Facile synthesis of labile gold nanodiscs by the Turkevich method

Abstract

The Turkevich method has been the preferred one for synthesis of gold nanoparticles (AuNPs), owing to its apparent simplicity and facility of replacing the citrate ions on the particle surface by molecules exhibiting different functionalities. Using the most common procedure labile spherical nanoparticles are usually obtained by this method. Here, by using factorial design of experiments, we demonstrated that gold nanodiscs (AuNDs) with short aspect ratio can be generated by the Turkevich method when Au:citrate ratio is 1:1. In comparison with the CTAB capped gold nanorods (AuNR), the citrate stabilized AuNDs exhibited a more labile character, allowing fast ligand exchange reactions and easy functionalization of the nanoparticle surface. In the presence of 4-mercaptopyridine (4-mpy), the surface enhancement Raman scattering effect was 100 and 1000 times higher than the one observed for CTAB-AuNR and spherical AuNPs, respectively, increasing the 4-mpy detection limit to 2.5 × 10−9 molL−1.