2-DIMENSIONAL ARRAYS OF COLLOIDAL GOLD PARTICLES - A FLEXIBLE APPROACH TO MACROSCOPIC METAL-SURFACES

Covalent attachment of nanometer-scale colloidal Au particles to organ osilane-coated substrates is a flexible and general approach to format ion of macroscopic Au surfaces that have well-defined nanostructure. V ariations in substrate (glass, metal, Al2O3), geometry (planar, cylind rical), functional group (-SH, -P(C6H5)(2), -NH2, -CN), and particle d iameter (2.5-120 nm) demonstrate that each component of these assembli es can be changed without adverse consequences. Information about part icle coverage and interparticle spacing has been obtained using atomic force microscopy, field emission scanning electron microscopy, and qu artz crystal microgravimetry. Bulk surface properties have been probed with UV-vis spectroscopy, cyclic voltammetry, and surface enhanced Ra man scattering. Successful application of the latter two techniques in dicates that these substrates may have value for Raman and electrochem ical measurements. The assembly method described herein is compared wi th previous methods for controlling the nanoscale roughness of metal s urfaces, and its potential applicability to the assembly of other coll oidal materials is discussed.