Дисертації з теми "Zn(S,O,OH)"
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Moura, Alysson Elson Galv?o de. "S?ntese, sinteriza??o e caracteriza??o de ferritas ? base de Ni-Zn." Universidade Federal do Rio Grande do Norte, 2008. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17599.
Анотація:
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Previous issue date: 2008-09-24Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Were synthesized different ferrites NixZn1-xFe2O4 (0,4 ≤ x ≤ 0,6) compositions by using citrate precursor method. Initially, the precursors citrates of iron, nickel and zinc were mixed and homogenized. The stoichiometric compositions were calcined at 350?C without atmosphere control and the calcined powders were pressed in pellets and toroids. The pressed material was sintered from 1100? up to 1200?C in argon atmosphere. The calcined powders were characterized by XRD, TGA/DTG, FTIR, SEM and vibrating sample magnetometer (VSM). All sintered samples were characterized using XRD, SEM, VSM and measurements of magnetic permeability and loss factor were obtained. It was formed pure ferromagnetic phase at all used temperatures. The Rietveld analyses allowed to calculate the cations level occupation and the crystallite size. The analyses obtained nanometric crystals (12-20 nm) to the calcined powder. By SEM, the sintered samples shows grains sizes from 1 to 10 μm. Sintered densities (ρ) were measured by the Archimedes method and with increasing Zn content, the bulk density decrease. The better magnetization results (105-110 emu/g) were obtained for x=0,6 at all sintering temperatures. The hysteresis shows characteristics of soft magnetic material. Two magnetization processes were considered, superparamagnetism at low temperature and the magnetic domains formation at high temperatures. The sintered toroids presents relative magnetic permeability (μr) from 7 to 32 and loss factor (tanδ) of about 1. The frequency response of toroids range from 0,3 kHz to 0,2 GHz. The composition x=0,5 presents both greater μr and tanδ values and x=0,6 the most broad range of frequency response. Various microstructural factors show influence on the behavior of μr and tanδ, such as: grain size, porosity across grain boundary and inside the grain, grain boundary content and domain walls movement during the process of magnetization at high frequency studies (0,3kKz 0,2 GHz)
Foram sintetizadas diferentes composi??es da ferrita Ni1-xZnxFe2O4 com 0,4 ≤ x ≤ 0,6 pelo uso do m?todo dos citratos precursores. Para se obter a fase estequiom?trica do sistema Ni1-xZnxFe2O4 foram misturados e homogeneizados os citratos precursores de ferro, n?quel e zinco. As composi??es estequiom?tricas foram calcinadas em atmosfera ambiente na temperatura de 350?C e depois prensadas em pastilhas e tor?ides. As amostras prensadas foram sinterizadas nas temperaturas de 1100?, 1150? e 1200?C em atmosfera de arg?nio. Os p?s calcinados foram caracterizados por DRX, TGA/DTG, FTIR, MEV e magnetometria de amostra vibrante (MAV) e as amostras sinterizadas por DRX, MEV, MAV, massa espec?fica e medidas de permeabilidade e perdas magn?ticas. Observou-se a forma??o de fase pura ferrimagn?tica em todas as temperaturas aplicadas. A an?lise pelo m?todo de Rietveld calculou o n?vel de ocupa??o dos c?tions e o tamanho de cristalito. Foram obtidos tamanhos de cristais nanom?tricos, de 12 a 20 nm para os p?s calcinados. Por MEV, as amostras sinterizadas apresentam tamanhos de gr?os na faixa de 1 a 10 μm. A massa espec?fica (ρ) do material sinterizado apresenta uma tend?ncia de diminui??o com a adi??o de Zn. Os melhores resultados de magnetiza??o foram obtidos para x=0,6 nas tr?s temperaturas de sinteriza??o, variando de 105 a 110 emu/g. As histereses mostram um perfil de materiais magn?ticos moles. Dois processos de magnetiza??o foram considerados, o superparamagnetismo a baixa temperatura (350?C) e a forma??o de dom?nios magn?ticos em altas temperaturas. Os materiais sinterizados apresentam permeabilidade (μ) de algumas unidades, de 7 a 30, e perdas magn?ticas (tanδ) por volta de 1. A resposta em freq??ncia dos n?cleos toroidais est? na faixa de 0,3 kHz a 0,2 GHz. Os maiores valores de μ e tanδ s?o para x=0,5 e a maior faixa de resposta em freq??ncia ? para x=0,6. V?rios fatores da microestrutura contribuem para o comportamento das grandezas μ e tanδ, tais como: os tamanhos dos gr?os, porosidade inter e intragranular, quantidade de contornos de gr?os e os aspectos da din?mica das paredes de dom?nios quando excitadas magneticamente sob alta freq??ncia
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Hultqvist, Adam. "Cadmium Free Buffer Layers and the Influence of their Material Properties on the Performance of Cu(In,Ga)Se2 Solar Cells." Doctoral thesis, Uppsala universitet, Fasta tillståndets elektronik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-133112.
