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Beauvais, Jacques. "Gain optique dans le cadmium indium sulfide." Thesis, University of Ottawa (Canada), 1987. http://hdl.handle.net/10393/5316.
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So, David. "Copper indium sulfide colloidal quantum dot solar cells." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/404049.
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The ubiquity of solar energy conversion technology is an exciting target which we aspire for in this century. Colloidal quantum dot (CQD) solar cells are an attractive platform, being low-cost and allowing facile control on film properties and device fabrication, but to date are dominated by PbS but contains the restricted element Pb. CuInS2 (CIS) is a non-toxic alternative, showing promise in the bulk and as sensitizer but has not been thoroughly investigated for solid-state CQD solar cells. In this work we aim to incorporate
CIS nanocrystals (NCs) into the gamut of CQD solar cell materials by making optoelectronic CQD solids, by fabricating functional devices in various architectures and by identifying and overcoming the limiting material properties and device mechanisms.
We described a synthethic scheme that resulted in CIS NCs that can be deposited as CQD solids with controllable thicknesses. CIS NCs are typically synthesized using long chain thiols which are difficult to remove from the NC surface. We introduced long chain amines and phosphines, decomposable chalcogenides and zinc oleate treatments to substitute the functions that the thiol performed. This led to cubic nanocrystals with controllable size, from 2 nm to 3.2 nm, and optical properties with bandgaps ranging from 2.5 eV to 1.5 eV. These particles are also copper poor, decorated with indium and zinc on the surface. With this, we were able to design a ligand exchange protocol using hard
ligands for making solid-state CQD films which is a step forward to engineering optoelectronic devices.
We fabricated optoelectronic devices using these films and identified thin film properties that could limit device performance. These assemblies of CIS NCs couple to each other as seen in changes in photoluminescence lifetimes with distance. When the distance between nanocrystals is reduced, these p-type films conduct although having low mobilities (~10-5 cm2V-1s-1), displaying features that signify high trap densities, such as high responsivity and long photoconductive decays. The ability to form solid-state films has allowed us to fabricate optoelectronic devices such as transistors, photodetectors and solar cells. In solar cells, CIS CQD solids have led to good open-circuit volages
(VOCs), around 0.6 V, but low short-circuit currents (JSCs), ~1 mA/cm2, and fill factors (FFs), ~0.30. With the absorption coefficient of the CIS CQD solids, we found that the internal quantum efficiency (IQE) of these devices, is far below 10%. These highlight the importance of addressing the high trap density in the quantum dot solid.
We addressed the low JSCs and FFs in CIS CQD solar cells by utilizing a bulk heterojunction (BHJ) architecture. This non-annealed architecture was fabricated by increasing the pore size of the TiO2 network which allowed for the uniform and deep infiltration of CIS NCs. By using a BHJ architecture, we improved the performance of CIS CQD solar cells: mainly from an increase in JSC and FF leading to a six-fold increase in efficiency from initially at 0.15% to 1.16%. From analysis of Suns-Voc, -Jsc and transient Voc and Jsc measurements, we have identified that BHJ devices have less trap-assisted recombination and a lower activation energy (EU) for hole extraction. This was confirmed by shifts in the full device photoluminescence. We suggested that the BHJ structure allows for quenching of deeper tail states near the valence band in CIS by the transfer
of electrons from TiO2.
In this work, we have started from synthetic molecular precursors, to engineering supramolecular structures in trying to introduce CIS NCs into CQD optoelectronics, showcasing various devices: field effect transistors, photodetectors, bilayer and BHJ solar cells. In each stage, we have highlighted material, film and device properties which will be necessary for good performance. Ultimately this work aims to stimulate new interest in further development of CIS CQD solar cells, opening the possibility for non-toxic CQD photovoltaicsConseguir la ubicuidad de la tecnología de conversión de energía solar es un objetivo al que aspiramos en este siglo. Las células solares de puntos cuánticos coloidales (CQD) constituyen una plataforma interesante, debido a su bajo coste y a que permiten un control sencillo sobre las propiedades de la película y la fabricación de dispositivos, pero que están dominadas por PbS. El CuInS2 (CIS) es una alternativa no tóxica, prometedora en cuanto al grosor y como sensibilizadora, pero que no ha sido estudiada a fondo para su uso en células solares de CQD. El objetivo de este trabajo es incorporar nanocristales de CIS en toda la gama de materiales de células solares de CQD, mediante la creación de sólidos optoelectrónicos de CQD, fabricando dispositivos funcionales con diversas arquitecturas e identificando y superando las limitaciones de las propiedades de los materiales y los mecanismos de los dispositivos. Describimos una estrategia sintética que resultó en nanocristales de CIS que pueden ser depositados en forma de sólidos de CQD con espesores controlables. Los nanocristales de CIS son típicamente sintetizados utilizando tioles de cadena larga que son difíciles de eliminar de su superficie. Introdujimos aminas y fosfinas de cadena larga, un calcogenuro descomponible y tratamientos de oleato de zinc para substituir las funciones que realizaba el tiol. Esto generó nanocristales cúbicos de tamaño controlable, de 2 nm a 3.2 nm, con Eg de entre 2.5 eV y 1.5 eV. Estás partículas también son pobres en cobre, y su superficie está cubierta de indio y zinc. Mediante este proceso hemos podido diseñar un protocolo de intercambio de ligandos utilizando ácidos duros para generar películas de CQD en estado sólido, lo que constituye un avance para la ingeniería de dispositvos optoelectrónicos. Utilizando estas películas, fabricamos dispositivos optoelectrónicos e identificamos las propiedades de película fina que podrían limitar el rendimiento del dispositivo. Estos ensamblados de nanocristales de CIS se acoplan entre sí tal y como muestran los cambios en la duración de la fotoluminiscencia con la distancia. Cuando la distancia entre nanocristales se reduce, estas películas de tipo-p conducen, a pesar de tener bajas movilidades (~10-5 cm2V-1s-1) y de mostrar características que indican altas densidades de trampa, tales como una alta capacidad de respuesta y largos decaimientos fotoconductores. La capacidad para formar películas en estado sólido nos ha permitido fabricar dispositivos optoelectrónicos como transistores, fotodetectores y células solares. En las células solares, los sólidos de CQD de CIS han dado buenos Vocs, en torno a 0.6 V, pero bajas Jscs ~1 mA/cm2, y FFs ~0.30. Los coeficientes de absorción de los sólidos de CQDs de CIS indicaron que la eficiencia quántica interna (IQE) de estos dispositivos está muy por debajo del 10%. Esto destaca la importancia de solucionar la alta densidad de trampas en los sólidos de punto cuántico. Los bajos Jsc y FF en células solares de CQD de CIS fueron abordados utilizando una arquitectura de heterounión mayor (BHJ). Esta arquitectura no recocida se fabricó aumentando el tamaño de poro de la red de TiO2, lo que permitió una infiltración uniforme y profunda de los nanocristales de CIS. Utilizando la arquitectura BHJ hemos mejorado el rendimiento de las células solares de CQD de CIS, principalmente debido al aumento de las Jsc y los FFs, que conducen a incremento de seis veces en la eficiencia, del 0.15% inicial al 1.16%. A partir del análisis de las mediciones de Suns-Voc, -Jsc y Voc y Jsc transitorios, hemos identificado que los dispositivos de BHJ tienen una menor recombinación asistida por trampa y una menor energía de activación (EU) para la extracción de huecos. Esto fue confirmados por los cambios en la fotoluminiscencia del dispositivo total. Sugerimos que la estructura de BHJ permite el quenching de los tail states más profundos cerca de la nada de valencia en CIS por la transferencia de electrones de TiO2. En este trabajo, intentado introducir nanocristales de CIS en dispositivos optoelectrónicos, comenzando por precursores moleculares sintéticos hasta el diseño de estructuras supramoleculares. En cada etapa, hemos destacado el material y las propiedades de película y de dispositivos que serán necesarios para conseguir un buen rendimiento. Este trabajo tiene como objetivo final estimular un nuevo interés en futuros desarrollos de células solares de CQD de CIS, abriendo la posibilidad para fotovoltaicas no tóxicas de CQD.
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Pouget, Stéphanie. "Contribution à l'étude de l'influence de la dilution sur les propriétés magnétiques de composés isolants frustrés." Toulouse, INSA, 1993. http://www.theses.fr/1993ISAT0039.
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Nous avons principalement etudie le systeme ferromagnetique heisenberg-3d frustre cdcr#2#(#1##x#)in#2#xs#4, dans la limite des faibles dilutions x. La structure des phases ferromagnetiques et verre de spin reentrante a ete exploree par diffraction de neutrons et mesures d'aimantation macroscopiques. Les resultats s'interpretent dans le cadre d'un modele inhomogene du systeme de spins. Par diffusion de neutrons aux petits angles, spectrometries trois-axes et d'echo de spin, nous avons caracterise le comportement critique statique et dynamique des composes x=0 et 0. 05. Cette etude a revele la pertinence de la dilution et ainsi un des effets de la frustration qui est de porter le systeme dans la limite des forts desordres. Nos resultats suggerent l'existence de deux comportements statiques differents du compose cdcr#1#. #9in#0#. #1s#4, de part et d'autre de t#c, concernant la dynamique, nous avons mis en evidence une evolution non monotone du temps de relaxation en fonction du moment transfere, pour des valeurs de celui-ci tres inferieures a l'inverse de la longueur de correlation, et voisines de l'inverse de la distance moyenne entre impuretes in#3#+. La derniere partie de ce travail est consacree au systeme frustre ising-3d fe#1##xmg#xbr#2. Les mesures de la dispersion des ondes de spin pour differentes directions du moment transfere nous ont permis de preciser le modele des interactions d'echange pour le compose febr#2. Nous avons etudie la transition de phase para-antiferromagnetique pour les deux valeurs de la dilution x=0 et 0. 1. Les resultats sont interpretes dans le cadre d'une theorie classique de champ moyen
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Charbonneau, Sylvain. "Intensity dependent photoconductivity and photoluminescence in cadmium indium sulfide." Thesis, University of Ottawa (Canada), 1985. http://hdl.handle.net/10393/4725.
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Halverson, Adam Fraser 1978. "The role of sulfur alloying in defects and transitions in copper indium gallium diselenide disulfide thin films." Thesis, University of Oregon, 2007. http://hdl.handle.net/1794/6193.
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xv, 132 p. : ill. A print copy of this title is available from the UO Libraries, under the call number: SCIENCE TK7871.15.F5 H325 2007The effects of sulfur alloying on the electronic properties of CuIn(SeS) 2 and CuInGa(SeS) 2 materials has been investigated using sophisticated junction capacitance techniques including drive-level capacitance profiling and transient photocapacitance and photocurrent spectroscopies. CISSe and CIGSSe materials are used as absorber layers in thin-film photovoltaic devices. By characterizing the electronic properties of these materials we hope to understand how these materials can be improved to make thin-film devices with better conversion efficiencies. Sulfur widens the bandgap of these materials by moving the valence band to lower energies and the conduction band to higher energies. This significantly affects the electronic structure of these devices by increasing the activation energies of dominant acceptor levels and lowering room temperature free hole carrier densities. Using optical spectroscopies we observe a large, broad defect that also changes its apparent energetic depth with sulfur alloying. The occupation of this defect was controlled both optically and thermally, and showed a striking temperature dependence. This temperature dependence was measured by recording the relative defect signal, the ratio of the TPC signal in the defect regime to the above bandgap regime, as a function of temperature. As the temperature of the measurement was decreased, steps in the relative defect signal were observed, indicating the turning off of the thermal pathway that emptied trapped charge from the defect. Remarkably, such steps were seen at the same temperature in CISSe and CIGSSe devices with similar sulfur content. In addition, no steps were seen in CMS devices. This points to a defect state specific to the incorporation of sulfur in the absorber material. We hope that a better understanding of the electronic structure of these materials will assist in the creation of improved wide-bandgap thin-film photovoltaic devices.
