Preparation and Characterization of Different Shapes of Silver Nanostructures in Aqueous Solution

We have developed a new and simple one-pot synthetic approach for the preparation of single-crystalline rose-, spike-, and snowflake-shaped silver nanostructures (NSs) in aqueous solution. We obtained these variously shaped Ag NSs by carefully controlling the nature and concentration of the stabilizers, which included sodium acetate, sodium citrate, and poly(ethylene glycol). To the best of our knowledge, this paper is the first to describe the preparation of roseshaped Ag NSs, also called Ag nanoflowers (NFs), through such a simple synthetic route. The thus-prepared Ag NFs exhibited a specific surface area of 15.6 m2 g-1, a contact angle of 97.6 ± 2.2°, high conductivity (1.97 × 106 S/cm), and efficient optothermal conversion efficiency (the temperature rose 23.03 ± 0.21 °C after laser irradiation at 808 nm for 3 min). The snowflake-shaped Ag NSs allowed the enhancement of Raman scattering (SERS) signals of rhodamine 6G by a factor of 2.4 × 106, leading to a detection limit of 10 nM.