Анотація:
CdS is conventionally used as a buffer layer in Cu(In,Ga)Se2, CIGS, solar cells. The aim of this thesis is to substitute CdS with cadmium-free, more transparent and environmentally benign alternative buffer layers and to analyze how the material properties of alternative layers affect the solar cell performance. The alternative buffer layers have been deposited using Atomic Layer Deposition, ALD. A theoretical explanation for the success of CdS is that its conduction band, Ec, forms a small positive offset with that of CIGS. In one of the studies in this thesis the theory is tested experimentally by changing both the Ec position of the CIGS and of Zn(O,S) buffer layers through changing their gallium and sulfur contents respectively. Surprisingly, the top performing solar cells for all gallium contents have Zn(O,S) buffer layers with the same sulfur content and properties in spite of predicted unfavorable Ec offsets. An explanation is proposed based on observed non-homogenous composition in the buffer layer. This thesis also shows that the solar cell performance is strongly related to the resistivity of alternative buffer layers made of (Zn,Mg)O. A tentative explanation is that a high resistivity reduces the influence of shunt paths at the buffer layer/absorber interface. For devices in operation however, it seems beneficial to induce persistent photoconductivity, by light soaking, which can reduce the effective Ec barrier at the interface and thereby improve the fill factor of the solar cells. Zn-Sn-O is introduced as a new buffer layer in this thesis. The initial studies show that solar cells with Zn-Sn-O buffer layers have comparable performance to the CdS reference devices. While an intrinsic ZnO layer is required for a high reproducibility and performance of solar cells with CdS buffer layers it is shown in this thesis that it can be thinned if Zn(O,S) or omitted if (Zn,Mg)O buffer layers are used instead. As a result, a top conversion efficiency of 18.1 % was achieved with an (Zn,Mg)O buffer layer, a record for a cadmium and sulfur free CIGS solar cell.Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 717
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Hora, Paulo Henrique Almeida da. "S?ntese, caracteriza??o, propriedades e aplica??o dos sistemas Mg- Al, Zn-Al e Mg-Fe." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17758.
