Shape-Controlled Synthesis of Metal Nanostructures: The Case of Silver

• Published in: Chemistry : a European journal Vol. 11; no. 2; pp. 454 - 463
• Main Authors: Wiley, Benjamin, Sun, Yugang, Mayers, Brian, Xia, Younan
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 07-01-2005; WILEY‐VCH Verlag
• Subjects: Citrates - chemistry; Crystallization; Metals - chemistry; Nanostructures; polymers; shape-controlled synthesis; silver; Silver - chemistry
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200400927

The concept of shape‐controlled synthesis is discussed by investigating the growth mechanisms for silver nanocubes, nanowires, and nanospheres produced through a polymer‐mediated polyol process. Experimental parameters, such as the concentration of AgNO3 (the precursor to silver), the molar ratio between poly(vinylpyrrolidone) (PVP, the capping agent) and AgNO3, and the strength of chemical interaction between PVP and various crystallographic planes of silver, were found to determine the crystallinity of seeds (e.g., single crystal versus decahedral multiply twinned particles). In turn, the crystallinity of a seed and the extent of the PVP coverage on the seed were both instrumental in controlling the morphology of final product. The ability to generate silver nanostructures with well‐defined morphologies provides a great opportunity to experimentally and systematically study the relationship between their properties and geometric shapes.
Its all in the shape: Silver nanocubes, nanowires, and nanospheres (see figure for TEM images) have been synthesized through a polymer‐mediated polyol process. The concentrations of both silver precursor and polymer, as well as facet‐selective coverage of the polymer, played a role in the production of each morphology. Shape‐control of metal nanoparticles provides another tool (in addition to size) to tune their properties.