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Gratton, E. Eckhoff, Dean Alan 2012-10-12T18:12:16Z 2012-10-12T18:12:16Z 10000-01-01 2006-10 The primary theme of this dissertation is to characterize the optical and chemical properties of ultrasmall (~1 nm) silicon nanoparticles (Si-np) in aqueous environments, focusing on their potential for use as luminescent markers in biophysical and biological applications. Two systems are presented in detail: (1) Chapters 2-4 cover hydrogen-terminated Si-np that are prepared through electrochemical dispersion of a crystalline Si wafer and (2) Chapters 5-6 discuss carboxyl-functionalized Si-np prepared via thermal hydrosilylation of surface Si-H bonds with an ω-ester 1-alkene. Figure 1.1 shows a sketch (based on our results) of an ultrasmall Si-np that is ~1 nm in diameter and contains approximately thirty silicon atoms. The chemical groups shown on the surface are the different types of species that are discussed in this work: (a) hydrogen-terminated Si-np, (b) carboxyl-functionalized Si-np, and (c) various oxidized structures. Chemical and physical characterizations are done using nuclear magnetic resonance (1H-NMR), size exclusion chromatography (SEC), and infrared spectroscopy (FTIR). Optical characterization is done via absorption and steady-state photoluminescence (PL) and using capillary electrophoresis (CE) coupled with laser-induced fluorescence (LIF) detection. The instrumentation and experimental procedures are summarized in Chapter 8. Submitted by Meng Tao (mengtao2@illinois.edu) on 2012-10-12T18:12:16Z No. of bitstreams: 1 Eckhoff_Dean.pdf: 2542406 bytes, checksum: 4e78dac6592ff80c0fbc345880b529a3 (MD5) Made available in DSpace on 2012-10-12T18:12:16Z (GMT). No. of bitstreams: 1 Eckhoff_Dean.pdf: 2542406 bytes, checksum: 4e78dac6592ff80c0fbc345880b529a3 (MD5) Previous issue date: 2006-10 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Meng Tao (mengtao2@illinois.edu) on 2012-10-12T18:12:16Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:10:57-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Post 1923. No authorization form. Post 1923. No authorization form. U of I Only 5639954 http://hdl.handle.net/2142/34721 en ©2006 Dean Alan Eckhoff Hydrogen-terminated Si-np Carboxyl-functionalized Si-np Optical Characterization of Ultrasmall, Hydrogen-Terminated and Carboxyl-Functionalized Silicon Nanoparticles in Aqueous Environments Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.