Анотація:
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Previous issue date: 2014-01-24Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The Layered Double Hydroxides has become extremely promising materials due to its range of applications, easily obtained in the laboratory and reusability after calcination, so the knowledge regarding their properties is of utmost importance. In this study were synthesized layered double hydroxides of two systems, Mg-Al and Zn-Al, and such materials were analyzed with X-ray diffraction and, from these data, we determined the volume density, planar atomic density, size crystallite, lattice parameters, interplanar spacing and interlayer space available. Such materials were also subjected to thermogravimetric analysis reasons for heating 5, 10, 20 and 25 ? C / min to determine kinetic parameters for the formation of metaphases HTD and HTB based on theoretical models Ozawa, Flynn-Wall Starink and Model Free Kinetics. In addition, the layered double hydroxides synthesized in this working ratios were calcined heating 2.5 ? C / min and 20 ? C / min, and tested for adsorption of nitrate anion in aqueous solution batch system at time intervals 5 min, 15 min, 30 min, 1h, 2h and 4h. Such calcined materials were also subjected to exposure to the atmosphere and at intervals of 1 week, 2 weeks and 1 month were analyzed by infrared spectroscopy to study the kinetics of regeneration determining structural called "memory effect"
Os Hidr?xidos Duplos Lamelares tem se tornado materiais extremamente promissores devido a sua gama de aplica??es, f?cil obten??o em laborat?rio e a possibilidade de reutiliza??o ap?s calcina??o, portanto o conhecimento referente ? suas propriedades ? de extrema relev?ncia. Neste estudo foram sintetizados hidr?xidos duplos lamelares de dois sistemas, Mg-Al e Zn-Al, e tais materiais foram submetidos a an?lise com difra??o de raios X e, a partir de tais dados, foram determinados a densidade volum?trica, densidade at?mica planar, tamanho do cristalito, par?metros de rede cristalina, dist?ncia interplanar e espa?o interlamelar dispon?vel. Tais materiais tamb?m foram submetidos ? an?lise termogravim?trica em raz?es de aquecimento de 5, 10, 20 e 25 ?C/min para determina??o de par?metros cin?ticos durante a forma??o das metafases HTD e HTB com base nos modelos te?ricos de Ozawa, Flynn-Wall, Starink e Model Free Kinetics. Al?m disso, os hidr?xidos duplos lamelares sintetizados neste trabalhado foram calcinados em raz?es de aquecimento de 2,5 ?C/min e 20 ?C/min e submetidos a ensaios de adsor??o de ?nion nitrato em solu??o aquosa em sistema de batelada em intervalos de tempo de 5 min, 15 min, 30 min, 1h, 2h e 4h. Tais materiais calcinados tamb?m foram submetidos ? exposi??o com a atmosfera e em intervalos de tempo de 1 semana e 2 semanas foram analisados atrav?s de difra??o de raios X para estudo determina??o da cin?tica de regenera??o estrutural denominada efeito mem?ria
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Xavier, Camila Soares. "Estudo das propriedades fotoluminescentes de 'CA''ZN IND.2''(OH) IND.6'.2'H IND.2"O' obtidos a partir do método hidrometal-microondas /." Araraquara : [s.n.], 2010. http://hdl.handle.net/11449/105771.
Анотація:
Orientador: Elson Longo da SilvaBanca: Mário Cilense
Banca: Fenelon Martinho Lima Pontes
Banca: Máximo Siu Li
Banca: João Batista Baldo
Resumo: Neste trabalho, foi estudado a formação dos pós de hexahidroxodizincato de cálcio dihidratado, CaZn2(OH)6.2H2O (CZO) sobre condições hidrotermais-microondas (HM) e partindo de diferentes reagentes e surfactantes. Estes pós foram analisados por difração de raios X (DRX), microscopia eletrônica de varredura com canhão de elétrons por emissão de campo (FEG-MEV), espectroscopia de absorção na região do ultravioleta visível (UV-vis), espectroscopia na região do infravermelho (IV) e medidas de fotoluminescência (FL). Os padrões de DRX confirmaram que a fase CZO pura foi obtida após o processamento HM realizado a 130 ºC por 2 h com a síntese partindo de nitratos, enquanto que as demais apresentaram fases secundárias. As micrografias FEG-MEV indicaram que as modificações bem como o crescimento das micropartículas de CZO foram orientadas pelo mecanismo de coalescência e Ostwald-ripening. O espectro UV-vis ilustrou que este material tem um band gap óptico indireto. Os pós de CZO puros exibiram uma emissão amarela quando excitados por um comprimento de onda de 350 nm em temperatura ambiente, enquanto que os demais exibiram uma emissão na região do laranja
Abstract: In this work, it was studied the formation of calcium hexahydroxodizincate dehydrate, CaZn2(OH)6.2H2O (CZO) powders under microwave-hydrothermal (MH) conditions and using the different reagents and surfactants. These powders were analyzed by X-ray diffraction (XRD), Field-emission gum scanning electron microscopy (FEG-SEM), ultraviolet-visible (UV-vis) absorption spectroscopy, infra red spectroscopy (FTIR) and photoluminescence (PL) measurements. XRD patterns confirmed that the pure CZO phase was obtained after MH processing performed at 130 ºC for 2 h. FEG-SEM micrographs indicated that the morphological modifications as well as the growth of CZO microparticles are governed by Ostwal-ripening and coalescence mechanisms. UV-vis spectra showed that this material have an indirect optical band gap. The pure CZO powders exhibited an yellow PL emission when excited by 350 nm wavelength at room temperature, whereas the other powders exhibited the orange emission
Doutor
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Gomes, Kalyanne Keyly Pereira. "S?ntese e caracteriza??o de aluminofosfato impregnado com molibd?nio/zinco visando a dessulfuriza??o por adsor??o." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15910.