Adviser: J. David Cohen
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Weïwer, Michel. "Acides de Lewis comme catalyseurs dans des réactions de macrocyclisation et de fonctionnalisation d'oléfines : applications en chimie des arômes et parfums." Nice, 2005. http://www.theses.fr/2005NICE4094.
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Les composés macrocycliques de la famille des substances à odeur musquée sont des composés clés utilisés dans de nombreux parfums, produits cosmétiques et d’entretien. Dans ce contexte, une partie de ce travail de thèse concerne l’étude de réactions de macrocyclisation pour la formation de lactones macrocycliques ainsi que la synthèse de nouveaux muscs aliphatiques. Le couplage réductif intramoléculaire de 1, □-dialdéhydes et de thiuesters a été étudié par voie électrochimique. D’autre part, la cycloisomérisation d’acides carboxyliques □-insaturés catalysée par des superacides protiques et de Lewis a été examinée. La synthèse d’une série d’esters aliphatiques a également été réalisée dans le but d’examiner les relations structure-odeur régissant l’odeur musquée. La deuxième partie de ce travail de thèse concerne l’addition de composés soufrés sur des oléfines non activées catalysée par des acides de Lewis dérivés de l’indium (III). La méthode développée a permis l’accès à de nombreux thioacétates, sulfures et thiols, composés importants en chimie des dérivés de l’indium (III). La méthode développée a permis l’accès à de nombreux thioacétates, sulfures et thiols, composés importants en chimie des arômes. Le système catalytique mis au point a été appliqué à la thioacétylation de dérivés terpéniques, pour la formation du 1-p-menthèn-8-thiol et de nouvelles structures dérivées du camphène. L’addition de thiols sur des dérivés de glycals a également été examinée et nous a conduit à l’obtention de thioglycosides 2,3-insaturés par réarrangement de Ferrier. Enfin, une étude mécanistique faisant appel à des analyses par RMN 1H, 13C et 115In ainsi qu’à des analyse en pH-métrie a permis de proposer une complexation entre le dérivé de l’indium (III) et le composé soufré, selon le concept LBA.
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Ghzizal, Abdelaziz el. "Contribution à l'optimisation des photopiles p-CuInSe2/n-CdS fabriquées par pulvérisation chimique réactive." Montpellier 2, 1989. http://www.theses.fr/1989MON20133.
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Ce travail est consacre pour une partie a l'etude approfondie des couches constituant la photopile p-culnse#2/n-cds. L'autre partie de ce travail est consacre a l'optimisation des parametres photovoltaiques de la photopile p-culnse#2/n-cds. Actuellement, le meilleur rendement de conversion est de 4% sur 1 cm#2 et de 5% sur 0,19 cm#2
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Halverson, Adam Fraser. "The role of sulfur alloying in defects and transitions in copper indium gallium diselenide disulfide thin films /." Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2007. http://hdl.handle.net/1794/6193.
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Thesis (Ph. D.)--University of Oregon, 2007.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 127-132). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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Rickman, Sarah. "Growth and characterization of molybdenum disulfide, molybdenum diselenide, and molybdenum(sulfide, selenide) formed between molybdenum and copper indium(sulfide, selenide) during growth." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.94 Mb., 85 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1435848.
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Saifi, Ali. "Contribution à l'étude des propriétés magnétiques des systèmes spinelles isolants CdCr2xIn2-2xS4 et ZnCr2xGa2-2xO4 : phases type verre de spin." Paris 6, 1986. http://www.theses.fr/1986PA066519.
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Ces systèmes présentent la percolation et la frustration. Le premier composé est ferromagnétique, tandis que le second présente des interactions antiferromagnétiques. On étudie en fonction de x les transitions de ces composés. Les transitions de phase du gallate ont été étudiées par effet Mössbauer. On a mis en évidence que pour x0,75 l'ordre magnétique tend vers un ordre caractéristique de la "vraie" phase verre de spin.
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Chen, Lihui. "Synthesis and Plasmonic Properties of Copper-based Nanocrystals." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217134.
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Benjelloun, Nadia. "Caracterisation des niveaux profonds dans le materiau photorefractif bi : :(12) geo::(20) par analyse de transitoires de courant photo-induit." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13183.
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La methode est utilisee pour l'etude de la densite d'etats dans la bande interdite du silicium amorphe hydrogene et sur cdin::(2)s::(4). La caracterisation des niveaux ayant des energies d'ionisation thermique entre 0,1 ev et 0,9 ev, le modele de transfert de charge decrivant l'effet photorefractif et l'evaluation du niveau de recombinaison, sont faits dans le materiau photorefractif. Les effets du dopage (fer) et du codopage (fer, vanadium) sur les niveaux sont consideres. Le centre responsable de la capture d'electrons est aussi etudie par absorption optique et photoconductivite photoinduites. Les resultats s'accordent avec ceux des mesures de photorefractivite
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Chen, Yuan Victor. "Fabrication et caractérisation des photopiles CdS/CuInSe2 entièrement obtenues par pulvérisation chimique réactive." Montpellier 2, 1987. http://www.theses.fr/1987MON20251.
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On montre la possibilite d'utiliser la technique de pulverisation chimique reactive pour la fabrication du materiau absorbeur cuinse::(2) et de la photopile cds/cuinse::(2). Les couches de cuinse::(2) presentent des proprietes cristallines, optiques et electriques comparables a celles obtenues par evaporation thermique sous vide. Le rendement photovoltaique obtenu est de 5% sous un eclairement de 100mw
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Frank, Anna Elisabeth Verfasser], Christina [Akademischer Betreuer] Scheu, and Jochen M. [Akademischer Betreuer] [Schneider. "Synthesis and in-depth electron microscopic characterization of solvothermally grown copper indium sulfide thin films / Anna Elisabeth Frank ; Christina Scheu, Jochen Michael Schneider." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1170586422/34.
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Frank, Anna Elisabeth [Verfasser], Christina Akademischer Betreuer] Scheu, and Jochen M. [Akademischer Betreuer] [Schneider. "Synthesis and in-depth electron microscopic characterization of solvothermally grown copper indium sulfide thin films / Anna Elisabeth Frank ; Christina Scheu, Jochen Michael Schneider." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1170586422/34.
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Rannou, Isabelle. "Etudes sous pression de la transition de phase interpolytypique du sulfure de gallium." Paris 6, 1986. http://www.theses.fr/1986PA066063.
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Etude entre 0 et dollar GPA, permettant de mettre en évidence une transition de basse pression à 1,6 GPA; mesures de l'absorption optique et de l'indice de réfraction, de la diffusion Raman et de la diffusion Brillouin; analyse des variations a la transition. Description satisfaisante des variations des modes de vibration au moyen d'un modèle de dynamique réticulaire a forces centrales.
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Deckelbaum, Ron Avi. "Regulation of chondrocyte differentiation by Indian hedgehog : modulation by parathyroid hormone-related peptide, engrailed-1, and heparan sulfate glycosaminoglycans." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84454.
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During the process of endochondral bone formation, Indian Hedgehog (Ihh), a member of the hedgehog (Hh) family of secreted morphogens, and parathyroid hormone-related peptide (PTHrP) play key roles in the regulation of cartilage cell (chondrocyte) differentiation. Previous studies have established that Ihh coordinates chondrocyte differentiation indirectly by activating PTHrP expression, which in turn delays their transition to the terminal hypertrophic state. In the present study, using an in vitro system of cultured CFK-2 chondrocytic cells, we have explored the possibility that Ihh may also influence chondrocytic differentiation directly and investigated how this process is modulated by PTHrP, Engrailed-1 (En-1), and heparan sulfate glycosaminoglycans (HS-GAG). We show that Ihh signaling enhances, rather than inhibits, expression of markers of chondrocytic differentiation and that an inactivating missense mutation mapping to its NH2-terminal domain (N-IhhW160G) abolishes this capacity. Moreover, activation of protein kinase A (PKA) by PTHrP-signaling also perturbs Ihh-mediated differentiation. Indicative of a novel regulatory mechanism, Ihh in turn downregulates PKA activity downstream of the PTH/PTHrP-receptor (PTH1R). En-1, detected in prehypertrophic growth plate chondrocytes in situ, influences chondrocytic differentiation and impedes Hh-signaling in vitro, suggesting a novel role for this protein in cartilage development. Finally, we show that HS-GAGS are required for proper mediation of Hh-signaling and thus also participate in modulating chondrocytic differentiation. Taken together, this study provides experimental evidence that Ihh harbors the capacity to directly induce rather than impede chondrogenic differentiation, and that this function is modulated by the cellular actions of PTHrP, En-1, and HS-GAG.
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Gutta, Venkatesh. "INVESTIGATIONS OF CuInTe2 / CdS & CdTe / CdS HETEROJUNCTION SOLAR CELLS." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/654.
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Thin film solar cells of Copper Indium Telluride and Cadmium Sulfide junctions were fabricated on plain ITO glass slides and also on those coated with intrinsic Tin Oxide. CdS was deposited through chemical bath deposition and CIT by electrodeposition. Both compounds were subjected to annealing at temperatures between 350°C and 500°C which produced more uniform film thicknesses and larger grain sizes. The CIT/ CdS junction was characterized after performing XRD and spectral absorption of individual compounds.
Studies were also made on CdS / CdTe solar cells with respect to effect of annealing temperatures on open circuit voltages. NP acid etch, the most important process to make the surface of CdTe tellurium rich, was also studied in terms of open circuit voltages. Thermally evaporated CdS of four different thicknesses was deposited on Tin Oxide coated ITO and inferences were drawn as to what thickness of CdS yields better results.
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Hauschild, Dirk [Verfasser], and Friedrich Theodor [Gutachter] Reinert. "Electron and soft x-ray spectroscopy of indium sulfide buffer layers and the interfaces in Cu(In,Ga)(S,Se)2-based thin-film solar cells / Dirk Hauschild. Gutachter: Friedrich Theodor Reinert." Würzburg : Universität Würzburg, 2016. http://d-nb.info/1111784574/34.
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Trichard, Florian. "Étude de la spectrométrie de plasma induit par laser pour l’analyse en ligne de liquides." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10311/document.
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Le contrôle des procédés représente un enjeu majeur pour les industries chimiques et pétrochimiques afin de garantir la qualité des produits, le contrôle des coûts, le maintien de la productivité et la maîtrise des risques. L'analyse menée directement au coeur des procédés constitue la voie la plus efficace. Cependant, dans la majorité des applications, les analyses élémentaires sont réalisées essentiellement en laboratoire et très rarement en ligne, par la mise en oeuvre de différentes technologies, le plus souvent lourdes et onéreuses. Ce travail de thèse s'inscrit dans le cadre d'un grand projet d'innovation qui couvre le champ de l'analyse élémentaire en ligne, domaine actuellement peu étudié. La technique d'analyse retenue est la spectrométrie LIBS en raison de sa rapidité et de son application à tout état de la matière sans préparation d'échantillon, ce qui lui offre un fort potentiel pour l'analyse en ligne. Cette technique est investiguée afin de réaliser des analyses en ligne d'éléments présents dans des matrices liquides : saumures, huiles silicone et produits pétroliers. L'optimisation des différents paramètres de mesure est réalisée et une approche d'optimisation s'appuyant sur un plan d'expériences est proposée. Différents modes d'échantillonnage de liquide et plusieurs montages LIBS sont étudiés afin de répondre aux problématiques évoquées. Enfin, une transposition au monde industriel est présentée avec le suivi du soufre en ligne dans des produits pétroliers sur un pilote industriel. Les résultats sont encourageants, mais la stabilité perfectible des mesures dans le temps implique d'explorer de nouvelles pistes d'améliorationProcess control is a major challenge for chemical and petrochemical industries so as to ensure product quality, cost control, sustainable productivity and risk management. To do so, carrying out the analysis directly at the core of the process is the most efficient way. However, for most applications, elemental analyzes are mainly performed in the laboratory and rarely on-line, which requires the implementation of different technologies, usually complex and expensive. This work is part of a large innovative project that covers the field of on-line elemental analysis, a research area still understudied to this day. The analytical technique selected here is the Laser Induced Breakdown Spectroscopy. Indeed, its speed and its capability to analyze all states of matter without sample preparation, gives it a great potential for on-line analysis. This technique is investigated in order to achieve on-line analysis of elements contained in various liquid matrices: brines, silicone oils and petroleum products. The optimization of different measurement parameters is performed, including an experimental design based approach. Different liquid sampling configurations and several LIBS setups are designed in order to tackle the issues encountered. Finally, a transposition to the industrial world is presented through on-line monitoring of sulfur in petroleum products on an industrial pilot process. The results are promising, but improving the stability of measurements over time still requires further research
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Mirsaleh, Kohan Leila. "Comparison of the Effects of Cobalt-60 [gamma]-Rays and Tritium [beta][superscript -]Particles on Water Radiolysis and Aqueous Solutions and Radiolysis of the Ceric-Cerous Sulfate Dosimeter at Elevated Temperature." Mémoire, Université de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/168.
