La connaissance approfondie sur la luminescence des dispositifs photovoltaïques (PV) en a fait un outil de caractérisation puissant qui capte l'intérêt de la recherche et des industries du PV. Dans cette thèse, nous nous concentrons sur la luminescence des cellules solaires photovoltaïques à base de Cu(In,Ga)Se2. En particulier, nous explorons et revisitons ses dépendances temporelles, spectrales et spatiales. Cela a abouti dans un premier temps à la mise au point de nouvelles méthodes de caractérisation basée sur la luminescence de cette technologie PV en particulier. Nous montrons d’abord que par l’intermédiaire d'une méthode sans contact toute optique, nous sommes en mesure de détecter et de localiser les métastabilités de cette technologie. En utilisant une approche numérique basée sur des résultats expérimentaux de photoluminescence résolue en temps (TRPL) nous avions réussi à quantifier la densité des défauts de piégeage qui sont derrière ces métastabilités. Une fois quantifiée, nous traduisons cette densité en pertes absolues de performance PV de la cellule solaire. Ensuite, en explorant la dépendance spatiale de la luminescence des cellules solaires à base de Cu(In,Ga)Se2, nous avions corrélé avec succès, ses aspects temporels et spectrales en se basant sur la microscopie confocale à balayage et l’imagerie hyperspectrale. Cela nous a permis de généraliser nos résultats précédents à l'échelle globale des cellules solaires. Cette partie de la thèse nous a aidés à mieux comprendre une des origines fondamentales derrière l’inhomogénéité spatiale de la luminescence de ce type de dispositifs photovoltaïques.La dernière partie de la thèse était essentiellement technique et exploratoire. En particulier, nous introduisons une nouvelle technique optique dans le domaine de la caractérisation des dispositifs PV. Cette technique est dédiée à l’imagerie résolue en temps du temps de vie de fluorescence (TR-FLIM). Le principe de cette technique consiste essentiellement en acquisition d'images de luminescence du dispositif PV qui sont résolues temporellement. Avec ce nouveau dispositif expérimental, nous sommes maintenant en mesure de résoudre spatialement, et en temps réel la dynamique des porteurs de charge d'une technologie photovoltaïque donnée et accéder à ses propriétés électroniques clés. Une première démonstration a été faite sur une cellule solaire à base de GaAs, et pour laquelle nous avions extrait optiquement, la longueur de diffusion, la mobilité et le temps de vie de ses porteurs. De plus, nous avions pu estimer le coefficient de diffusion du matériau et son taux de dopage. / The extensive knowledge on the luminescence of photovoltaic (PV) devices has made it a powerful characterization tool that captures the interest of both research and industrial PV communities. In this thesis, we focus on the luminescence of Cu(In,Ga)Se2-based solar PV. In particular, we explore and revisit the luminescence temporal, spectral and spatial dependencies. This resulted in the development of new luminescence-based characterization methods for this particular PV technology. We show initially that by means of an all-optical, contactless methodology, we are able to detect and localize the metastabilities of this technology. Using a numerical approach based on experimental time-resolved photoluminescence (TRPL) we managed to quantify the trapping defects that are behind these metastabilities. Once quantified, we translated it into absolute losses in the PV performance of the solar cell. By exploring the spatial dependence of the luminescence of Cu(In,Ga)Se2 solar cells, we successfully correlated its temporal and spectral aspects based on scanning confocal microscopy and hyperspectral imaging. This allowed us to generalize our previous findings at the global solar cell scale. This part of the thesis helped us better understand one of the fundamental origins behind the spatially inhomogeneous luminescence of Cu(In,Ga)Se2 PV devices. The final part of the thesis was mainly technical and exploratory. In particular, we introduced a new optical technique to the field of PV characterization. It is dedicated to time-resolved fluorescence lifetime imaging (TR-FLIM) which basically consists of acquiring time-resolved luminescence images of the PV device. With this new setup we are now able to spatially resolve, in real-time the charge carrier dynamics of a given PV technology and access its key electronic properties. A first application was made on a GaAs-based solar cell, for which we were able to optically extract the mobility, diffusion length and lifetime of its carriers. Finally, we were also able to estimate the diffusion coefficient of the material and its doping density.

