Nanostructured colloidal metal and semiconductor particles

摘要

Coloidal gold and silver are difficult to manipulate. The surfaces are normally coated with organic acids or polymers, and coventional methods for thin metal oxide coatings normally result in clumping and heterocoagulation. We have recently developed a method to silica-coat gold and silver particles which aviods any particle coalescence. The method can be applied to a wide range of nanoparitcles [1,2]. In this report we present some results from stuides into chemical reactions of nanosized coated metal particles using high resultion transmission elecron microscopy. THe chemical reactions were caried out on silical coated silver and gold nanoparticels in aqueous solution. The reaction of a single Ag SIO2 nanopaticle w ith I2 to form AgI was monitored directly by transmission electron microscopy. As well the dissolution of Au cores by cyanide ion led to the creation of monodisperse, holow, nanosized silica partices.