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Abstract : Monte Carlo simulations have proven to be very powerful techniques to study the radiolysis of water and the mechanisms underlying this radiolysis. Monte Carlo simulations particularly become important when there are no experimental results available in the literature due, for instance, to the difficulty of performing such experiments. This thesis presents a study of the radiolysis of water irradiated by different types of radiation and at various temperatures, employing Monte Carlo simulations. The first part of the thesis uses Monte Carlo simulations to elucidate the mechanisms involved in the self-radiolysis of tritiated water and to examine the importance of the effects of higher “linear energy transfer” (LET) by comparing [[superscript 3]H [beta][superscript -] radiations (mean initial energy of ~5.7 keV) with [superscript 60]Co [gamma]-rays (~1 MeV electrons). Our simulations showed that, for [superscript 3]H [beta][superscript -], we observe lower radical and higher molecular yields than in γ-radiolysis. These differences in yields are consistent with differences in the nonhomogeneous distribution of primary transient species in the two cases. Overall, our results corroborate well with previously reported work, and support a picture of [superscript 3]H [beta][superscript -] radiolysis mainly driven by the chemical action of “short tracks” of high local LET. This same trend in yields of radical and molecular products was also found under acidic conditions as well as in the aerated Fricke dosimeter. One of our main findings was that the measured Fricke yield G(Fe[superscript 3+]) could be best reproduced if a single, mean “equivalent” electron energy of ~7.8 keV were used to mimic the energy deposition by the tritium [beta][superscript -] particles (rather than the commonly used mean of ~5.7 keV), in full agreement with a previous recommendation of ICRU Report 17. The second part of this thesis investigates the radiolysis of the ceric-cerous sulfate dosimeter at elevated temperatures. In this radiolysis, H[superscript •] (or HO[subscript 2][superscript •] in the presence of oxygen) and H[subscript 2]O[subscript 2] produced by the radiolytic decomposition of water both reduce Ce[superscript 4+] ions to Ce[superscript 3+] ions, while [superscript •]OH radicals oxidize the Ce[superscript 3+] present back to Ce[superscript 4+]. Our simulations showed that the net Ce[superscript 3+] yield decreases almost linearly with increasing temperature up to ~250 °C, in excellent agreement with experiment. Above 250 °C, our model predicts that G(Ce[superscript 3+]) drops markedly with temperature until, instead of Ce[superscript 4+] reduction, Ce[superscript 3+] oxidation is observed. This drop is shown to result from the occurrence of the reaction of H[superscript •] atoms with water in the homogeneous chemical stage.//Résumé : La méthodologie de simulation Monte-Carlo s’est révélée être une très puissante technique dans l’étude des mécanismes de la radiolyse de l’eau. En particulier, la simulation Monte-Carlo se rend même plus importante quand les résultats expérimentaux ne sont pas disponibles, notamment dû aux difficultés techniques. Le mémoire actuel représente une étude sur la radiolyse de l’eau irradiée par différents rayonnements à différentes températures, en utilisant la simulation Monte-Carlo. Dans la première partie de ce mémoire, on examine les mécanismes d’auto-radiolyse de l’eau tritiée ainsi que l’importance de l’effet de « transfert linéaire d'énergie » (TLE) en comparant les électrons [béta][indice supérieur -] de [indice supérieur 3]H avec les rayons [béta][indice supérieur -] de [indice supérieur 60]Co. Nos simulations montrent que, pour les rayons [béta][indice supérieur -] de [indice supérieur 3]H, on observe moins de production de radicaux libres et plus de produits moléculaires. Ces différences de rendement sont en accord avec les différences de distribution non-homogène des espèces primaires transitoires dans les deux cas. En résumé, nos résultats corroborent bien avec les travaux publiés précédemment et donnent une perspective de la radiolyse [béta][indice supérieur -] de [indice [supérieur 3]H qui est en majorité contrôlée par l’action chimique de « trajectoires courtes » de TLE local élevé. La même tendance pour la production des radicaux libres et des produits moléculaires a été trouvée en milieu acide ainsi que pour le dosimètre aéré de Fricke. Un de nos résultats principaux montre que le rendement G(Fe[indice supérieur 3+]) du dosimètre de Fricke peut être mieux reproduit si une seule énergie électronique moyenne « équivalente » de ~7.8 keV est utilisée pour mimer la déposition d’énergie par les particules [béta][indice supérieur -] du tritium (au lieu de la valeur moyenne de ~5.7 keV qui est utilisée fréquemment). Ceci est en complet accord avec une recommandation du rapport 17 de l’ICRU. La deuxième partie de ce mémoire concerne la radiolyse du dosimètre au sulfate cérique-céreux à températures élevées. Lors de cette radiolyse, H[indice supérieur •] (ou HO[indice inférieur 2][indice supérieur •] en présence d’oxygène) et H[indice inférieur 2]O[indice inférieur 2] produits par la décomposition radiolytique de l’eau réduisent les ions cériques Ce[indice supérieur 4+] en ions céreux Ce[indice supérieur 3+], tandis que les radicaux [indice supérieur •]OH oxydent Ce[indice supérieur 3+] en Ce[indice supérieur 4+]. Nos simulations montrent que le rendement G (Ce[indice supérieur 3+]) décroît quasi linéairement avec la température entre 25 et 250 ° C, en excellent accord avec l’expérience . Au-dessus de 250 °C, notre modèle prédit une diminution marquée de G (Ce[indice supérieur 3+]) jusqu’à ce qu’on l’observe, au lieu d’une réduction de Ce[indice supérieur 4+], une oxydation de Ce[indice supérieur 3+]. Nous montrons que cette diminution est due à l’intervention de la réaction des atomes H[indice supérieur •] avec l’eau en milieu homogène.
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Nagamine, Gabriel 1992. "Revelando a estrutura eletrônica de nanomateriais através de espectroscopia óptica avançada." [s.n.], 2017. http://repositorio.unicamp.br/jspui/handle/REPOSIP/325655.
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Orientador: Lázaro Aurélio Padilha JuniorDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
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Resumo: Pontos quânticos coloidais (QDs) ternários de CuInS2 (CIS) surgiram como uma alternativa não tóxica, altamente promissora, aos já bem estabelecidos QDs binários de CdX e PbX (X=Se,S). Além de não possuírem metais pesados em sua composição, esses novos materiais apresentam diversas características desejáveis, o que os torna fortes candidatos a serem aplicados em novas tecnologias, tanto em biologia quanto na geração de nova fontes de energia renovável. Além disso, esses QDs apresentam diversas propriedades ópticas que os diferem radicalmente dos QDs binários já conhecidos e ainda são pouco compreendidas. Dentre elas, podemos citar um largo espectro de fotoluminescência (PL), com decaimentos longos e multi-exponenciais e um espectro de absorção pouco definido, com uma longa cauda que vai para o infravermelho. Adicionalmente, esses nanomateriais apresentam um grande Stokes shift, de até 500 meV, cuja origem ainda é desconhecida e amplamente debatida na literatura. Com o intuito de desvendar os mecanismos por trás dessas propriedades distintas, nesse trabalho, realizamos uma série de estudos da sua dinâmica ultrarrápida e de espectroscopia não-linear para revelar a estrutura eletrônica desses QDs. Das medidas de dinâmica ultrarrápida, mostramos uma maneira alternativa de medir-se o tamanho dessas nanopartículas, por meio da sua seção de choque de absorção em 3,1 eV, que seria independente da variabilidade morfológica apresentada por elas. Adicionalmente, fazendo um estudo da dependência das interações multi-éxciton desses QDs com o tamanho, reportamos que esses nanomateriais apresentam interações Coulombianas reduzidas em relação aos QDs binários já conhecidos. Das medidas de espectroscopia não-linear, mostramos a primeira comprovação experimental de que a transição óptica entre os níveis fundamentais da banda de valência e condução é proibida por paridade em partículas esféricas. Além disso, comparando o espectro de absorção de 2 fótons das amostras estudadas com imagens de microscopia eletrônica de transmissão (TEM), mostramos que quebras na simetria das funções de onda dos portadores nesses QDs alteram as suas regras de seleção para transições ópticas. Adicionalmente, verificamos que, controlando a composição e tamanho desses QDs, é possível obter seções de choque de 2PA de até 13.500 GM dentro da janela de transparência óptica do tecido do corpo humano
Abstract: Ternary CuInS2 (CIS) Colloidal Quantum Dots (QDs) have emerged as a non-toxic promising alternative to the CdX and PbX (X=Se,S) binary QDs. Besides not having heavy metals on their composition, these new materials show several desirable features, which makes them strong candidates to be applied in new technologies, from biology to the new generation of renewable energy sources. Furthermore, these QDs present various optical properties that radically differs from the already well studied binary QDs and yet are not well understood. Among them, we can cite a large photoluminescence (PL) spectra, with long and multi-exponential decays and a poorly defined absorption spectra, with a long infrared tail. Additionally, these nanomaterials present large Stokes shift, up to 500 meV, whose origin is still not well understood and largely debated on the literature. To reveal the mechanism behind these distinguished properties, here, we perform a series of ultrafast spectroscopy and non-linear spectroscopy studies to reveal the electronic band structure of these QDs. From the ultrafast dynamics measurements, we show an alternative way to measure the size of these nanoparticles, through their absorption cross section in 3,1 eV, which would be independent from the morphologic variability presented by them. Additionally, by performing studies of the size dependent multi-exciton interactions, we report that these kind of nanomaterials present reduced Coulombic interactions in relation to de already known binary QDs. From the non-linear spectroscopy measurements, we show the first experimental confirmation that the optical transition between the electron and hole ground state are parity forbidden in the spherical particles. In addition, comparing the two-photon absorption (2PA) spectra of the studied samples with their transmission electron microscopy images, we show that symmetry breaking of the electronic wave functions in these QDs change their optical transition selection rules. Additionally, we verify that, by controlling the size and composition of these QDs, it is possible to obtain 2PA cross section as high as 13,500 GM inside the transparency window of the human tissue
Mestrado
Física
Mestre em Física
1547612/2015
13/16911-2
CAPES
FAPESP
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Raevskaya, Alexandra, Oksana Rozovik, Anastasiya Novikova, Oleksandr Selyshchev, Oleksandr Stroyuk, Volodymyr Dzhagan, Irina Goryacheva, Nikolai Gaponik, Dietrich R. T. Zahn, and Alexander Eychmüller. "Luminescence and photoelectrochemical properties of size-selected aqueous copper-doped Ag–In–S quantum dots." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-235077.
