LIQUID-CHROMATOGRAPHIC ANALYSIS AND CHARACTERIZATION OF INORGANIC NANOCLUSTERS

We describe the application of the techniques of high pressure liquid chromatography (HPLC) to analyze and characterize various types of ino rganic nanoclusters. Both metal and semiconductor nanoclusters were gr own in inverse micelles and we demonstrate how the nanoclusters can be separated from the surfactants and other byproducts of the reaction b y using a variety of HPLC columns. We also discuss passivation of the cluster surface to prevent aggregation. The HPLC columns separate the clusters based upon a combination of size exclusion and chemical affin ity mechanisms and the optical properties of the purified clusters are determined on-line using a variety of detectors. These include a phot odiode array for collecting absorbance spectra, a fluorescence detecto r to monitor luminesence, and a conductivity detector to monitor surfa ce charge on the nanoclusters. We illustrate the analysis of nanoclust ers using HPLC by showing data from semiconductor Si, MoS2 nanocluster s and Au nanoclusters. An extremely novel luminesence was observed fro m very small metal nanoclusters. (C) 1997 Acta Metallurgica Inc.