Анотація:
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Previous issue date: 2011-10-27Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Discussions about pollution caused by vehicles emission are old and have been developed along the years. The search for cleaner technologies and frequent weather alterations have been inducing industries and government organizations to impose limits much more rigorous to the contaminant content in fuels, which have an direct impact in atmospheric emissions. Nowadays, the quality of fuels, in relation to the sulfur content, is carried out through the process of hydrodesulfurization. Adsorption processes also represent an interesting alternative route to the removal of sulfur content. Both processes are simpler and operate to atmospheric temperatures and pressures. This work studies the synthesis and characterization of aluminophosphate impregnate with zinc, molybdenum or both, and its application in the sulfur removal from the gasoline through the adsorption process, using a pattern gasoline containing isooctane and thiophene. The adsorbents were characterized by x-ray diffraction, differential thermal analysis (DTG), x-ray fluorescence and scanning electron microscopy (SEM). The specific area, volume and pore diameter were determined by BET (Brunauer- Emmet-Teller) and the t-plot method. The sulfur was quantified by elementary analysis using ANTEK 9000 NS. The adsorption process was evaluated as function of the temperature variation and initial sulfur content through the adsorption isotherm and its thermodynamic parameters. The parameters of entropy (ΔS), enthalpy variation (ΔH) and free Gibbs energy (ΔG) were calculated through the graph ln(Kd) versus 1/T. Langmuir, Freundlich and Langmuir-Freundlich models were adjusted to the experimental data, and the last one had presented better results. The thermodynamic tests were accomplished in different temperatures, such as 30, 40 and 50?C, where it was concluded the adsorption process is spontaneous and exothermic. The kinetic of adsorption was studied by 24 h and it showed that the capability adsorption to the adsorbents studied respect the following order: MoZnPO > MoPO > ZnPO > AlPO. The maximum adsorption capacity was 4.91 mg/g for MoZnPO with an adsorption efficiency of 49%.