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Ternary luminescent copper and silver indium sulfide quantum dots (QDs) can be an attractive alternative to cadmium and lead chalcogenide QDs. The optical properties of Cu–In–S and Ag–In–S (AIS) QDs vary over a broad range depending on the QD composition and size. The implementation of ternary QDs as emitters in bio-sensing applications can be boosted by the development of mild and reproducible syntheses directly in aqueous solutions as well as the methods of shifting the photoluminescence (PL) bands of such QDs as far as possible into the near IR spectral range. In the present work, the copper-doping of aqueous non-stoichiometric AIS QDs was found to result in a red shift of the PL band maximum from around 630 nm to ∼780 nm and PL quenching. The deposition of a ZnS shell results in PL intensity recovery with the highest quantum yield of 15%, with almost not change in the PL band position, opposite to the undoped AIS QDs. Size-selective precipitation using 2-propanol as a non-solvent allows discrimination of up to 9 fractions of Cu-doped AIS/ZnS QDs with the average sizes in the fractions varying from around 3 to 2 nm and smaller and with reasonably the same composition irrespective of the QD size. The decrease of the average QD size results in a blue PL shift yielding a series of bright luminophors with the emission color varies from deep-red to bluish-green and the PL efficiency increases from 11% for the first fraction to up to 58% for the smallest Cu-doped AIS/ZnS QDs. The rate constant of the radiative recombination of the size-selected Cu-doped AIS/ZnS QDs revealed a steady growth with the QD size decrease as a result of the size-dependent enhancement of the spatial exciton confinement. The copper doping was found to result in an enhancement of the photoelectrochemical activity of CAIS/ZnS QDs introduced as spectral sensitizers of mesoporous titania photoanodes of liquid-junction solar cells.
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Lox, Josephine F. L., Zhiya Dang, Volodymyr Dzhagan, Daniel Spittel, Beatriz Martín-García, Iwan Moreels, Dietrich R. T. Zahn, and Vladimir Lesnyak. "Near-Infrared Cu-In-Se-Based Colloidal Nanocrystals via Cation Exchange." ACS Publications, 2019. https://tud.qucosa.de/id/qucosa%3A36557.
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We developed a three-step colloidal synthesis of near-infrared active Cu-In-Se (CISe)/ZnS core/shell nanocrystals (NCs) via a sequential partial cation exchange. In the first step binary highly copper deficient Cu2‒xSe NCs were synthesized, followed by a partial cation exchange of copper to indium ions yielding CISe NCs. In order to enhance the stability and the photoluminescence (PL) properties of the NCs, a subsequent ZnS shell was grown, resulting in CISe/ZnS core/shell NCs. These core/shell hetero-NCs exhibited a dramatic increase in size and a restructuring to trigonal pyramidal particles. The reaction parameters, e.g. the Cu:Se-ratio, the temperature and the time were carefully tuned enabling a distinct control over the size and the composition of the NCs. By varying only the size of the CISe/ZnS NCs (from 9 to 18 nm) the PL spectra could be tuned covering a wide range with maxima from 990 nm to 1210 nm. Thus, in these experiments we demonstrate a clear dependence of the optical properties of these materials on their size and extend the PL range of CISe-based nanoparticles further to the infrared part of the spectrum. Furthermore, the relatively large size of these NCs allows their detailed structural analysis via electron microscopy techniques, which is particularly challenging in the case of small particles and especially important to relate the size, composition and crystal structure to their optoelectronic properties.
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Desprez, Alain. "Caractérisation moléculaire et élémentaire des produits pétroliers lourds." Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3052.
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Les pétroles utilisés en raffinage étant de plus en plus lourds et chargés en métaux et hétéroélements, il est d’une grande importance pour les activités de raffinage de connaître la spéciation de ces espèces au sein des produits pétroliers et leurs comportements durant les procédés de raffinage. Afin d’apporter des réponses à cette problématique des techniques de caractérisation élémentaire et moléculaire ont été utilisées notamment par ICP MS Haute Résolution et FT ICR MS respectivement. Ces techniques analytiques sont appliquées à différents échantillons pétroliers provenant parfois de procédés de raffinage et les informations obtenues au niveau élémentaire et moléculaire sont utilisées de manières complémentaires pour améliorer notre compréhension des mécanismes se produisant au sein de nos échantillons durant les activités de raffinageThe crude oils available for the refining industry are heavier and heavier and more concentrated in metals and heteroelements. It is thus of great importance to study the speciation of these species within the petroleum products and their behavior during the refining processes. To answer that problematic, elemental and molecular characterization techniques have been used, mainly High Resolution ICP MS and FT ICR MS for the elemental and molecular characterization respectively. The analytical techniques quoted are used for the analysis of several petroleum products sometimes originating from refining processes and the information obtained at the elemental and molecular level are combined to improve our understanding of the mechanisms occurring within our samples during refining activities
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Gutiérrez, Sama Sara. "Identifications moléculaires des espèces hétéroatomiques et métalliques en lien avec les procédés d’hydrodemetallation et d’hydroconversion." Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3042.
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La présence d'hétéroatomes et métaux dans des fractions lourdes de pétrole brut peuvent entraîner la désactivation des catalyseurs d’hydrotraitement et d’hydrocraquage. Les composés contenant ces éléments sont connus pour être inclus dans des agrégats macromoléculaires d’asphaltènes, qui sont considérées comme les composants les plus problématiques des produits pétroliers. Ces travaux ont pour objectif d’apporter une meilleure compréhension de l’environnement chimique de ces espèces et des phénomènes d’agrégation pour optimiser les processus de raffinage. Des techniques de séparation comme la chromatographie de perméation de gel ou Gel Permeation Chromatography (GPC), Advanced Polymer chromatographie (APC) et la chromatographie sur couche mince d’haute performance ou High Performance Thin Layer Chromatography (HPTLC) ont été combinées avec des techniques d’analyse élémentaire comme la spectrométrie de masse à plasma à couplage inductif ou Inductively Coupled Plasma Mass Spectrometry (ICP-MS) et la spectrométrie de masse moléculaire d’haute résolution pour la caractérisation des fractions pétrolières lourdes. Les profils de distribution en taille d’espèces qui contiennent du vanadium, du nickel et du soufre, les hétéroatomes et métaux les plus abondants dans les produits pétroliers, ont été déterminés par GPC couplé à une détection élémentaire par ICP MS. Les paramètres ayant le plus d’impact sur la distribution en taille et l’évolution des agrégats dans les solutions de différentes coupes pétrolières ont été optimisés. Cela nous a permis de faire différentes comparaisons, entre de nombreuses charges et effluents de procédés, ainsi que d’autres séries d’échantillons ou de mélanges provenant d’unités-pilotes d’hydrotraitement. Les résultats obtenus ont pu être mis en regard de caractéristiques macroscopiques comme la viscosité. Le couplage du nouveau système APC avec l’ICP MS a été mis au point avec succès. Cette technique a permis de réaliser des cartographies d’échantillons pétroliers plus rapides qu’en GPC tout en consommant moins de solvant. Cependant, les différences des chromatogrammes APC obtenus par rapport aux profils GPC suggèrent des interactions indésirables avec la phase stationnaire, qui ont été l’objet d’une évaluation approfondie.Enfin, un dernier type de séparation a été évaluée. L’HPTLC, qui utilise des plaques à usage unique, peut être appliquée à la séparation de produits lourds par polarité, et ce sans étapes de déasphaltage préalable, contrairement aux colonnes de chromatographie liquide qui peuvent être détériorées à cause de l'adsorption irréversible et de la précipitation des asphaltènes. Différents types de plaques et éluants ont été testés afin de développer une méthode simple pour la séparation des fractions SAR (Saturés, Aromatiques et Résines) des échantillons de distillat sous vide ou Vacuum Gas Oil (VGO). Ce travail avait pour but des migrations en une seule étape et analyse UV qui pourrait être mis en œuvre pour l’analyse de routine dans les laboratoires de contrôle avec une adsorption irréversible réduite. Des résultats très prometteurs ont été obtenus avec l’utilisation de plaques de cellulose pour la séparation des familles de polarité différentes au sein des agrégats d’asphaltènes. Des tests sur l'analyse directe des plaques par Désorption-Ionisation par Électronébulisation (DESI) MS, l'analyse directe en temps réel ou Direct Analysis in Real Time (DART) MS et Ablation Laser (LA) ICP MS ont été effectuésThe presence of heteroatoms and metals in heavy fractions of crude oil can cause the deactivation of hydrotreatment and hydrocracking catalysts. Compounds containing these elements are known to be included in macromolecular asphaltene aggregates, which are considered the most problematic components of heavy oil. This thesis aimed for a better understanding of the chemical environment of these species and on the aggregation phenomenon to optimize refining processes. Separation techniques such as Gel Permeation Chromatography (GPC), Advanced Polymer Chromatography (APC) and High Performance Thin Layer Chromatography (HPTLC) were combined with elementary analysis techniques such as Inductively Coupled Plasma Mass Spectrometry (ICP MS) or high-resolution molecular mass spectrometry for the characterization of heavy fractions of crude oil. Here, the size profiles of species that contain vanadium, nickel and sulfur, the most abundant heteroatoms and metals present in petroleum products, were determined by GPC online with elemental detection by ICP MS. The parameters having the most significant impact on size distribution and the evolution over time of aggregates from solutions of different petroleum cuts were optimized. This allowed the comparison between various feeds and effluents and other series of samples and mixtures from pilot units of refining processes by GPC ICP MS. Results obtained could be related to macroscopic characteristics such as viscosity. Hyphenation of the new APC System to ICP MS has been successfully completed. It allowed the mapping of petroleum samples faster than GPC, therefore with less solvent consumption. However, the differences of the APC chromatograms obtained with respect to the GPC profiles suggested significant unwanted interactions of the highly polar compounds of the petroleum samples with the stationary phase, which have been thoroughly studied. Finally, another type of separation was evaluated. HPTLC, of single-use plates, can be applied to the analysis of heavy petroleum products by polarity without prior deasphalting steps while chromatography columns can be deteriorated because of the irreversible adsorption and asphaltene precipitation. To this end, various types of plates and eluents were tested to develop straightforward SAR (Saturates, Aromatics and Resins) separations of Vacuum Gas Oil (VGO) samples. This method, based on single-step migrations with reduced irreversible adsorption and UV monitoring, could be implemented for routine analysis in control laboratories. Very promising results were obtained by the use of cellulose plates for the separation of different families within asphaltene aggregates. Tests on Desorption ElectroSpray Ionization (DESI) MS, Direct Analysis in Real Time (DART) MS and Laser Ablation (LA) ICP MS analyses of the plates have been performed
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Nouvelot, Luc. "Evaluation et réalisation de miroirs diélectriques à profil d'indice continu et périodique (filtres rugates)." Grenoble 1, 1993. http://www.theses.fr/1993GRE10069.
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Differentes methodes de calcul des proprietes optiques des couches minces optiques a profil d'indice continu sont presentees. Dans le cas des filtres rugates, l'utilisation de methodes analytiques a notamment permis un calcul des enveloppes des spectres ainsi que l'optimisation du profil d'indice. Un nouveau systeme de coevaporation sous vide a ete developpe pour realiser des filtres a profil d'indice continu. Des couches minces homogenes de zns, znse, mgf#2, ainsi que de zns-mgf#2 et de znfe-mgf#2 de differentes compositions ont ete realisees. Il apparait que le zns presente un probleme de condensation lorsqu'il est codepose avec du mgf#2, meme sur substrat froid. Le znse ne presente pas ce probleme lorsque celui-ci est majoritaire dans un melange realise a froid. Des filtres rugates a profil d'indice sinusoidal, comportant jusqu'a 20 periodes, ont ete realises en znse-mgf#2 depose sur substrat froid. Leurs spectres de reflexion et de transmission sont conformes aux simulations numeriques. Un atout important des filtres rugates par rapport aux multicouches a par ailleurs ete mis en evidence: les faibles contraintes dans les couches de melanges znse-mgf#2 et dans les filtres realises devraient autoriser la realisation de films epais, ce qui est une necessite pour la realisation de miroirs de faible largeur de bande
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Shih, Jhih-Lin, and 施志霖. "Synthesis and Characterization of Indium Sulfide/Indium Oxide Nanowire Heterostructures." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/72062994700487891518.