Les orthophosphates de lanthanides dopés avec des Terres Rares (TR) (LnPO4) sont considérés comme des luminophores intéressants pour des applications optiques. Les luminophores sont des matériaux luminescents qui transforment certains types d'énergie (rayons X, ultraviolet, visible, infrarouge) principalement en lumière visible. Dans le cadre de cette thèse, les matrices YPO4 (orthophosphate d'yttrium), LuPO4 (orthophosphate de lutétium), GdPO4 (orthophosphate de gadolinium) et GdxY1-xPO4 (orthophosphate d'yttrium et gadolinium), dopées avec les ions Eu3+ (europium), Ce3+, Tb3+ (terbium), Er3+ (erbium), Tm3+ (thulium) et / ou Yb3+ (ytterbium) ont été synthétisés par procédé solvothermal. En jouant sur les conditions de synthèse, la phase cristalline, la taille et la morphologie des particules obtenues ont pu être contrôlées. Les échantillons ont été caractérisés par diffraction des rayons X (DRX), spectroscopie infrarouge de Transformée de Fourier, analyse thermogravimétrique (TG), spectroscopie Raman, microscopie électronique à balayage (MEB), microscopie électronique à transmission (MET), et spectroscopie de luminescence (spectres d’émission, d’excitation, rendements quantiques et déclins de fluorescence). En particulier, des nanofils et des nanoparticules de GdPO4:Eu3+, GdPO4:Tb3+ ont été élaborés, ainsi que des poudres de YPO4:Tb3+ avec des phases monoclinique, hexagonale ou quadratique. Il a été mis en évidence une influence significative de la structure cristalline et de la morphologie des luminophores sur leurs propriétés optiques. Des poudres avec une morphologie différente ont été utilisés comme charges pour la préparation de films composites polymère/luminophores. En jouant sur la formulation des orthophosphates et la nature des ions dopants, des luminophores fournissant une lumière proche du blanc idéal sous excitation UV ont pu être élaborés. L’ensemble de ce travail montre clairement les potentialités d’applications de ces matériaux dans des dispositifs basés sur une source d’excitation plasma ou sur la technologie des diodes électroluminescentes. / Rare earth (Re) doped lanthanide orthophosphates (LnPO4) are considered like promising phosphors for optical applications. Phosphors are luminescent materials which convert certain types of energy (X-ray, ultraviolet, visible, infrared) mainly into visible light. In this research Eu3+ (europium), Ce3+ (cerium), Tb3+ (terbium), Er3+ (erbium), Tm3+ (thulium) and/or Yb3+ (ytterbium) doped LuPO4 (lutetium orthophosphate), YPO4 (yttrium orthophosphate), GdPO4 (gadolinium orthophosphate) and/or GdxY1-xPO4 (yttrium-gadolinium orthophosphate) were synthesized by solvothermal process. By varying the synthesis conditions, the crystalline phase, particle size and morphology were controlled by the synthesis conditions these parameters affect the photoluminescent properties. The samples were characterized by means of X-ray Diffraction (XRD), Fourier transform Infrared (FT-IR), Thermogravimetric Analysis (TGA), Raman Spectroscopy, Scanning Electronic Microscopy (SEM), Transmission Electronic Microscopy (TEM) and photoluminescence spectroscopy (emission and excitation spectra, quantum yields and fluorescence decay times). In particular, nanowires and nanoparticles nanowires and nanoparticles of GdPO4:Eu3+, GdPO4:Tb3+ have been developed, as well as powders of YPO4:Tb3+ powders with monoclinic, hexagonal or tetragonal phases. It has been demonstrated a significant influence of the crystalline structure and morphology phosphors on their optical properties. Powders with different morphology were used as fillers for preparing luminescent composite polymer/phosphors films. By adjusting the orthophosphates formulation and dopant nature of ions, phosphors providing near perfect white light under UV excitation could be obtained. All of this work clearly shows the potential applications of these materials in devices based on a plasma excitation source or light emitting diode technology.

The reaction of the chelating ligand 4-[4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl]-N,N-diethyl-benzenamine, L, with pentacarbonylchlororhenium by conventional heating method produces the complexes fac-[ReL(CO)3Cl2] and fac-[Re2L(CO)6Cl2] in a period of 48 hours. The use of microwaves as the source of heat and the increase in the equivalents of one of the reactants leads to a more selective reaction and also decreases the reaction time to 1 hour. After proper purification, the photophysical properties of fac-[ReL(CO)3Cl] were analyzed. The solid-state photoluminescence analysis showed an emission band at 628 nm independent of temperature. However, in the solution studies, the emission band shifted from 550 nm in frozen media to 610 nm when the matrix became fluid. These results confirm that this complex possess a phenomenon known as rigidochromism.

