title: Highly fluorescent noble-metal quantum dots.
abstract: Highly fluorescent, water-soluble, few-atom noble-metal quantum dots have been created that behave as multielectron artificial atoms with discrete, size-tunable electronic transitions throughout the visible and near infrared. These molecular metals exhibit highly polarizable transitions and scale in size according to the simple relation E(Fermi)/N(1/3), predicted by the free-electron model of metallic behavior. This simple scaling indicates that fluorescence arises from intraband transitions of free electrons, and these conduction-electron transitions are the low-number limit of the plasmon-the collective dipole oscillations occurring when a continuous density of states is reached. Providing the missing link between atomic and nanoparticle behavior in noble metals, these emissive, water-soluble Au nanoclusters open new opportunities for biological labels, energy-transfer pairs, and light-emitting sources in nanoscale optoelectronics.
authors.affiliation: School of Chemistry and Biochemistry, and The Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA. jiezheng@fas.harvard.edu
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: Philip R
authors.initials: PR
authors.lastname: Nicovich
authors.forename: Robert M
authors.initials: RM
authors.lastname: Dickson
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry; D010777:Photochemistry; D045663:Quantum Dots
chemical_list: D005456:Fluorescent Dyes; D008670:Metals