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碩士國立東華大學
材料科學與工程學系
103
In2S3/In2O3 nanowire heterostructures have been successfully synthesized on silicon substrate by combining physical and chemical methods in this study. First, the In2O3 nanowires were grown on silicon substrate by vapor transport process. Then In2S3 were grown onto In2O3 nanowire surfaces using thioacetamide as a source of sulfide ions by hydrothermal method. And the thickness of In2S3 can be increased significantly through adjusting sulfurization pH values. Both scanning electron microscopy and X-ray diffraction results confirm the formation of In2S3 nanosheets/In2O3 nanowire heterosructures by sulfurization. Transmission electron microscopy and X-ray photoe-lectron spectroscopy results show that In2S3/In2O3 nanowire heterostructures are type II core-shell heterostructures, and the crystal structure of In2S3 is α-In2S3. UV/visible absorption spectroscopy results indicate that the In2S3/In2O3 nanowire heterostructures exhibit excellent visible-light absorption property. Photoluminescence results reveal that the near-infrared emissions come from defect emission from In2S3. Time-resolved photoluminescence results indicate that In2S3/In2O3 heterostructures can prolong charge carrier life time from 0.12 ns (In2O3) to 0.6 ns (In2S3/In2O3, pH 6). Finally, visi-ble light photocatalytic activity measurements reveal that the photocatalytic activity is enhanced significantly in In2S3/In2O3 nanowire heterostructure due to a longer charge carrier life time (pH 6), and the reaction rate constant is 0.460 (h-1).
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CHEN, KUAN-WEN, and 陳冠文. "Optimization and Characterization of Indium Cadmium Sulfur-based Photocatalysts." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/299kx9.
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碩士逢甲大學
化學工程學系
106
Due to global energy and environmental issues, the use of visible light catalyzed photocatalysts in solar energy to decompose water and produce hydrogen gas is an environmentally friendly and clean method. Cadmium sulfide (CdS) is a visible light absorption photocatalyst. The advantages of CdS are small energy gap and low cost, but CdS suffers light corrosion and it is not environmentally friendly. Our previous research found that In0.2Cd0.8S photocatalyst has better photocatalytic activity than CdS. In order to reduce cadmium content and enhance its photocatalytic activity, the piezoelectric injection system combined with scanning electrochemical microscope is used for screening of new composition of the photocatalysts. The Mx(In0.2Cd0.8)1-xS photocatalyst array was prepared and screened. The results show that Ga0.3(In0.2Cd0.8)0.7S has the best photocatalytic activity. The photocurrent of the Ga0.3(In0.2Cd0.8)0.7S photocatalyst has 4 times higher than that of the In0.2Cd0.8S photocatalyst. The carrier concentration of the Ga0.3(In0.2Cd0.8)0.7S photocatalyst has 2.3 times higher than that of the In0.2Cd0.8S photocatalyst, resulting in higher photocatalytic activity. The photoelectric conversion efficiency of the Ga0.3(In0.2Cd0.8)0.7S photocatalyst can reach 73% at 400 nm. Graphene and graphene oxide have low resistance and high transmittance. When they are added into semiconductors, the energy gap of semiconductors can be reduced. Graphene and graphene oxide doped In0.2Cd0.8S photocatalysts are also discussed in this study. Results show that The photocurrent of the 0.05 wt% graphene-In0.2Cd0.8S and 0.1 wt% graphene oxide-In0.2Cd0.8S is increased 2 times. and 2.5 times than that of the pure In0.2Cd0.8S photocatalysts. The carrier concentration of the 0.05 wt% graphene-In0.2Cd0.8S and 0.1 wt% graphene oxide-In0.2Cd0.8S is increased 1.5 times and 2.3 times than that of the pure In0.2Cd0.8S photocatalysts. The addition of the graphene and graphene oxide could increase the generation probability of electron hole pair resulting in enhancing the photocatalytic activity of photocatalysts. Key word: Photocatalyst, SECM, CdS, GaS, Graphene.
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Hsu, Wen-Chia, and 許文嘉. "The Synthesis and Characteristization of One-Dimensional Indium Sulfide." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/03275915774216874867.
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碩士逢甲大學
電子工程所
96
In order to fabricate the nanoporous anodic aluminum oxide (AAO) from the high purity aluminum by anodization process, to carefully control the electrolyte of concentration, temperature and pH value, and precisely support the voltage current and work time, the nanoporous anodic aluminum was formed with uniform porous and regularly ordered nanochannel. To fill the indium element into the nanochannel of anodic aluminum by electrochemical deposition method, then put the anodic aluminum oxide and Sulfide powder in the glass tube. The glass tube was evacuated by using a pump, and it was placed into the furnace and heated from temperature to 500℃ for 10 hours. To observed the sample appearance by FESEM instrument in experimental process. The element condition was determined by EDS, and demonstrated the structure of indium sulfide nanowires by X-ray diffraction, to measure the absorbance spectrum by UV machine.
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CHIU, KE-CHIH, and 邱科智. "Screening and Characterization of Indium Cadmium Sulfur-based Photocatalysts and Their Applications." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/19185620325817930757.
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Tsai, Chi-Lu, and 蔡奇陸. "Zinc Indium Sulfide and Zinc Oxide Nanocomposites for Photocatalytic Application." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g9p28x.
Full textAbstract:
碩士逢甲大學
材料科學與工程學系
107
Abstract This present study has been used a facile hydrothermal method to grow zinc indium sulfide nanosheets. The zinc indium sulfide and zinc oxide nanocomposites with the different weight of zinc indium sulfide nanosheets were not only controlled the surface-to-volume ratio, but also influenced their optical property. The photocatalytic activities of zinc indium sulfide and zinc oxide nanocomposites were evaluated in the photocatalytic degradation of 4-Aminobenzoic acid under the blue and white light LED irradiation. The zinc indium sulfide and zinc oxide nanocomposites revealed much higher photodegradation efficiency than zinc indium sulfide nanosheets. In addition, zinc indium sulfide and zinc oxide nanocomposites exhibited the better hydrogen production rate under the blue and white light LED irradiation. The novel zinc indium sulfide and zinc oxide nanocomposites will offer promising applications, such as solar energy conversion and energy storage.
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Knapp, Michael W. "Continuous flow synthesis of lead sulfide and copper indium diselenide nanocrystals." Thesis, 2012. http://hdl.handle.net/1957/31351.
Full textAbstract:
The use of size and shape tunable quantum confinement nanocrystals has many potential applications for use in semiconductors, optics and sensors. The synthesis of lead sulfide (PbS) and copper indium diselenide (CuInSe���) nanoparticles are of particular interest for use in semiconductor, optoelectronics and bio-medical applications.
The continuous synthesis of lead sulfide (PbS) and copper indium diselenide (CuInSe���) nanocrystals was undertaken in this work. Quality colloidal nanocrystal synthesis requires three components: precursors, organic surfactants and solvents. The synthesis of the nanocrystals can be thought of as a nucleation event, followed by a subsequent growth period. Both the nucleation and growth rates were found to be dependent upon factors such as temperature, growth time, and precursor concentration. For a continuous flow system the residence time (at nucleation and growth conditions) was also found to be important. In order to separate the nucleation and growth events, injection techniques were employed to achieve rapid nucleation of nanocrystals with final size dictated by the growth temperature and/or residence time through the growth zone of the reaction system.
Experimental parameters to investigate the size, shape, and composition of synthesized nanocrystals included injection temperature, growth temperature,
residence time, and concentration of organic surfactants. Size tunability was accomplished for both PbS and CuInSe��� nanocrystals where particle sizes less than 10 nm were achieved and the resulting nanocrystal compositions were found to be at the approximate stoichiometric ratios for both PbS and CuInSe���. The materials used for the process tubing and pumps were found to be important as chlorinated reaction byproducts were found to react with the stainless steel tubing and pump heads. Post processing was also found to be important in order to remove any possible reaction by-products and residual precursors from the surface of synthesized nanocrystals.
When at least one dimension of the nanocrystal approaches the exciton Bohr radius, the bandgap for the nanocrystal increases. UV-VIS spectroscopy was used to optically characterize synthesized PbS nanocrystals from our continuous flow synthesis. The absorption spectra for the particles demonstrated an absorption onset showing a large blueshift compared to that of bulk PbS. The blueshift matches closely with literature reports of the quantum confinement effect that would be desired when synthesizing PbS nanoparticles at diameters that are less than the PbS exciton Bohr radius of 18 nm.Graduation date: 2013
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Kallaher, Raymond L. "Electron tunneling transport across heterojunctions between europium sulfide and indium arsenide." 2007. http://etd.lib.fsu.edu/theses/available/etd-06162007-123639.
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Thesis (Ph. D.)--Florida State University, 2007.Advisor: Stephan von Molnár, Florida State University, College of Arts and Sciences, Dept. of Physics. Title and description from dissertation home page (viewed Oct. 10, 2007). Document formatted into pages; contains xviii, 109 pages. Includes bibliographical references.
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Wang, Pei-Ying, and 王蓓瑛. "Enhancement of Photocatalytic Activity of Silver-Indium-Zinc Sulfide Solid Solutions." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/73396547033189699577.
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碩士國立中正大學
化學工程研究所
100
The energy and greenhouse effect are big challenges of 21st century. Hydrogen is the most promising replacement for fossil fuels without any pollutant emission. The development of visible-light-driven photocatalysts for water splitting is critical. The (Ag-In-Zn)S solid solution has a high activity with a hydrogen evolution rate of 7.37 µmol/cm2•h and its absorption can be tuned from UV light to visible light by adjusting [Zn]/[Ag] ratio. In this study, we further extended the investigation, changed the amount of indium in a series of solid solutions, and increased the photochemical activity substantially. With little adjustment of the ratios of [In]/[Ag], the hydrogen production rate of the photocatalysts, (Ag-In-Zn)S, are significantly improved. The most enhancement of the activity can go up to three times, compared to the photocatalyst of [In]/[Ag]=1. SEM images show that different amount of nanosteps on the surface related to the ratios of [In]/[Ag]. These edges of nanosteps are considered as the active sites that facilitates the electron-hole separation, leading to higher solar-to-fuel conversion efficiency. The other ingredient, zinc, is used to control the band gap. With both variations in indium and zinc, the highest efficiency of this photocatalyst is 17.26 µmol/cm2•h. According to reaction kinetics, the water splitting reaction rate increases with temperature. In a separate experiment, the photocatalystic reactions were carried out at elevated temperatures. The absorption of core-shell nanoparticles (Ag@Au) can be adjusted systematically from visible light to IR range by altering the thickness of nanoshell (Au). The nanoparticles have an absorption edge in the IR range (>700 nm), which can convert the solar energy to heat. This unique property provides us a way to further utilize solar energy in the system of our visible-light-driven photocatalysts. However, the broad absorption of core-shell also covered the visible-light region, which decrease the efficiency of the metal sulfide photocatalysts. If the core-shell nanoparticles can be covered with (Ag-In-Zn)S solid solution, the efficiency of hydrogen production will be further raised in the future.
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Kai-WeiChou and 周楷崴. "Growth and Visible Light Photodetection of Indium doped Zinc Sulfide Nanomaterials." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/w4mnn7.
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Wang, Yi-Ping, and 王逸平. "Crystal Growth and Characterization of III-VI Indium Sulfide Compound Semiconductors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/62102442726197949970.
