Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.

Thesis (M.S.)--University of North Texas, Dec., 2007. / Title from title page display. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 67-73). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (p. 119-154).

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Th. univ.--Rennes 1, 1997. / En annexe, choix de textes en anglais. Bibliogr. p. 205-214. Résumé.

Made available in DSpace on 2014-06-11T19:23:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-16Bitstream added on 2014-06-13T19:29:33Z : No. of bitstreams: 1 ravaro_lp_me_bauru.pdf: 967737 bytes, checksum: 4467c85af230546c2464c3465069b809 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dióxido de estanho (Sn'O IND. 2') é um semicondutor do tipo n, que é transparente na região do ultravioleta/visível. Possui muitas aplicações como, por exemplo, eletrodos transparentes, sensores de gás, coletores solares e dispositivos eletro-ópticos. Quando dopado com íons terras-raras, Sn'O IND. 2' pode ser utilizado na confecção de dispositivos para comunicação óptica, principalmente na forma de filmes finos. Os íons terras-raras têm grande relevância devido às transições eletrônicas, que vão do ultravioleta ao infravermelho próximo. Outro aspecto importante está ligado às características físico-químicas da suspensão coloidal de onde são depositados os filmes. Filmes obtidos com pH elevado da suspensão apresentam alta resistividade elétrica e baixa cristalinidade em relação aos filmes obtidos com pHs das suspensões ácidas. O nível mais profundo de energia dos defeitos em Sn'O IND. 2' foi alterado da energia de 140eV até 67eV para variação do pHs 11, até 6, de acordo com a avaliação da energia de ativação. Os difratogramas destes filmes indicam aumento de cristalinidade com a diminuição do pH. Xerogéis de Sn'O IND. 2':Er2% com alteração do pH em relação a suspensão neutra apresentaram espectro de emissão mais intenso na região infravermelha para a amostra com pH7 e um pequeno alargamento dos picos de emissão para a amostra com pH4 e mais acentuado para a amostra com pH11, em bom acordo com medidas de Raman. Relatamos também a emissão na região visível de filme fino de Sn'O IND. 2' dopado com 'Er POT. 3+', que é um formato adequado da amostra para confecção de dispositivos. / Tin dioxide (Sn'O IND. 2') is an n-type oxide semicondutor, which is transparent in the ultraviolet/visible range. It presents many types of applications, such as transparent electrodes, gas sensors, solar collectors and eletro-optical devices. When doped with rare-earth ions, Sn'O IND. 2' may be used to make optical communication devies, in the thin film configuration. Rare-earth ions have great relevance due to their electronic transitions, covering from ultraviolet to near infrared. Another important characteristic is related to the physical-chemical properties of the starting colloidal suspension to deposit the films. Films obtained with high pH of the suspension presents high electric resistivity and low crystallinity compared to films obtained with acid pH. The deepest energy level of the defects in Sn'O IND. 2' has been changed from the energy of 140 eV to 67 e V when the pH changes from 11 to 6. Diffractograms of these films show increase in the crystallinity with pH decrease. Sn'O IND. 2':Er2% xerogels with modified pH show more intense emission spectra in the infrared for sample with pH 7 and a low broadening of emission peaks for the sample with pH 4 and moer intense for pH 11, suggesting an ideal pH for higher emission samples, in good agreement with Raman shift spectra. We also report emission in the visible range from of an 'Er POT. 3+' -doped thin film, which is a very convenient form for devices fabrication.