L'imagerie par résonance magnétique est une des méthodes de diagnostic les plus utilisées, aussi bien dans le domaine médical que dans les études précliniques. Cependant, la relaxivité des agents de contraste commerciaux ne représente qu'une fraction de la relaxivité prédite par la théorie et il est nécessaire d'optimiser les différents paramètres dont elle dépend pour atteindre des valeurs de relaxivité plus élevées : nombre de molécules d'eau en première sphère de coordination, vitesse d'échange de l'eau, dynamique de rotation du complexe, relaxation électronique, distance Gd(III)-proton. Dans ce travail, nous présentons la synthèse, la stabilité et la relaxivité des complexes de Gd(III) de deux séries de ligands tripodes dérivés de la 8-hydroxyquinoléine, basés l'une sur une plateforme 1,4,7 triazacyclononane, l'autre sur un pivot azote central. Ces complexes ont montré des stabilités comparables à celles des agents commerciaux, des valeurs de relaxivités élevées dans l'eau ainsi qu'en milieu biologique. L'utilisation de la 8-hydroxyquinoléine comme base des ligands a permis de sensibiliser le Nd(III) et l'Yb(III) pour la luminescence proche infrarouge, ouvrant la possibilité pour le développement de nouveaux systèmes bimodaux. / Magnetic resonance imaging is a commonly used diagnostic method in medicinal practice as well as in biological and preclinical research. However, the relaxivity of commercial contrast agents is only a few percent of the theoretically predicted relaxivity. An optimisation of the different parameters who have an impact on the relaxivity (number of gadolinium bound water molecules, water exchange rate, rotation dynamic of the complex, electronic relaxation, Gd(III)-proton distance) is needed to obtain higher relaxivities. In this work, we present the synthesis, the stability and the relaxivity of the Gd(III) complexes of two series of 8-hydroxyquinolinate-based ligands, one using a 1,4,7 triazacyclononane platform, the other one using a central nitrogen architecture. Theses complexes show stabilities comparable to commercial agents, and high relaxivities in both water and serum. The 8-hydroxyquinolinate moiety allows these ligands to sensitize Nd(III) and Yb(III) for Near Infra Red (NIR) luminescence, leading to a new class of potential bimodal systems.

No description available.

The complex hydroclimatic response of the Upper Colorado River Basin (UCRB) to climate circulation patterns and their descriptive indices creates significant challenges to water managers, especially given the uncertain future of the climate. This dissertation addresses fundamental questions that surround extreme flooding in the UCRB by combining paleoflood field techniques, two analytical geochronology techniques and several numerical climate data analysis techniques. The three manuscripts included in this dissertation focus on the Dolores River Basin (DRB), a sub-basin within the UCRB in order to answer theoretical questions about the timing and climate patterns associated with extreme floods.It has become widely accepted that extreme flooding in the Lower Colorado River Basin (LCRB) is linked to a period when the frequency and intensity of El Nino periods was higher. Within the UCRB, and more specifically, the DRB, the linkages are less clear. The paleoflood chronology that we developed indicates that the peak episodes of flooding in the DRB occurred between roughly 300 A.D. and 1200 A.D. This period of flooding is out of phase with many floods in the LCRB, whose peak floods dominantly clustered in the last 700 years; a period of time coincident with the termination of large floods in the DRB. The chronology that I developed utilizes accelerator mass spectrometry radiocarbon (AMS 14C) and optically stimulated luminescence (OSL) to provide a detailed flood history, highlighting the importance of utilizing independent age control. Alternative, or less accurate chronologies would have resulted had we used AMS 14C or OSL alone, suggesting that some previously studied basins may have incorrect chronologies. The detailed flood chronology of this study has subsequently allowed us to contextualize extreme floods relative to middle--late Holocene climate variability.In an effort to provide a hydroclimatic context for flooding in the DRB, numerical analyses were applied to contemporary climate and streamflow data in order to identify the possible mechanisms that modulate precipitation and streamflow in the Western U.S. and more specifically, the DRB. Results from these techniques indicate that the DRB maintains a complex response to a major North Pacific, low-frequency circulation pattern. The North Pacific circulation modulates the low-frequency component of the DRB's precipitation and flooding, although the high frequency modulation remains very poorly characterized.

No description available.