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博士國立臺灣科技大學
電子工程系
101
III-VI indium sulfide compound semiconductors have been grown by chemical vapor transport (CVT) method using ICl3 as a transport agent. The physical vapor transport (PVT) method was also used. Detailed characterization of the materials were carried out by using X-ray diffraction, Raman scattering, absorption, modulation reflectance, photoluminescence (PL), surface photoresponse (SPR) and photoconductivity (PC) techniques. X-ray analysis confirms that In2S3 crystal is of β phase tetragonal structure, while In6S7 crystal is monoclinic. Raman measurement reveals that InS crystallizes in orthorhombic structure with space group D122h. Optical property of InS, β-In2S3 and In6S7 was characterized using thermalreflectance (TR), piezoreflectance (PzR) and absorption measurements, which showed that InS is an indirect semiconductor, and those of β-In2S3 and In6S7 are direct semiconductors. The band gaps of InS, β-In2S3 and In6S7 at 300 K are determined to be 1.85 eV, 1.935 eV and 0.93 eV, respectively. For β-In2S3, the PC and SPR measurements have indicated not only the band-edge transitions but also transition features below and above the band edge. The below band-edge transition can be ascribed to the present of defect states. The defect and above-band-edge transition emissions of β-In2S3 crystal were characterized experimentally by PL measurements. Optical evidence of band gap, band-edge exciton, and white-light photoelectric conversion for the solar-energy material In6S7 has been demonstrated. The room temperature direct gap of In6S7 at 0.93 eV is extremely suitable for absorption of full sunlight spectrum extension to the near infrared region. The optical properties of InS were also examined. The band-edge was evaluated and identified using PzR and absorption measurements. Absorption measurement indicated indirect semiconducting nature for InS with a room temperature indirect band gap of 1.85 eV. The room temperature direct band gap of InS was determined to be 2.42 eV by the PzR measurement. In this study, we have demonstrated the ability to synthesize In-S compound semiconductors either in the forms of indirect band gap orthorhombic InS or direct band gap tetragonal β-In2S3 or direct band gap monoclinic In6S7 by using different growth conditions and stoichiometry in the system. These material systems have exhibited quite different structural and optical characters. From the experimental observations, band diagrams for the as-grown InS, β-In2S3 and In6S7 were constructed and presented.
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Chang, Yuang-Wei, and 張元瑋. "Nano-Structured Indium Sulfide on the Textured Silicon Hetero-Structure Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/hjxg7a.
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碩士國立虎尾科技大學
光電與材料科技研究所
100
Indium sulfide is a III-VI compound semiconductor，the indium sulfide are another attention to substitute to CdS buffer layer of thin films materials. Presently，A wide range of process have been applied to development In2S3 buffer layer，and to produce CIGS solar cells. In this treatise are discussing silicon and different texture by dry-etch and structure are Al / ITO /β-In2S3 (n-Type) / Si / Al，Then we will divided into three part to discuss：First part，we will fixed the texture times by the machine of STS. Then we will know which is roughening sample and bester. The 20 minute roughening samples are bester and efficiency. By the second part， According to first part to know 20 minute roughening are bester，So that we will fix on the times，change the different gold thickness be knowing which is bester and efficiency. The structure（AZO /β-In2S3 / Si）is a heterojunction solar cells. by the third part，We will studyed the powders that is photoluminescence by chemical bath deposition method to get that，and add Cerium(III) nitrate hexahydrate， to get a new one photoluminescence on the application.
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Ke, Wen Jie, and 柯文傑. "A study of the growth mechanism for indium sulfide nanocrystals from solvothermal synthesis." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/61989512998177423300.
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碩士長庚大學
化工與材料工程研究所
97
In this study, ultrathin hexagonal β-In2S3 nanoplates were synthesized using simple solvothermal route. The crystal phase, morphology and composition of as-prepared samples were characterized using x-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive analysis of X-ray (EDAX), respectively. Experimental data revealed that the as-synthesized sample are cubic β-In2S3 phase with preferential growth along the <220> direction. Shape of β-In2S3 nanocrystals depended on the components and the concentrations of the surfactants. Average particle size can be controlled between 40 nm and 1 μm by adjusting the reaction time and temperatures. The surface morphology of photoelectrode prepared from β-In2S3 nanocrystals affects the photoelectrochemical performance. The maximum photocurrent density reached 2.9 mA/cm2 with an external potential of 0V vs. SCE in 0.35 M sodium sulfide and 0.25 M potassium sulfite solutions under illumination using a Xe lamp at light intensity of 100 mW/cm2.
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Liu, Bei-Yuan, and 劉倍源. "Effects of sulfide treatment on interfacial properties of indium tin oxide/conducting polymer." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/84719545112559367177.
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碩士國立彰化師範大學
物理學系
98
In this study, the effect of sulfide treatment on the electrical and optical properties of the indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS)-based devices were researched. In this experiment, the elemental composition and elemental bonding of ITO with and without sulfide treatment were measured by X-ray photoelectron spectroscopy, the current-voltage (I-V) characteristics of ITO/PEDOT:PSS-based devices were measured by Keithley Model-4200, the optical properties of ITO were measured by ultraviolet-visible spectroscopy (UV-Vis). The experiment exhibited that (NH4)2Sx treatment could result in suppressing the hysteresis-type current-voltage characteristics, owing to the improvement in the interfacial stability of the ITO/PEDOT:PSS electrodes and a reduction in the interface trap-states related charge store at the ITO/PEDOT:PSS interface. This implies that the ITO/PEDOT:PSS electrodes fabricated using the (NH4)2Sx- treated ITO may produce a higher extraction efficiency for ITO/ PEDOT:PSS-based optoelectronic devices.
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Lee, Chi-Feng, and 李其峰. "The Effects of Indium Sulfide Deposition on B-doped TiO2 Dye-Sensitized Solar Cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/12782120763963543107.
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碩士國立交通大學
應用化學系碩博士班
100
The objective of this work is to optimize the thickness of TiO2 layer with boron doping and to study the effect of indium sulfide prepared by MOCVD on the efficiency of the N3 dye sensitized solar cell. The EDS and XRD analyses of the deposited indium sulfide show that it should be amorphous. The results indicate that the efficiency of the N3 DSSC can be enhanced from 5.46 % to 6.10 % by indium sulfide deposited on the TiO2 with 7 μm thickness. Using the best bare 10% boron doped TiO2.with 13 μm thickness, the enhancement by indium sulfide was found to increase from 6.73% to 7.04% for the N3 DSSC.
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"Biodegradation of indigo carmine and biosorption of sulphur black dye." Chinese University of Hong Kong, 1993. http://library.cuhk.edu.hk/record=b5889063.
Full textAbstract:
by Siu-tai Tsim.Thesis (M.Phil.)--Chinese University of Hong Kong, 1993.
Includes bibliographical references (leaves 382-403).
Statement --- p.4
Acknowledgements --- p.5
Abstract --- p.6
Abbreviation --- p.8
Chapter Chapter 1. --- General introduction --- p.10
Chapter PART I. --- Biodegradation of Indigo carmine
Chapter Chapter 2. --- Introduction to indigo/indigo carmine --- p.29
Chapter Chapter 3. --- Purification and characterization of crude indigo carmine degrading enzyme --- p.59
Chapter Chapter 4. --- Characterization of indigo carmine degradation products --- p.181
Chapter Chapter 5. --- Toxicity of indigo carmine and its degradation products --- p.219
Chapter Chapter 6. --- A new method to determine the concentration of indigo dye --- p.301
Chapter PART II. --- Biosorption of Sulfur black dye
Chapter Chapter 7. --- "An efficient method for removal of sulfur black dye, a contaminant in sodium thiosulfate, a side product of sulfur black production" --- p.319
References --- p.382
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Lin, Pei-yu, and 林佩玉. "Deposition of Copper Indium Sulfide on TiO2 Nanotube Arrays for the Photocatalytic Degradation of IPA in Air Streams." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/wtmvv7.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
100
TiO2 nanotube arrays were fabricated in ethylene glycol containing NH4F and water by anodization process under various conditions. TiO2 nanotube arrays were analyzed by field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction spectra, Potentiostat/Galvanostat, and photoluminescence spectroscopy in order to investigate characterization of TiO2 nanotube arrays. Effects of electrolyte temperature and water content of electrolyte on morphology and formation mechanism of TiO2 nanotube arrays were investigated. The experiment results demonstrate that TiO2 nanotube arrays with longer lengths, larger inner diameters, and thinner wall thicknesses could be fabricated in electrolytes of higher temperature, indicating that the limiting factor for growth of TiO2 nanotube arrays is the diffusion of reactants (oxygen-containing anionic species, fluorine ions) into the tubes or products ( [TiF6]2- ) away from the tubes. The experiment results also suggest that the appearance of “hazy layer” on the top of TiO2 nanotube arrays could be avoided by anodizing at lower temperatures. With the presence of higher water contents, the relatively fast chemical dissolution rate dominates the reaction because a larger amount of H+ ions are created, resulting in TiO2 nanotube arrays with larger inner diameters and shorter tube lengths. Strctures (tube length and inner diameter) of TiO2 nanotube arrays were controlled by adjusting anodization time and water content in anodization process. The experimental results show that experiments using TiO2 nanotube arrays with longer tube lengths and smaller inner diameters achieved higher photocatalytic performance. However, the photocatalytic activity of TiO2 nanotube arrays is after all limited by the penetration of illumination. From the PL analysis results of the prepared TiO2 nanotube arrays, bulk recombination is expected to be reduced as wall thickness become thinner, and the photoconversion efficiency is also expected to be enhanced. TiO2 nanotube arrays were modified with copper indium sulfide by successive ionic layer adsorption and reaction (SILAR) method. The modified TiO2 nanotube arrays were mainly analyzed by X-ray photoelectron spectroscopy and Potentiostat/Galvanostat to investigate their characterization. In the study, the XPS analysis results demonstrate the presence of copper indium sulfide thin film could only be observed on TiO2 nanotube arrays before the modified TiO2 nanotube arrays were annealed. TiO2 nanotube arrays were modified with copper indium sulfide by SILAR method resulting in some deviation on the molecularity and stoichiometry of copper indium sulfide, which affects the electrical property of the modified TiO2 nanotube arrays. Typically, In-rich copper indium sulfide thin films could be obtained by using lower sulfur precursor concentrations in SILAR method and the deposited films belonged to n-type semiconductor; the p-type Cu-rich copper indium sulfide thin films could be prepared by using higher sulfur precursor concentrations in SILAR method. When the chemical composition of Cu, In, and S is closer to the stoichiometric composition of copper indium sulfide (1:1:2), the modified TiO2 nanotube arrays exhibit higher photocatalytic performance for degrading gaseous IPA. Moreover, the modified TiO2 nanotube arrays show excellent stability during the photocatalytic process.
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Hauschild, Dirk. "Electron and soft x-ray spectroscopy of indium sulfide buffer layers and the interfaces in Cu(In,Ga)(S,Se)2-based thin-film solar cells." Doctoral thesis, 2015. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-126766.
