(391g) Electrostatic Self-Assembly of Binary Nanocrystals with a Diamond-like Lattice

Grzybowski, B. A., Northwestern University
Kalsin, A. M., Northwestern University
Fialkowski, M., Northwestern University
Smoukov, S. K., North Carolina State University
Bishop, K. J. M., Penn State University
Paszewski, M., Northwestern University

Self-assembly of charged, equally sized metal nanoparticles of two types (gold and silver) leads to the formation of large, sphalerite (diamond-like) crystals, in which each nanoparticle has four oppositely charged neighbors. Formation of these non?close-packed structures is a consequence of electrostatic effects specific to the nanoscale, where the thickness of the screening layer is commensurate with the dimensions of the assembling objects. Because of electrostatic stabilization of larger crystallizing particles by smaller ones, better-quality crystals can be obtained from more polydisperse nanoparticle solutions.