KINETICALLY CONTROLLED SEEDED GROWTH SYNTHESIS OF UNIFORM GOLD NANOPARTICLES WITH DIAMETERS OF 15w-200 NM

Abstract

This paper presents a new seeded growth method to synthesize gold nanoparticles. Monodisperse gold nanoparticles with a narrow size distribution, a uniform quasi-spherical shape and controlled size from 15nm up to 200 nm were prepared by a kinetic process controlling seeded growth in the gold plating solutions (GPS) and using formaldehyde (HCHO) as a reducing reagent. Gold seeds are gold colloids (∼15 nm, ∼5.10¹¹ NPs/mL) with negatively charged citrate ions synthesized by the reduction of tetrachloroauric acid with trisodium citrate dihydrate in Milli-Q water.  In this process, the gold nanoparticles don’t have surfactant that advantages in biological application. The optical properties of the gold NPs have been tested by means of UV–Vis spectroscopy and morphology of them have been examined by transmission electron microscopy. Mechanism of seeded development is also clearly explained by examining over time the seeded growth in the different pH gold plating solutions (GPS) and in one step of the growth.