From Philadelphia, at a meeting of the American Chemical Society
Scientists have created a new type of quantum dot that could find applications in everything from biological imaging to computer displays. Like their semiconductor counterparts (SN: 2/15/03, p. 107: NanoLights! Camera! Action!), these tiny clusters of gold atoms fluoresce brightly and emit different wavelengths of light when scientists vary the number of atoms in each cluster.
Robert Dickson and his colleagues at the Georgia Institute of Technology in Atlanta created the clusters by dissolving gold salts in a solution containing branched-polymer molecules called dendrimers. The dendrimers encapsulated the gold atoms, creating the nanometer-scale quantum dots.
By varying the concentration of the gold relative to the dendrimers, the researchers produced dots of many sizes, each of which fluoresces at a different wavelength. For instance, 5-atom dots emit ultraviolet l