Facile synthesis of micrometer-sized gold nanoplates through an aniline-assisted route in ethylene glycol solution

Micrometer-sized edge, polygonal gold plates of several 10 nm thickness, called gold nanoplates, have been synthesized in large quantities through simply introducing aniline to a heated ethylene glycol (EG) solution of hydrogen tetrachloroaurate (HAuCl4·4H2O) without any other capping agents or surfactants. Electron diffraction (ED) and X-ray diffraction (XRD) patterns identified the as-prepared gold nanoplates were single crystals bound primarily by {1 1 1} facets. The study of the optical properties showed these large gold nanoplates had strong absorption in near infrared region (NIR). Investigations suggested the amount of aniline added to the reaction solution played a key role in producing gold nanoplates and the size of the gold nanoplates can be tuned by adjusting the stirring speed. The possible formation mechanism of the as-prepared gold nanoplates was also discussed.