Synthesis and characterization of silicon nanoclusters

Chapter 1 begins with an orientation to the relationships between size, molecular weight, molar amounts, surface area, and other physical aspects of silicon nanoclusters. A review of the current literature on nanoclusters focusing on silicon nanoclusters follows. The literature review is concluded with a discussion of the conditions that are favorable for the formation of nanoclusters.; Chapter 2 goes through the solution synthesis and characterization of nanocrystalline silicon terminated by n-alkyl groups. Using reactive Zintl salts nanocrystalline silicon particles were synthesized and characterized. They appear to be well terminated and stable.; Chapter 3 and 4 introduce and go over the multi-nuclear solid state nuclear magnetic resonance (NMR) characterization of silicon nanoclusters. A combination of 23Na, 29Si, and 13C magic angle spinning with and without cross polarization to 1H nuclei have been used to investigate the reaction of sodium silicide (NaSi) with silicon tetrachloride (SiCl₄) followed by varying degrees of surface passivation. Reaction with SiCl₄ produces an additional 29Si resonance that survives subsequent capping and oxidation reactions. Two surface passivated samples are reported here. The 29Si NMR spectrum corresponding to a sample incompletely passivated with butyl groups gives several peaks lying between −67 ppm and −81 ppm that can be attributed to surface silicon atoms. NMR spectra of both this sample and one corresponding to a completely butyl passivated nanocrystal suggest that terminal silicon sites in the incompletely passivated sample are modified by treatment with water.