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In this thesis, thin-film solar cells on the basis of Cu(In,Ga)(S,Se)2 (CIGSSe) were investigated. Until today, most high efficient CIGSSe-based solar cells use a toxic and wetchemical deposited CdS buffer layer, which doesn’t allow a dry inline production. However, a promising and well-performing alternative buffer layer, namely indium sulfide, has been found which doesn’t comprise these disadvantages. In order to shed light on these well-performing devices, the surfaces and in particular the interfaces which play a major role for the charge carrier transport are investigated in the framework of this thesis. Both, the chemical and electronic properties of the solar cells’ interfaces were characterized. In case of the physical vapor deposition of an InxSy-based buffer layer, the cleaning step of the CdS chemical-bath deposition is not present and thus changes of the absorber surface have to be taken into account. Therefore, adsorbate formation, oxidation, and segregation of absorber elements in dependence of the storing temperature and the humidity are investigated in the first part of this thesis. The efficiencies of CIGSSe-based solar cells with an InxSy buffer layer depend on the nominal indium concentration x and display a maximum for x = 42 %. In this thesis, InxSy samples with a nominal indium concentration of 40.2% ≤ x ≤ 43.2% were investigated by surface-sensitive and surface-near bulk-sensitive techniques, namely with photoemission spectroscopy (PES) and x-ray emission spectroscopy (XES). The surfaces of the films were found to be sulfur-poor and indium-rich in comparison with stoichiometric In2S3. Moreover, a direct determination of the band alignment at the InxSy/CISSe interface in dependence of the nominal indium concentration x was conducted with the help of PES and inverse PES (IPES) and a flat band alignment was found for x = 42 %. In order to study the impact of a heat treatment as it occurs during subsequent cell process steps, the indium sulfide-buffered absorbers were annealed for 30 minutes under UHV conditions at 200 °C after the initial data set was taken. Besides a reported enhanced solar cell performance, a significant copper diffusion from the absorber into the buffer layer takes place due to the thermal treatment. Accordingly, the impact of the copper diffusion on the hidden InxSy/CISSe interface was discussed and for x = 40.2% a significant cliff (downwards step in the conduction band) is observed. For increasing x, the alignment in the conduction band turns into a small upwards step (spike) for the region 41% ≤ x ≤ 43.2%. This explains the optimal solar cell performance for this indium contents. In a further step, the sodium-doped indium sulfide buffer which leads to significantly higher efficient solar cells was investigated. It was demonstrated by PES/IPES that the enhanced performance can be ascribed to a significant larger surface band gap in comparison with undoped InxSy. The occurring spike in the Na:InxSy/CISSe band alignment gets reduced due to a Se diffusion induced by the thermal treatment. Furthermore, after the thermal treatment the sodium doped indium sulfide layer experiences a copper diffusion which is reduced by more than a factor of two compared to pure InxSy. Next, the interface between the Na:InxSy buffer layer and the i-ZnO (i = intrinsic, non-deliberately doped), as a part of the transparent front contact was analyzed. The i-ZnO/Na:InxSy interface shows significant interdiffusion, leading to the formation of, e.g., ZnS and hence to a reduction of the nominal cliff in the conduction band alignment. In the last part of this thesis, the well-established surface-sensitive reflective electron energy loss spectroscopy (REELS) was utilized to study the CIGSSe absorber, the InxSy buffer, and annealed InxSy buffer surfaces. By fitting the characteristic inelastic scattering cross sections λK(E) with Drude-Lindhard oscillators the dielectric function was identified. The determined dielectric functions are in good agreement with values from bulk-sensitive optical measurements on indium sulfide layers. In contrast, for the chalcopyrite-based absorber significant differences appear. In particular, a substantial larger surface band gap of the CIGSSe surface of E^Ex_Gap = (1.4±0.2) eV in comparison with bulk values is determined. This provides for the first time an independent verification of earlier PES/IPES results. Finally, the electrons’ inelastic mean free paths l for the three investigated surfaces are compared for different primary energies with theoretical values and the universal curveDie vorliegende Arbeit untersucht Dünnschichtsolarzellen auf Basis von Cu(In,Ga)(S,Se)2 (CIGSSe). Um hohe Effizienzen bei CIGSSe-basierten Solarzellen zu erreichen, wurde bisher meist eine toxische und schlecht in einen Vakuumprozess integrierbare nasschemische CdS Pufferschicht verwendet. Mit Indiumsulfid konnte stattdessen eine vielversprechende alternative Pufferschicht gefunden werden, die diese nachteiligen Eigenschaften von CdS nicht aufweist und Solarzellen mit diesem Puffermaterial zeigen gute bis sehr gute Wirkungsgrade. Um die Ursachen der guten Leistungen herauszufinden, wurden die in der Solarzelle vorkommenden Oberflächen und Grenzflächen, die für den Ladungstransport eine zentrale Rolle spielen, Schritt für Schritt als Modellsysteme charakterisiert. Für einen InxSy-basierten Puffer, der durch die physikalische Gasphasenabscheidung aufgebracht wird, fehlt der Reinigungsprozess der Absorberoberflächen durch die nasschemische CdS Abscheidetechnik. Deshalb müssen Adsorbatbildung, Oxidation und Segregation von Absorberelementen die innerhalb der ersten Tage nach der Herstellung auftreten (je nach Feuchtigkeitsgehalt und Temperatur der Umgebung) berücksichtigt werden. Im ersten Teil der Arbeit werden solche Einflüsse auf die Oberfläche des Absorbers untersucht. Zellen mit einem Indiumsulfidpuffer zeigen Wirkungsgrade, die von der nominellen Indiumkonzentration x abhängen und bei x = 42% ein Optimum aufweisen. Eine stöchiometrische Analyse der InxSy Oberflächen ergab für 40.2% ≤ x ≤ 43.2% eine schwefelarme bzw. indiumreiche Oberfläche im Vergleich zu stöchiometrischem In2S3 (40% In und 60% S). Allerdings zeigen die untersuchten Proben für verschiedene Indiumkonzentrationen im Rahmen der oberflächensensitiven Photoemission (PES) und volumensensitiven Röntgenemission (XES) keine quantitativen Unterschiede. Mit Hilfe der PES und inversen PES (IPES) wurde der Bandverlauf an der InxSy/CISSe Grenzfläche in Abhängigkeit von der Indiumkonzentration untersucht und für x = 42% konnte ein flacher Bandverlauf ermittelt werden. Um den Einfluss des im Herstellungsprozess vorkommenden Temperaturschritts zu untersuchen, wurden die Proben für 30 Minuten auf 200 °C geheizt. Dabei konnte eine signifikante Diffusion von Kupfer aus dem Absorber in den Puffer beobachtet werden. Der Temperaturschritt führt neben der bereits bekannten Effizienzerhöhung vor allem zu einer Verringerung der Bandlücke des Puffers. Der Einfluss der Kupferdiffusion auf die verborgene InxSy/CISSe Grenzfläche wurde analysiert und für x = 40:2% wurde ein deutlicher "Cliff" (Stufe im Leitungsband nach unten) gefunden. Für Indiumkonzentrationen 41% ≤ x ≤ 43.2% wurde ein kleiner "Spike" (Stufe im Leitungsband nach oben) identifiziert, was dabei im Einklang mit den optimalen Wirkungsgraden ist. In einem weiteren Schritt wurde ein mit Natrium dotierter Indiumsulfidpuffer Na:InxSy, der verbesserte Wirkungsgrade zeigt, untersucht. Diese konnte zum einen auf eine deutlich vergrößerte Oberflächenbandlücke des Puffers zurückgeführt werden. Zum anderen wurde nach dem Temperaturschritt im Vergleich zu dem InxSy Puffer eine um den Faktor zwei verringerte Kupferdiffusion an der Oberfläche festgestellt. Des Weiteren konnte bei dem Temperaturschritt eine Diffusion von Selen festgestellt werden, die den vor dem Temperaturschritt vorhandenen "Spike" im Leitungsbandverlauf verringert. Nach dem Aufbringen der i-ZnO Schicht (i = intrinsisch, nicht absichtlich dotiert) als Teil des Frontkontakts auf den Na:InxSy Puffer, wurden Durchmischungseffekte an der i-ZnO/Na:InxSy Grenzfläche gefunden. Im weiteren Verlauf zeigte sich, dass der nominell auftretende "Cliff" zwischen i-ZnO und Na:InxSy durch die Bildung von ZnS reduziert bzw. vernachlässigt werden kann. Im letzten Teil der Arbeit wurde die etablierte oberflächensensitive reflektive Elektronenenergieverlustspektroskopie auf die Absorber- sowie Indiumsulfidoberflächen angewandt. Die ermittelten inelastisch gestreuten Verlustspektren λK(E) wurden mit dem Drude-Lindhard Modell simuliert und somit die dielektrische Funktion der jeweiligen Oberflächen bestimmt. Ein Vergleich mit volumensensitiven optischen Werten zeigt für die InxSy Schichten eine gute Übereinstimmung. Bei der CIGSSe Oberfläche konnten hingegen signifikante Unterschiede festgestellt werden. Dabei wurde erstmals die Oberflächenbandlücke eines Cu(In,Ga)(S,Se)2 Absorbers unabhängig von PES/IPES zu E^Ex_Gap = (1.4 ±0.2) eV verifiziert. Abschließend wurden die mittleren freien Weglängen der Elektronen l für die drei untersuchten Oberflächen für unterschiedliche Energien mit theoretischen Werten und der universellen Kurve verglichen
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Laplante, Patrick. "Caractérisation de l'effet fibroprolifératif induit par la libération paracrine de peptides issus de l'apoptose endothéliale." Thèse, 2004. http://hdl.handle.net/1866/15535.
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Grenier, Patrick. "Étude de l'effet d'inhibition du gel induit par les sulfates dans les nuages arctiques à l'aide des mesures satellitaires de CloudSat et CALIPSO." Thèse, 2010. http://www.archipel.uqam.ca/3790/1/D1968.pdf.
Full textAbstract:
Les sulfates issus de la pollution industrielle d'Eurasie et transportés à travers la basse troposphère arctique durant l'hiver sont soupçonnés d'altérer les propriétés des nuages au point d'affecter significativement le climat de cette région. Un de leurs effets potentiellement importants est l'inhibition du gel des gouttelettes en cristaux de glace (effet IGIS), qui favoriserait les nuages formés de cristaux à grande taille et déclencherait un mécanisme associé à une anomalie de refroidissement à la surface. Grâce à de récentes données satellitaires, issues des missions CloudSat et CALIPSO, les implications escomptées de l'effet IGIS peuvent être testées à l'échelle de l'Arctique. La superposition des observations quasi-simultanées du radar de CloudSat et du lidar de CALIPSO a permis de développer une nouvelle classification des nuages arctiques centrée sur le rayon effectif des cristaux de glace. Un proxy de la concentration en sulfates dans les parcelles d'air non-nuageuses a aussi été élaboré à partir des mesures du lidar, et validé à partir de mesures in situ. Différents tests de corrélation entre d'une part les propriétés des nuages glacés censés êtres les plus affectés par l'effet IGIS (nommés TIC-2B) et d'autre part le proxy de la concentration en sulfates ont été conduits afin d'approfondir notre compréhension de cet effet. Des limites méthodologiques, entre autres l'impossibilité d'estimer les concentrations en sulfates à l'intérieur des nuages, ont empêché l'atteinte de conclusions définitives. Cependant, les distributions géographiques des TIC-2B el du proxy sont cohérentes avec un effet IGIS ayant lieu durant le transport de la pollution eurasienne vers les mers de Chukchi et de Beaufort. Enfin, les propriétés macrophysiques des nuages stratiformes en phase mixte, potentiellement affectés eux aussi par l'effet IGIS, ont été caractérisées.
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MOTS-CLÉS DE L’AUTEUR : climat arctique, sulfates, nuages, effet indirect des aérosols, données satellitaires.
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Kastner, Miriam, Arthur J. Spivack, Marta Torres, Evan A. Solomon, D. V. Borole, Gretchen Robertson, and Hamendra C. Das. "GAS HYDRATES IN THREE INDIAN OCEAN REGIONS, A COMPARATIVE STUDY OF OCCURRENCE AND SUBSURFACE HYDROLOGY." 2008. http://hdl.handle.net/2429/2712.
Full textAbstract:
To establish the structural and lithological controls on gas hydrate distribution and to assess the potential energy resource and environmental hazards in the Indian Ocean, non-pressurized and pressurized cores were recovered from the Krishna-Godavari (K-G) and Mahanadi Basins offshore east India, and from an Andaman Sea site. The pore fluids were analyzed for: salinity, Cl-, sulfate, sulfide, carbonate alkalinity, Ca2+, Mg2+, Sr2+, K+, Na+, Ba2+, and Li+ concentrations, δ13C-DIC, δ18O, D/H, and 87Sr/86Sr ratios; together with infra-red imaging they provided important constraints on the presence and distribution of gas hydrates, thus on the subsurface hydrology. Evidence for methane hydrate was obtained at each of the sites. Only in the K-G Basin, between the sulfate-methane transition zone (SMT) depth and ~80 mbsf, higher than seawater chloride concentrations are observed; below this zone to the depth of the base of the gas hydrate zone (BGHSZ), chloride concentrations and salinity are lower than seawater value. In the Andaman Sea and Mahanadi Basin, only lower than seawater chloride concentrations are observed, and the shallowest gas hydrates occur at 100-200 m below the sulfate-methane transition zone (SMT) and extend to the depth of the BGHSZ. In the K-G Basin, the highest methane hydrate concentrations are associated with fracture zones in clay-rich sediments and/or in some coarser grained horizons. In the Andaman Sea, however, they are primarily associated with volcanic ash horizons. Assuming dilution by water released from dissociated methane hydrate, chloride and salinity anomalies suggest pore volume occupancies on the order of <1% to a maximum of ~61% at two sites (10, 21) in the K-G Basin and <1% to a maximum of ~76% at the Andaman Sea site. Overall, the percent pore volume occupancies based on pressure core methane concentrations and the chloride concentrations in conventional cores are similar.
