The purpose of this research project was to determine the feasibility of labelling a water-soluble polymer with a water-soluble dye and quencher. The water-soluble dye chosen was bis-(2,2-bipyridine)-ruthenium(II) -5-amino-1,10-phenanthroline hexafluorophosphate, RuNH2 , with a water solubility of 1×10^−3 mol/L. 3,5-Dinitrobenzyl alcohol was found to be an efficient quencher with a quenching rate constant of 2.7×10^9 M^−1 s^−1 as well as a water-solubility of 5×10^−3 mol/L. Both the dye and quencher were modified in a way such that they could be covalently linked to a polymer. RuNH2 was converted to bis-(2,2-bipyridine)-ruthenium(II)-5-isothiocyanato-1,10- phenanthroline hexafluoro-phosphate, RuNCS, using thiophosgene to yield an active isothiocyanate group. 3,5-Dinitrobenzylamine, DNB-NH2 , was synthesized via tritylamination of the commercially available 3,5-dinitrobenzyl chloride. A synthetic pathway has been established to covalently attach the dye and quencher to poly(N,N-dimethylacrylamide)(PDMA). Luminescence of this system was first characterized in N,N-dimethylformamide (DMF) rather than water to allow for future comparisons to be made between this water-soluble system and the previously established non-water-soluble system. Luminescence analysis of the RuNCS labelled polymers in DMF could be fitted with a sum of three exponentials with the strongest contribution being that of a 1000 ns long-lived species which is characteristic of the free dye. A luminescence decay of a polymer labelled with both RuNCS and DNB-NH2 was acquired and showed static quenching of the ruthenium dye by the quencher.

The purpose of this research project was to determine the feasibility of labelling a water-soluble polymer with a water-soluble dye and quencher. The water-soluble dye chosen was bis-(2,2-bipyridine)-ruthenium(II) -5-amino-1,10-phenanthroline hexafluorophosphate, RuNH2 , with a water solubility of 1×10^−3 mol/L. 3,5-Dinitrobenzyl alcohol was found to be an efficient quencher with a quenching rate constant of 2.7×10^9 M^−1 s^−1 as well as a water-solubility of 5×10^−3 mol/L. Both the dye and quencher were modified in a way such that they could be covalently linked to a polymer. RuNH2 was converted to bis-(2,2-bipyridine)-ruthenium(II)-5-isothiocyanato-1,10- phenanthroline hexafluoro-phosphate, RuNCS, using thiophosgene to yield an active isothiocyanate group. 3,5-Dinitrobenzylamine, DNB-NH2 , was synthesized via tritylamination of the commercially available 3,5-dinitrobenzyl chloride. A synthetic pathway has been established to covalently attach the dye and quencher to poly(N,N-dimethylacrylamide)(PDMA). Luminescence of this system was first characterized in N,N-dimethylformamide (DMF) rather than water to allow for future comparisons to be made between this water-soluble system and the previously established non-water-soluble system. Luminescence analysis of the RuNCS labelled polymers in DMF could be fitted with a sum of three exponentials with the strongest contribution being that of a 1000 ns long-lived species which is characteristic of the free dye. A luminescence decay of a polymer labelled with both RuNCS and DNB-NH2 was acquired and showed static quenching of the ruthenium dye by the quencher.

We have grown Ga1-xMnxN films on c-sapphire substrate by plasma-assisted MBE with different Mn fluxes. The films are characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), electron backscatter diffraction (EBSD), high¡Vresolution X-ray diffraction (HR-XRD), Raman scattering, photoluminescence (PL), cathodoluminescence (CL), transmission spectra, reflection spectra and X-ray photoelectron spectroscopy (XPS). The SEM images show films thickness between 550 to 850 nm and EBSD indicates samples normal direction is c-axis. EDS spectra show the Mn is present in GaMnN samples. According to XRD and Raman scattering, Mn element occupying Ga site on GaN and Mn-N clusters phase coexist on films. From transmission and reflection spectra, stronger absorption at about 1.5 eV and 1.8 eV to 3.4 eV absorption band are found. The PL and CL show GaN band gap at 3.4 eV and blue band from 2.4 eV to 3.3 eV maybe due to defect level. Finally, the XPS spectra indicate Mn acceptor level is contributed to Mn+2 or Mn+3 states.

Gamma-phase lithium aluminate (LiAlO2) single crystal is grown by Czochralski pulling method and a-plane LiAlO2(LAO) is chosen as the substrate for subsequent gallium nitride (GaN) epitaxial growth by plasma-assisted molecular beam epitaxy (PAMBE). The lattice mismatch between the nitride and the substrate is greatly reduced due to small lattice mismatch of~0.3% between [0001]GaN and [010]LAO and of~1.7% between [11-20]GaN and [001]LAO in the plane of the substrate LAO(100). Pure hexagonal [10-10]GaN is successfully grown directly on the LAO substrate without buffer layer. Crystal quality and properties are analyzed through a series of measurements, including reflection high-energy electron diffraction (RHEED), field-emission electron microscopy (FESEM), electron backscatter diffraction (EBSD), x-ray diffraction and cathodo luminescence (CL).

The powder phosphor of £]-LiGaO2¡GCe3+ ¡B£]-LiGaO2¡GEu3+ and £^-LiAlO2 were prepared by using the reagents of Ga2O3 (99.999%), Al2O3 (99.99¢H), Li2CO3 (99.999%), CeO2 (99.98%) and Eu2O3 (99.98%). Cerium and europium doped £]-LiGaO2 respectively and europium doped £^-LiAlO2 phosphors were synthesized by the method of high temperature solid-state reaction. The Ga, Al, Li, Ce and Eu reagents were mixed according to the requisite stoichiometric ratios. The mixture was mixed thoroughly and sintered at requisite temperature in a tube furnace in atmosphere for several hours. Then the products were cooled down to room temperature and ground into powder to get the final product. The phase purity and crystallinity of the as-synthesized, cerium and europium doped £]-LiGaO2 phosphors respectively and europium doped £^-LiAlO2 phosphors, were characterized using x-ray powder diffraction. The particle size and the morphology of the samples were analyzed by scanning electron microscopy. Luminescence properties of the £]-LiGaO2 and the £^-LiAlO2 phosphor samples with different cerium doping and europium doping concentrations were studied. The photoluminescence spectra of cerium doped £]-LiGaO2 showed a broad yellow-green light emission range from 450 to 640 nm with the peak at 519 nm. The strongest intensity peak of luminescence was found at 0.5 % cerium doping concentration synthesized at 1000¢J. The photoluminescence spectra of europium doped £]-LiGaO2 and £^-LiAlO2 showed the orange-red light emission range from 588 to 630 nm with the maximum peak at 612 nm. The strongest intensity peaks of luminescence were found respectively at 9 % and 7 % europium doping concentration synthesized at 1000¢J.

Thèse doctorat : Chimie : Strasbourg 1 : 2006. / Titre provenant de l'écran-titre. Notes bibliogr.

Thèse de doctorat : Chimie : Strasbourg : 2009. / Titre provenant de l'écran-titre. Notes bibliogr.. Index.

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xiii, 139 p. : ill. Vita. Includes abstract. Includes bibliographical references.

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