensors and many catalysis systems. However, the desired surface functionality creation of such GNPs is often limited by the insufficient surface area of the 2D graphene shell. In this paper, we report the design and realization of a novel bio-functionalization approach to covalently anchor singled-walled carbon nanotubes (SWCNTs) onto the GNP surface, rendering a unique nanocomposite architecture, namely GNP-CNT, with effectively increased surface functional sites. We found that the theoretical plasmonic "hot-spots" of our GNP-CNT nanoarchitectures were accumulated at the conjunction and interface sites of the GNP and SWCNTs. This further enables their advanced application as a substrate material for the surface-enhanced Raman spectroscopic (SERS) sensing. Experimentally we found that the GNP-CNT substrate exhibited nicely improved SERS performance as compared with the pristine GNP substrate. This paper paves a new bio-compatible avenue for design of future SERS sensing, bio-imaging and other bio-compatible materials. (C) 2018 Published by Elsevier Ltd.