The strong dependence of the bi-functionalities of core–shell-like gold-based nanocomposites on the size of gold nanoparticles

Abstract

In this work, gold nanoparticles (AuNPs) of various sizes (Au_x, x = 32, 50, 68, 87 and 107 nm) were facially assembled with a glycine derivative (G₆) and graphene quantum dots (GQDs), respectively. Subsequently, novel core–shell-like Au_x/glycine derivative (G₆)/graphene quantum dot (GQD) composites were achieved, which showed a strong dependence of their fluorescence and surface enhanced Raman scattering (SERS) response on the size of the AuNPs. It was indicated that the energy transfer efficiency between the photoexcited GQDs and AuNPs was closely dependent on the size of the AuNPs. Also, according to the comparative SERS response of crystal violet (CV) on Au_x and Au_x/G₆/GQD substrates, it was demonstrated that the electromagnetic field of the AuNPs surface is also strongly dependent on the size of the AuNPs. Meanwhile, the synergetic effect between AuNPs and GQDs was helpful to control the SERS response of the Au_x/G₆/GQD substrate.