As discuss?es sobre o problema da polui??o causada por emiss?es veiculares s?o antigas e v?m evoluindo com o passar do tempo. A procura por tecnologias mais limpas e as altera??es clim?ticas cada vez mais frequentes induziram as ind?strias e os ?rg?os governamentais a impor limites cada vez mais rigorosos para os teores de contaminantes nos combust?veis, os quais impactam diretamente nas emiss?es atmosf?ricas. Atualmente a forma de melhorar a qualidade dos combust?veis, quanto ao enxofre, ? atrav?s do processo de hidrodessulfuriza??o e recentemente, os processos de adsor??o tem se mostrado como uma alternativa bastante interessante ? remo??o de enxofre, pois tais processos s?o mais simples e operam a temperaturas e press?es atmosf?ricas. O presente trabalho contempla a s?ntese e caracteriza??o do aluminofosfato impregnado com zinco, molibd?nio ou ambos e sua aplica??o no estudo da remo??o de enxofre da gasolina atrav?s do processo de adsor??o, utilizando uma gasolina modelo contendo iso-octano e tiofeno. Os adsorventes foram caracterizados por difra??o de raios-X, an?lise termogravim?trica (ATG), fluoresc?ncia de raios-X e microscopia eletr?nica de varredura (MEV). A ?rea espec?fica, volume e di?metro de poros foram determinados pelo m?todo BET (Brunauer-Emmet-Teller) e m?todo t-plot. O enxofre foi quantificado por analise elementar atrav?s do ANTEK 9000 NS. O Processo de adsor??o foi avaliado em fun??o da varia??o da temperatura e da concentra??o inicial de enxofre atrav?s das isotermas de adsor??o e de seus par?metros termodin?micos. Os par?metros varia??o de entropia (ΔS), varia??o de entalpia (ΔH) e varia??o da energia livre de Gibbs (ΔG) foram calculados pelo gr?fico de ln(K) versus 1/T. Os modelos de Langmuir, Freundlich e Langmuir-Freundlich foram ajustados aos dados experimentais, tendo o ?ltimo apresentado os melhores resultados. Os testes termodin?micos foram realizados nas temperaturas de 30, 40, 50 ?C e constatou-se que o processo de adsor??o ? espont?neo e exot?rmico. A cin?tica da adsor??o foi estudada por 24 horas e mostrou que a capacidade de adsor??o para os adsorventes estudados segue a seguinte ordem: MoZnPO > MoPO > ZnPO > AlPO. A capacidade m?xima de adsor??o foi 4,91 mg/g para o MoZnPO com uma efici?ncia de adsor??o de 49%.
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Platzer-Björkman, Charlotte. "Band Alignment Between ZnO-Based and Cu(In,Ga)Se2 Thin Films for High Efficiency Solar Cells." Doctoral thesis, Uppsala universitet, Fasta tillståndets elektronik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6263.
Анотація:
Thin-film solar cells based on Cu(In,Ga)Se2 contain a thin buffer layer of CdS in their standard configuration. In order to avoid cadmium in the device for environmental reasons, Cd-free alternatives are investigated. In this thesis, ZnO-based films, containing Mg or S, grown by atomic layer deposition (ALD), are shown to be viable alternatives to CdS. The CdS is an n-type semiconductor, which together with the n-type ZnO top-contact layers form the pn-junction with the p-type Cu(In,Ga)Se2. From device modeling it is known that a buffer layer conduction band (CB) position of 0-0.4 eV above that of the Cu(In,Ga)Se2 layer is consistent with high photovoltaic performance. For the Cu(In,Ga)Se2/ZnO interface this position is measured by photoelectron spectroscopy and optical methods to –0.2 eV, resulting in increased interface recombination. By including sulfur into ZnO, a favorable CB position to Cu(In,Ga)Se2 can be obtained for appropriate sulfur contents, and device efficiencies of up to 16.4% are demonstrated in this work. From theoretical calculations and photoelectron spectroscopy measurements, the shift in the valence and conduction bands of Zn(O,S) are shown to be non-linear with respect to the sulfur content, resulting in a large band gap bowing. ALD is a suitable technique for buffer layer deposition since conformal coverage can be obtained even for very thin films and at low deposition temperatures. However, deposition of Zn(O,S) is shown to deviate from an ideal ALD process with much larger sulfur content in the films than expected from the precursor pulsing ratios and with a clear increase of sulfur towards the Cu(In,Ga)Se2 layer. For (Zn,Mg)O, single-phase ZnO-type films are obtained for Mg/(Zn+Mg) < 0.2. In this region, the band gap increases almost linearly with the Mg content resulting in an improved CB alignment at the heterojunction interface with Cu(In,Ga)Se2 and high device efficiencies of up to 14.1%.