Cyclodextrins, a family of compounds formed from a cyclic array of glucose monomers, contain a hydrophobic cavity which displays selective complexation of size specific guests. This selective molecular recognition is critical to the development of successful chemosensors. A selection of cyclodextrin-conjugates have been designed to report complexation of guests into the cyclodextrin cavity by optical and electrochemical means. Alkylated cyclodextrins containing a single linker group have been synthesised allowing the development of two cyclen-appended cyclodextrin conjugates and their lanthanide complexes. The tetraamide ligand (25) displayed a high rigidity, assessed by (^1)H NMR and luminescence methods. The Tb complex of the monoamide ligand [Tb.26] displayed long lived luminescence arising from energy transfer from cyclodextrin-complexed napthalene to the lanthanide. The association constant, K(_11), between naphthalene and the cyclodextrin [Tb.26], was calculated as 10,200 M(^-1). K(_11) between the Gd complex [Gd.26] and GdDOTAPh (40) was determined to be 1740M(^-1) by NMRD. These association constants are ca 14 and 7 times greater respectively than for the corresponding complexes with β-cyclodextrin (1). Bromonaphthalenes exhibit long lived phosphorescence when complexed within cyclodextrins. Four bromonaphthalene-appended cyclodextrins (57-60) were designed to form inframolecular self-complexes. Competitive complexation of optically transparent guests was expected to reduce the lifetime of phosphorescent emission. The four conjugates were successfully synthesised, although luminescence studies revealed no evidence for complex formation and no response upon competitive guest complexation was observed. The rotaxane (95) and corresponding thread (92) of a hydrophilic ferrocene- cyclodextrin conjugate were made and structurally assessed by CD, (^-1)H NMR and MALDI-TOF MS. The hydrophilic per-O-ethyl conjugates (93 & 100) were also synthesised. A lipophilic quinoline-cyclodextrin conjugate (94) was made, which, when incorporated into an optode membrane, allowed the detection of acetylcholine at micromolar concentrations.

Les complexes luminescents d'ions lanthanides(III), de par leurs caractéristiques spectroscopiques, sont des alternatives intéressantes aux fluorophores organiques usuels pour des applications dans le domaine de la bioanalyse et de l'imagerie cellulaire. Les propriétés photophysiques de ces types de complexes sont notamment exploitées en tant que donneur de FRET en temps résolu permettant d'améliorer la sensibilité et la spécificité de la détection. Des développements récents ont aussi permis d'obtenir des sondes luminescentes pour le pH physiologique, pour divers analytes endogènes ou pour des compartiments cellulaires. Dans ce cadre, l'enjeu est d'obtenir des luminophores plus brillants pour une détection plus performante. Pour ceci, nous avons souhaité, par deux approches, apporter des modifications à une plateforme nonacoordinante pyridinophane présentant trois antennes pyridine et possédant trois bras acétate. D'une part, les bras complexants ont été diversifiés soit par d'autres motifs monodentes, soit par des motifs potentiellement bidentes, de manière à protéger l'ion lanthanide de la coordination de toute molécule d'eau qui limiterait l'efficacité de luminescence. La mesure des propriétés photophysiques des complexes d'europium ou de terbium a montré que l'introduction d'un bras coordinant phosphonate permettait de diminuer le degré d'hydratation des complexes, et que, par ailleurs, l'introduction d'un bras coordinant picolinate, portant la coordinance du ligand à 10, conduisait à des complexes exempts d'eau. D'autre part, il a été envisagé de modifier les chromophores pyridine de manière à rapprocher la longueur d'onde du maximum d'absorption de la fenêtre de transparence des milieux biologiques, et à augmenter le coefficient d'absorption molaire de l'édifice. Sur la base de travaux précédents, le motif chlorine a été choisi, synthétisé, et fonctionnalisé en vue de son couplage à un des noyaux pyridine du macrocycle pyridinophane. / Lanthanide luminescent complexes are, through their spectroscopic properties, interesting alternatives to organic fluorophores for bioanalyses or cell imaging. Their photophysical properties are in particular used as time-resolved FRET donors that can improve the detection sensitivity and specificity. Recent developments afforded luminescent probes for physiological pH, several endogenous ions or for cell compartments. In this context, developing brighter luminophores is a major stake for a more efficient detection. Following this goal, we envisioned two approaches in order to modify a nonacoordinated pyridinophane platform bearing three pyridine antennae and three acetate pendant arms. First, the pendant arms have been modified, either by other monodentate moieties or by potentially bidentate moieties, in order to shield the lanthanide ion from any water molecule that could limit the luminescence efficiency. Europium or terbium complexes photophysical measurements showed that the introduction of a phosphonate coordinating arm decreased the number of coordinated water molecules, and that the introduction of a picolinate arm, leading to a decacoordinated ligand, afforded a water-free complex. Second, the pyridine chromophores were targeted both in order to bring the maximum absorption wavelength closer to the biological tissue transparency window and to increase the absorption coefficient of the structure. According to previous results (Borbas group), a chlorin antenna has been chosen, synthesized, and functionalized in order to couple this antenna to the pyridinophane macrocycle.

