Facile Preparation and Growth Mechanism of New-Type Gold Nanoplates

Abstract

When a sticky gel consisting of an aqueous HAuCl4 solution mixed with poly-vinylpyrrolidone (PVP) surfactant is kept at room temperature (about 30 °C), the HAuCl4 is reduced by the PVP, resulting in the formation of nanostructures. In this study, gold nanoplates with new shapes, which were single crystalline, several micrometers wide, and tens of nanometers thick, were mass-synthesized by adjusting the crystal growth conditions. For example, through inducing temperature decrease (10-20 °C) in the early stage of crystal growth, the product is dominated by star-like gold nanoplates, together with other new shapes such as shields, concave and convex triangles, corner snipped shapes, triple branched shapes, and shapes that are step-rich in the side plane. Based on theoretical calculations, we present the growth mechanism of these new gold nanoplates. Under certain growth conditions, the (111) plane of the gold crystal can grow not only along the direction into regular triangular or hexagonal nanoplates, but also along other directions such as and , to give new nanoplates with high-index side facets.