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Adler, Tobias [Verfasser], Andreas [Akademischer Betreuer] Klein та Heinz von [Akademischer Betreuer] Seggern. "Zn(O,S) Puffer Eigenschaften in Cu(In,Ga)Se2 Solarzellen / Tobias Adler. Betreuer: Andreas Klein ; Heinz von Seggern". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2013. http://d-nb.info/1108094082/34.
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Buffière, Marie. "Synthèse et caractérisation de couches minces de Zn (O,S) pour application au sein des cellules solaires à base de Cu (In, Ga) Se2." Nantes, 2011. http://www.theses.fr/2011NANT2057.
Анотація:
Un des défis concernant les cellules solaires à base de Cu(In,Ga)Se2 est le remplacement de la couche tampon de CdS déposée par bain chimique (CBD) par un matériau exempt de Cd déposé sous vide. L’objectif de ce travail est d’évaluer le potentiel des couches minces de Zn(O,S) déposées par co-pulvérisation cathodique RF (PVD) en tant que couche tampon alternative. Les propriétés matériau de ces couches ont été tout d’abord comparées à une référence (CBD)Zn(O,S) dont les conditions de dépôt ont été préalablement optimisées. Pour une composition équivalente, la technique de dépôt employée semble avoir un fort impact sur les propriétés optiques et structurales des couches. Le comportement électrique des dispositifs résultants s’en trouve également affecté. Dans le cas des cellules à couche tampon (CBD)Zn(O,S), nous avons mis en évidence la nécessité de prendre en compte l’ensemble du dispositif pour comprendre les phénomènes observés. Ces progrès ainsi qu’une meilleure compréhension des propriétés des couches (CBD)Zn(O,S) nous ont permis de réaliser des dispositifs stables sous éclairement avec des rendements de 16 % (sans couche anti-reflet). Pour les cellules à couche tampon (PVD)Zn(O,S), l’ajustement du taux de soufre a permis de contrôler l’alignement de bande à la jonction absorbeur/couche tampon et de permettre l’obtention de Jsc comparables à ceux des cellules avec (CBD)Zn(O,S). Bien que la structure telle quelle de la couche tampon (PVD)Zn(O,S) pour une teneur en soufre optimale ne permette pas d’obtenir les Voc attendus, ces résultats ouvrent de nouvelles perspectives de recherche sur la compréhension des hétéro-interfaces dans les cellules solaires Cu(In,Ga)Se2Thin film solar cell based on Cu(In,Ga)Se2 contain a thin, chemically deposited (CBD), cadmium sulfide (CdS) buffer layer. For environmental and industrial reasons, its replacement by a Cd-free material deposited under vacuum is among the challenges of the research community. In this work, co-sputtered (PVD)Zn(O,S) thin films have been studied as an alternative buffer layer. The properties of these layers have been compared to an optimized (CBD)Zn(O,S) reference. It is observed that the deposition technique has a strong impact on the optical and structural properties of the films for a given composition. As a result, the electrical behavior of the corresponding devices is also affected. The electrical characterization of (CBD)Zn(O,S)-buffered solar cells has shown that the absorber and the window layers properties strongly influence the performance of the cells. These progress together with the understanding of Zn(O,S) films properties makes it possible the realization of 16 % efficiency stable devices with a (CBD)Zn(O,S) buffer layer. Meanwhile, the tuning of the sulfur content has lead to the control of the conduction band offset in CIGSe/(PVD)Zn(O,S) devices and the achievement of similar Jsc than the one of (CBD)Zn(O,S)-buffered devices. Although the present structure of the (PVD)Zn(O,S) buffer layer is not suitable to obtain comparable Voc, these results offer many research perspectives in hetero-interface for a better understanding of Cu(In,Ga)Se2-based solar cells
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Santos, Damilson Ferreira dos. "S?ntese e caracteriza??o de tensoativos e estudo de equil?brio de fase dos sistemas CnH2n+2/H2O/CnH2n+1COONa/But-OH." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15934.