Orientador: Younes Messaddeq / Coorientador: Silvia Helena Santagneli / Coorientador: Denis Boudreau / Banca: Marcelo Nalin / Banca: Hellmut Eckert / Banca: Martin Bernier / Abstract: The development of new optical fibers capable to operate in the deep-ultraviolet (DUV, 200-300 nm) and the vacuum-ultraviolet (VUV, 120-200 nm) would benefit to laser technologies, microlithography techniques (increased spatial resolution) and elemental chemical sensing applications (phosphorous and sulfur sensing in agriculture). The only well-established UV-transmitting fiber existing to date consists in high- OH/fluorine doped silica glass core/clad fibers. However, the utilization of such fibers is limited by solarisation effect that degrades the UV-light transmission with long time exposition. Mixed fluoride-phosphate (FP) glasses with ultra-low content of impurities can be VUV- and/or DUV-transmitting materials, offering thus an alternative to the commercialized high-OH/fluorine doped silica fibers. These glasses are produced by mixing fluorides and polyphosphates to combine their properties as excellent glass-forming ability, low refractive index and broad optical transmission windows ranging from ~160 to 4000 nm. Also, when doped with trivalent rare-earth (RE) ions, the low phonon fluorine environment is favorable for RE high quantum efficiencies, making then suitable for photonic application in the form of fiber and/or bulk glass. Firstly, highly pure FP glasses were prepared and utilized to fabricate step-index optical fibers, by a modified crucible technique. In a first step, the bulk glasses were studied to be highly transparent in the VUV region, down to 160 nm, ... (Complete abstract click electronic access below) / Resumo: O desenvolvimento de novas fibras ópticas capazes de operar na região do ultravioleta profundo (200-300 nm) e de vácuo (120-200 nm) beneficiariam aplicações em tecnologias a laser, técnicas de microlitografia (maior resolução espacial) e detecção química elementar (detecção de fósforo e enxofre na agricultura). A única fibra de transmissão UV bem estabelecida existente até o momento consiste em fibras núcleo-casca de vidro de sílica dopado com OH/flúor. No entanto, a utilização de tais fibras é limitada pelo efeito de solarização que degrada a transmissão da luz UV apos exposição prolongada. Os vidros mistos fluoreto-fosfato com baixas quantidades de impurezas, são materiais transmissores de luz UV-profundo e vácuo, oferecendo assim uma alternativa frente as fibras de silica utilizadas hoje. Estes vidros são produzidos pela mistura de fluoretos e polifosfatos com propriedades combinadas de ambos como, excelente capacidade de formação vítrea, baixo índice de refração e ampla janela de transmissão (~ 160 a 4000 nm). Além disso, quando dopados com íons terras-raras trivalentes, o ambiente de baixa energia de fonon dos fluoretos é favorável para emissões dos TRs com alta eficiência quântica, tornando-os então adequados para aplicações na área da fotônica na forma de fibra e/ou bulk. Portanto, em primeiro lugar, foram preparados vidros FP altamente puros e utilizados para fabricação de fibras ópticas de índice-degrau, pela técnica do cadinho. Na primeira etapa, os vidros na forma ... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Orientador: Sidney José Lima Ribeiro / Banca: Marie-Joelle Menu / Banca: Lucas Alonso Rocha / Banca: Lauro June Queiroz Maia / Banca: Michel Wong Chi Man / Banca: Marc Verelst / Banca: Isabelle Gautier-Luneau / Resumo: The design of heterobimetallic luminescent complexes has gained growing interest in recent years due to their unique photophysical properties. More specifically, the development of heterobimetallic complexes using d-block chromophores to sensitize the near-infrared (NIR) emission of lanthanide complexes (such as Nd(III) and Yb(III)) has received significant attention taking into account their longer emission wavelengths and the interest of the NIR emission which penetrates human tissue more effectively than UV light. These properties give them potential applications in medical diagnostics or biomedical assays. Transitions to excited state levels of transition metal complexes occurring in the visible and characterized by large absorption coefficients, could efficiently sensitize f-f levels of Ln(III) ions. In this work new d-f heterobimetallic complexes containing silylated ligands were prepared supported on silica materials. [Ru(bpy)2(bpmd)]Cl2 (labeled Ru), [Ru(bpy)(bpy-Si)(bpmd)]Cl2 (labeled RuL) and [Ln(TTA-Si)3] (labeled LnL3) and d-f heterobimetallic complexes, Ru-LnL3 and Ln-RuL (Ln = Nd3+, Yb3+) were prepared. Structural characterization was carried out by Raman Scattering, 1H and 13C NMR spectroscopies. Results obtained from 1H-13C HMBC and HSQC correlation NMR spectra confirm the formation of proposed complexes. Photophysical properties studies highlight the efficiency of Ru-Ln energy transfer processes in NIR-emitting lanthanide complexes mediated by conjugated brid... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: ABSTRACT The design of heterobimetallic luminescent complexes has gained growing interest in recent years due to their unique photophysical properties. More specifically, the development of heterobimetallic complexes using d - block chromophores to sensitize the near - infrared (NIR) emission of lanthanide complexes (such as Nd(III) and Yb(III)) has received significant attention taking into account their longer emission wavelengths and the interest of the NIR emission which pene trates human tissue more effectively than UV light. These properties give them potential applications in medical diagnostics or biomedical assays. Transitions to excited state levels of transition metal complexes occurring in the visible and characterized by large absorption coefficients, could efficiently sensitize f - f levels of Ln(III) ions. I n this work new d - f heterobimetallic complexes containing silylated ligands were prepared supported on silica materials. [Ru(bpy) 2 (bpmd)]Cl 2 (labeled Ru ), [Ru(bpy)(bpy - Si)(bpmd)]Cl 2 (labeled RuL ) and [Ln(TTA - Si) 3 ] (labeled LnL3 ) and d - f heterobimetallic complexes, Ru - LnL3 and Ln - RuL (Ln = Nd 3+, Yb 3+ ) were prepared. Structural characterization was carried out by Raman Scattering, 1 H and 13 C NMR spectroscopies . Results obtained from 1 H - 13 C HMBC and HSQC correlation NMR spectra confirm the formation of proposed complexes. Photophysical properties studies highlight the efficiency of Ru - Ln energy transfer processes in NIR - emitting lanthanide complexes mediated by conjugated bridging ligand (2,2' - bipyrimidine). Lifetime measurements were carried out and values of quantum yield for energy transfer (  ET ) between 30 and 84 % could be evaluated.  ET of 7 3 .4 % obtained for the Yb - RuL complex is the largest value reported for Ru(II) - Yb(III) heterobimetallic complexes so far. Grafting on different silica matrix was also demonstrated... / Doutor

Title: Spectroscopic Study of Singlet Oxygen in Cells and Model Systems Author: Marek Scholz Department: Department of Chemical Physics and Optics Supervisor: doc. RNDr. Roman Dědic, Ph.D., KChFO Abstract: Singlet oxygen (1O2), the first excited state of molecular oxygen, plays many important roles in nature and technology. The work is aimed at development of novel methods for monitoring of 1O2 in cells and other biological samples. Two main ap- proaches were employed: direct detection of the very weak near-infrared phospho- rescence of 1O2, and detection of Singlet Oxygen-Feedback Delayed Fluorescence (SOFDF), which is the emission from the photosensitizer induced by energy transfer from 1O2. The first part of the thesis introduces the basic concepts of photophysics and photochemistry of 1O2: its generation, deactivation, applications, and overview of detection methods. The second part presents the experimental results. Wide-field mi- crospectroscopic detection of 1O2 phosphorescence enabled us to acquire 1O2-based images and near-infrared spectra from single cells incubated with photosensitizers. However, the direct detection suffers from the inherently very low phosphorescence quantum yield. It is shown that SOFDF may overcome this problem and become a promising alternative tool for studies of 1O2 and...