Variations in sulfate gradients were observed with the steepest gradient having the SMT at 8 mbsf in the K-G Basin and the deepest SMT at ~25 mbsf at the Andaman Sea site. The extreme negative δ13C values of the dissolved inorganic carbon (DIC), ranging from -38‰ to -47‰ at the SMT at some of the sites, indicate that anaerobic oxidation of methane (AOM) is an important reaction responsible for sulfate reduction at these sites. At several sites in the K-G Basin, however, the δ13C-DIC values indicate that organic matter oxidation is the dominant reaction.
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Sunil, Maligi Anantha. "Studies on AgInS2 Films as Absorber Layer for Heterojunction Solar Cells." Thesis, 2016. http://etd.iisc.ernet.in/handle/2005/2818.
Full textAbstract:
Currently conventional sources like coal, petroleum and natural gas meet the energy requirements of developing and undeveloped countries. Over a period of time there is high risk of these energy sources getting depleted. Hence an alternate source of energy i.e. renewable energy is the need of the hour. The advantages of renewable energy like higher sustainability, lesser maintenance, low cost of operation, and minimal impact on the environment make the role of renewable energy sources significant. Out of the various renewable energy sources like solar energy, wind energy, hydropower, biogas, tidal and geothermal, usage of solar energy is gradually increasing. Among various solar energy sources, Photovoltaics has dominated over the past two decades since it is free clean energy and availability of abundant sunlight on earth.
Over the past few decades, thin film solar cells (TFSC) have gained considerable interest as an economically feasible alternative to conventional silicon (Si) photovoltaic devices. TFSCs have the potential to be as efficient as Si solar cells both in terms of conversion efficiency as well as cost. The advantages of TFSC are that they are easy to prepare, lesser thickness, requires lesser materials, light weight, low cost and opto-electronic properties can be tuned by varying the process parameters. The present study is focused on the fabrication of AgInS2/ZnS heterojunction thin film solar cell. AgInS2 absorber layer is deposited using both vacuum (sputtering/sulfurization) and non-vacuum (ultrasonic spray pyrolysis) techniques. ZnS window layer is prepared using thermal evaporation technique, detailed experimental investigation has been conducted and the results have been reported in this work. The thesis is divided into 6 chapters.
Chapter 1 gives general introduction about solar cells and working principle of solar cell. It also discusses thin film solar cell technology and its advantages. Layers of thin film solar cell structure, Significance of each layers and possible materials to be used are emphasized. A detailed overview of the available literature on both AgInS2 absorber layer and ZnS window layer has been presented. Based on the literature review, objectives of the present work are defined.
Chapter 2 explains the theory and experimental details of deposition techniques used for the growth of AgInS2 and ZnS films. Details of characterization techniques to study film properties are described in detail.
Chapter 3 presents a systematic study of AgInS2 thin films deposited by sulfurization of sputtered Ag-In metallic precursors. Initially, AgInS2 films are deposited by varying the substrate temperature and properties of as-deposited films are characterized. Structural, morphological, electrical and optical properties of AgInS2 films are explained. From these studies, samples with better properties at particular substrate temperature are optimized. By fixing the substrate temperature, deposition time of silver is varied by keeping other deposition conditions same and the properties of films are discussed. It was observed that deposition time of silver doesn’t have much impact on structural properties of AgInS2 films. However, opto-electric properties of AgInS2 films are enhanced. Based on characterization studies, deposition time of silver is optimized. Deposition time of indium is varied by keeping substrate temperature and silver deposition to optimized value. The properties of as-deposited films are discussed. Based on the above studies, the optimized p type films have a band gap of 1.64 eV, carrier concentration of 1013 ions/cm3 and Resistivity of order 103 Ω-cm.
Chapter 4 presents a systematic study of AgInS2 thin films deposited by ultrasonic spray pyrolysis. AgInS2 films are deposited by varying the substrate temperature and properties of as deposited films are characterized. Structural, morphological, electrical and optical properties of AgInS2 films are explained. From these studies, samples with better properties at particular substrate temperature are optimized. By fixing the substrate temperature, concentration of silver molarity in the precursor solution is varied by keeping other deposition conditions same and the properties of films are discussed. Structural, optical and electrical properties of AgInS2 films are
enhanced with the increase in silver concentration. Based on characterization studies, concentration of silver is optimized. Similarly concentration of indium molarity in the precursor solution is varied and the properties of as-deposited films are discussed. Finally, sulfur molarity in the precursor solution is varied and properties of films are discussed. It was observed that increasing sulfur after certain limit does not have any effect on the properties of the films. Based
on the above studies, this method resulted in the films with resistivity of 103 Ω-cm and band gap of 1.64 eV. These films showed a carrier concentration of 1013 ions/cm3.
Chapter 5 describes the growth of ZnS films using thermal evaporation technique. Influence of thickness on the properties of ZnS films is explained. Samples with good crystallinity, high transmission, and wider gap are selected for device fabrication. This p type layer showed a band gap of 3.52 eV. Solar cells have been fabricated using the AgInS2 films developed by both sputtering and ultrasonic spray pyrolysis techniques. A maximum cell efficiency of 0.92 percent has been achieved for the cell with 0.950 µm thick sputtered AgInS2 layer and thermally evaporated 42 nm thick ZnS layer. In comparison, the ultrasonic spray pyrolysis deposited films gave an efficiency of 0.54 percent. These values are comparable to those mentioned in a couple of reports earlier.
Chapter 6 summarizes the conclusions drawn from the present investigations and scope of future work is suggested.
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Maity, Mitasree. "Bile Acid based Supramolecular Gels, Soft Hybrid Materials and their Applications." Thesis, 2016. http://hdl.handle.net/2005/2928.
Full textAbstract:
Chapter 1. Supramolecular Gels and their Applications
Supramolecular gels are viscoelastic materials composed of a solid like three dimensional fibrillary network that is embedded in a liquid. Supramolecular gels are derived from low molecular weight compounds (typically MW < 3000). In the 1990s, the investigations on gels were mainly focused on designing new gelator molecules. However, during the last decade, research focus shifted towards designing functional gels and their applications. As a result of extensive work in this area, gels have been found to have varied applications in the templated synthesis of inorganic nanomaterials, hybrid materials, light harvesting systems, as responsive system and sensors, and also in drug delivery, tissue engineering etc. This chapter gives an introduction to supramolecular hydrogels/organogels and relevant bile acid chemistry touching upon the gelation properties of the bile acid derivatives. Diverse applications of the supramolecular gels are also illustrated with several examples.
Scheme 1. Various applications of functional supramolecular gels
Chapter 2. Bile Acid derived novel Hydrogelators
Part 1. Hydrogelation of Bile acid protected Amino acids and Hybrid Materials
Hydrogels from low molecular weight molecules have significant importance in biomedical applications. In this chapter, we report injectable hydrogel formation from bile acid conjugates of various amino acids. Hydrogel formation was found to be dependent on multiple factors such as bile acid backbone structure, linkage between the bile acid and the amino acid, pH etc. Single crystal structures of lithocholyl phenylalanine, lithocholyl-glycine, lithocholyl-L valine and lithocholyl-L alanine were also determined. Finally, the hydrogel frameworks were utilized to produce hybrid materials with Gold and ZnO nanoparticles.
Scheme 2. (a) Crystal structure of LC-LF-OH gelator molecule, (b) photograph of gel, (c) SEM and (d) AFM image of LC-LF-OH xerogel
Part 2. Hydrogelation of bile acid-dipeptide conjugates and in situ synthesis
of silver and gold nanoparticles in the hydrogel matrix
Fabricating supramolecular hydrogels with embedded metal nanostructures are important for the design of novel hybrid nanocomposite materials for diverse applications such as bio sensing and chemo sensing platforms, catalytic and antibacterial functional materials etc. Supramolecular self-assembly of bile acid-dipeptide conjugates have led to the formation of new supramolecular hydrogels. Gelation of these molecules depends strongly on the hydrophobic character of the bile acids. Ag+ and Au3+ salts were incorporated in the hydrogels, and photo reduction and chemical reduction led to the in situ generation of Ag and Au NPs in these supramolecular hydrogels without the addition of any external stabilizing agent. The color, size and shape of silver nanoparticles formed by photo reduction depended on the amino acid residue on the side chain. Furthermore, the hydrogel-Ag nanocomposite was tested for its antimicrobial activity.
Scheme 3. Bile acid based dipeptide hydrogelators and soft hybrid materials
Chapter 3. Sonogels of bile salts of In(III): use in the formation of self-templated indium sulfide nanostructures
In this chapter, facile hydrogel formation by Indium(III) cholate and deoxy cholate are reported. When In(III) solution was added to aqueous solutions of sodium cholate and sodium deoxy cholate and sonicated, the mixtures formed gels. The gels thus obtained were translucent/turbid and thermos irreversible. Rheological measurements showed that all of them could be classified as viscoelastic soft solids. Scanning electron microscopy and atomic force microscopy showed typical entangled three dimensional fibrous networks. The In-Ch hydrogel were further used to prepare nanostructured In2S3 in which the cholate units possibly acted as a surfactant to confine the growth of the Nano flakes.
Scheme 4. In-Ch hydrogel (Photograph and SEM image of In-Ch gel)
Chapter 4. Palladium-Hydrogel Nanocomposite for C-C Coupling Reactions
Supported metallic nanoparticles are important composite materials owing to their enormous potential for applications in various fields. This chapter describes the in situ formation of palladium nanoparticles in a calcium-cholate (Ca-Ch) hydrogel by reduction with sodium cyan borohydride. The hydrogel matrix appeared to assist the controlled growth as well as stabilization of palladium nanoparticles. The palladium nanoparticle/Ca-Ch hydrogel hybrid
was characterized by scanning and transmission electron microscopy, atomic force microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. Furthermore, PdNP/Ca-Ch hybrid xerogel was shown to act as an active catalyst for Suzuki reaction under aqueous aerobic conditions, up to 4 cycles. This PdNP/Ca-Ch xerogel retained its catalytic activities on storage for several months.
Scheme 5. Palladium-hydrogel nanocomposite for C-C coupling reactions in water
Chapter 5. Sensitization of Terbium/Europium in self-assembled cholate hydrogel: An approach towards the detection of amine vapours "Luminescent" lanthanides have intrinsic low molar absorptivity, although this problem can be addressed by complexing the lanthanide ion with suitable chelating ligands which improve the luminescence properties drastically. However the design of such systems often involves careful planning and laborious synthetic steps. It is therefore desirable to have a simpler way to sensitize lanthanides with high efficiency.
It was observed in our group that trivalent lanthanides formed hydrogels on the addition of sodium cholate. This chapter describes the discovery of the several biphenyl derivatives (such as 4-biphenylcarbaxaldehyde, 4-acetylbiphenyl) for sensitization of Tb(III) and Eu(III) in lanthanide hydrogels. Sensitization of Tb(III) and Eu(III) were observed by doping was characterized by scanning and transmission electron microscopy, atomic force microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. Furthermore, PdNP/Ca-Ch hybrid xerogel was shown to act as an active catalyst for Suzuki reaction under aqueous aerobic conditions, up to 4 cycles. This PdNP/Ca-Ch xerogel retained its catalytic activities on storage for several months.
Scheme 6. Schematic representation of the sensitization process (the arrangement of themolecules in the gel fiber is arbitrary)(For figures pl refer the abstract pdf file)