SCI-BYTES - WHAT'S NEW IN RESEARCH

Week of February 10, 2008

Hot Paper in Chemistry

"Structural diversity in binary nanoparticle superlattices," by Elena V. Shevchenko, Dmitri V. Talapin, Nicholas A. Kotov, Stephen O'Brien, and Christopher B. Murray, Nature, 439(7072): 55-9, 5 January 2006.

[Authors' affiliations: IBM Research Division, Yorktown Heights, NY; Columbia University, New York, NY; University of Michigan, Ann Arbor]

Abstract: "Assembly of small building blocks such as atoms, molecules, and nanoparticles into macroscopic structures--that is, 'bottom up' assembly--is a theme that runs through chemistry, biology and material science. Bacteria, macromolecules, and nanoparticles can self-assemble, generating ordered structures with a precision that challenges current lithographic techniques. The assembly of nanoparticles of two different materials into a binary nanoparticle superlattice (BNSL) can provide a general and inexpensive path to a large variety of materials (metamaterials) with precisely controlled chemical composition and tight placement of the components. Maximization of the nanoparticle packing density has been proposed as the driving force for BNSL formation, and only a few BNSL structures have been predicted to be thermodynamically stable. Recently, colloidal crystals with micrometre-scale lattice spacings have been grown from oppositely charged polymethyl methacrylate spheres. Here we demonstrate formation of more than 15 different BNSL structures, using combinations of semiconducting, metallic and magnetic nanoparticle building blocks. At least ten of these colloidal crystalline structures have not been reported previously. We demonstrate that electrical charges on sterically stabilized nanoparticles determine BNSL stoichiometry; additional contributions from entropic, van der Waals, steric and dipolar forces stabilize the variety of BNSL structures."

This 2006 report from Nature was cited 24 times in current journal articles indexed by Thomson Scientific during September-October 2007. During that two-month period, only one other chemistry paper published in the last two years (excluding reviews) attracted a higher number of citations. Prior to the most recent bimonthly count, citations to the paper have accrued as follows:

July-August 2007: 12 citations
May-June 2007: 8
March-April 2007: 11
January-February 2007: 9
November-December 2006: 5
September-October 2006: 11
July-August 2006: 10
May-June 2006: 6
March-April 2006: 5
January-February 2006: 2

Total citations to date: 103

SOURCE: Hot Papers Database (Included with a subscription to the print newsletter Science Watch^®, available from the Research Services Group of Thomson Scientific. Packaged on a CD that is mailed with each Science Watch issue, the Hot Papers Database contains data on hundreds of highly cited papers published during the last two years. User interface permits searching by author, organization, journal, field, and more. Total citations, as well as citations accrued during successive bimonthly periods, can be assessed and graphed. An updated CD containing the most recent bimonthly data is mailed with every new issue of Science Watch, six times a year. The CD also includes an electronic version of the Science Watch issue in HTML format, for personal desktop access.