Size-Controlled Synthesis of Machinable Single Crystalline Gold Nanoplates

Monodispersive size-controlled gold nanoplates were synthesized with high purity from the reduction of hydrogen tetrachloroaurate by reduced amount of sodium citrate, which kinetically controls the reaction pathway, in the presence of poly(vinyl pyrrolidone) (PVP). With the insufficient addition of the reductant, the molar ratio of sodium citrate and PVP relative to hydrogen tetrachloroaurate played an important role in determining the geometric shape and size of the product. These nanoplates were single crystals with planar width of 80−500 nm and thickness of 10−40 nm, exhibiting strong surface plasmon absorption in the near-infrared (NIR) region of 700−2000 nm. The gold nanoplates were used as the synthetically provided nanoblocks to fabricate single-crystalline nanocomponents, such as a nanoscaled gear or a nanoscaled letter.