Orientador: Marian Rosaly Davolos / Coorientador: Marco Aurélio Cebim / Banca: Ieda Lúcia Viana Rosa / Banca: Rogéria Rocha Gonçalves / Resumo: As propriedades luminescentes, assim como a luminescência com excitação por raios X (XEOL) dos compostos Ba1-xEuxWO4, Ba1-3xEu2xWO4 e Ba1-2xEuxLixWO4 foram comparadas. As amostras foram obtidas pelo método Pechini com diferentes concentrações de dopante, diferentes atmosferas (mistura verde, argônio ou estática de ar) e temperaturas de tratamento térmico das amostras. BaWO4 forma compostos de estrutura tetragonal tipo Scheelita pertencentes ao grupo espacial I41/a. A substituição de íons Ba2+ por íons Eu3+ fornece dados importantes sobre a estrutura e a microssimetria do íon lantanídeo na matriz. Uma alternativa de compensação de carga com a introdução de Eu3+ no retículo do BaWO4 é a codopagem Li+/Eu3+. Neste sistema, dois cátions Ba2+ são substituídos, gerando a compensação de carga, resultando em propriedades luminescentes únicas. As amostras BaWO4, Ba1-xEuxWO4, Ba1-3xEu2xWO4 e Ba1-2xEuxLixWO4 (x = 1, 3 e 5% em mol) foram tratadas termicamente a 700, 900 e 1100º C e caracterizadas pelas técnicas de difração de raios X (XRD), espectroscopia de espalhamento Raman (RAMAN), espectroscopia vibracional de absorção na região do infravermelho (FTIR), microscopia eletrônica de varredura (SEM), índice de cor (CIE-Lab), espectroscopia de reflectância difusa (DRS), espectroscopia de fotoluminescência (PL), espectroscopia de luminescência com excitação por raios X (XEOL). As medidas XEOL foram realizadas no Instituto de Química Campus Araraquara. Todas as amostras apresentaram o mesmo perfil de difração, independentemente da concentração de dopante (máximo de 10%, Eu3+,Li+). A fase Scheelita (JCPDS-PDF nº 43-646) foi constatada. As exceções são as amostras BaWO4:Eu3+,Li+ dopadas com 1:1 e 3:3%, tratadas a 700 e 900 °C, que possuem baixa cristalinidade... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Luminescent properties, including X-ray excited optical luminescence (XEOL) of compounds Ba1-xEuxWO4, Ba1-3xEu2xWO4 and Ba1-2xEuxLixWO4 were compared. Samples were prepared by the Pechini method according to different dopand concentrations, different atmosphere (green mixture, argon and static air) and temperature during the thermal treatment of samples. Scheelite tetragonal structures of BaWO4 belongs to the space group I41/a. The Eu3+ substitutes for Ba2+ ions can provide important data on the structure and micro symmetry of lanthanide ions in the host lattice. An alternative way to charge compensation with the introduction of Eu3+ in the BaWO4 lattice is the co-doping with Li+ / Eu3+. In this system two Ba2+ cations were replaced, resulting in different luminescent properties. Samples of BaWO4, Ba1- xEuxWO4, Ba1-3xEu2xWO4 and Ba1-2xEuxLixWO4 ( x = 1, 3 and 5 mol%) and BaWO4: Eu3+, Li+ (1:1, 3:3, 5:5 mol%) were thermally treated at 700, 900 and 1100 °C and characterized by X-ray diffraction (XRD), Raman scattering vibrational spectroscopy (RAMAN), infrared absorption vibrational spectroscopy of (FTIR), scanning electron microscopy (SEM), color index, UV-Vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), X-ray excited optical luminescence (XEOL). All samples showed the same X-ray diffraction profile, independently of the dopants concentration (maximum of 10 at.%, Eu3+ + Li+) where it was observed the BaWO4 scheelite phase (JCPDS-PDF nº 43-646). The exceptions are the samples BaWO4:Eu3+,Li+ with 1,0:1,0 at.% and 3.0:3.0 at.%, treated at 700 and 900 °C, which presented low crystallinity. Greater crystallite size is achieved with smallest dopant concentration and highest thermal treatment temperature (700 to 1100 ºC). The study of the optical properties of Ba1-xEuxWO4, Ba1-3xEu2xWO4 e Ba1-2xEuxLixWO4 indicated that in... (Complete abstract click electronic access below) / Mestre