Анотація:
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Previous issue date: 2014-09-02Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
The growing utilization of surfactants in several different areas of industry has led to an increase on the studies involving solutions containing this type of molecules. Due to its amphiphilic nature, its molecule presents one polar part and one nonpolar end, which easily interacts with other molecules, being able to modify the media properties. When the concentration in which its monomers are saturated, the airliquid system interface is reached, causing a decrease in interfacial tension. The surfactants from pure fatty acids containing C8, C12 and C16 carbonic chains were synthesized in an alcoholic media using sodium hydroxide. They were characterized via thermal analysis (DTA and DTG) and via infrared spectroscopy, with the intention of observing their purity. Physical and chemical properties such as superficial tension, critical micelle concentration (c.m.c), surfactant excess on surface and Gibbs free energy of micellization were determined in order to understand the behaviour of these molecules with an aqueous media. Pseudo-ternary phase diagrams were obtained aiming to limit the Windsor equilibria conditions so it could be possible to understand how the surfactants carbonic chain size contributes to the microemulsion region. Solutions with known concentrations were prepared to study how the surfactants can influence the dynamic light scattering spectroscopy (DLS) and how the diffusion coefficient is influenced when the media concentration is altered. The results showed the variation on the chain size of the studied surfactant lipophilic part allows the conception of surfactants with similar interfacial properties, but dependent on the size of the lipophilic part of the surfactant. This variation causes the surfactant to have less tendency of microemulsionate oil in water. Another observed result is that the n-alcanes molecule size promoted a decrease on the microemulsion region on the obtained phase diagrams
O crescente uso de tensoativos nas mais diferentes ?reas da ind?stria tem levado a um aumento nos estudos envolvendo solu??es contendo este tipo de mol?cula. Devido a sua natureza anfif?lica, sua mol?cula apresenta uma parte polar e outra apolar, que facilmente interage com outros tipos de mol?culas, podendo modificar as propriedades do meio. Quando a concentra??o, na qual seus mon?meros saturam, a interface do sistema ar-l?quido, ? atingida promovendo a redu??o da tens?o interfacial. Os tensoativos dos ?cidos graxos puros com cadeias carb?nicas C8, C12 e C16 foram sintetizados em meio alco?lico, utilizando hidr?xido de s?dio. Eles foram caracterizados por an?lise t?rmica (DTA e DTG) e espectroscopia de infravermelho com o objetivo de se observar a pureza dos mesmos. Foram determinadas algumas propriedades f?sicoqu?micas como: tens?o superficial, c.m.c. , excesso de tensoativo na interface e energia livre de Gibbs de miceliza??o a fim de se entender o comportamento das intera??es dessas mol?culas com meio aquoso. Foram elaborados diagramas de fase pseudotern?rios com o intuito de realizar as delimita??es do equil?brio de Winsor para compreender como o tamanho da cadeia carb?nica dos tensoativos contribui com a regi?o de microemuls?o. Preparou-se solu??es com concentra??es conhecidas para se estudar como os tensoativos podem influenciar a espectroscopia de espalhamento din?mico de luz (Dynamic Ligth Scattering - DLS) e como o coeficiente de difus?o ? influenciado quando a concentra??o do meio ? alterada. Os resultados mostraram que o aumento ou diminui??o do tamanho da cadeia da parte lipof?lica dos tensoativos estudados permite conceber tensoativos com propriedades interfaciais similares, mas tamb?m dependente do tamanho da parte lipof?lica do tensoativo. Esta varia??o deixa o tensoativo com menor tend?ncia a microemulsionar ?leo em ?gua. Outro resultado observado ? que o tamanho das mol?culas de n-alcanos promoveu uma redu??o da regi?o de microemuls?o dos diagramas de fases obtidos
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Assis, Raimison Bezerra de. "S?ntese e caracteriza??o de ferrita ni-zn pelo m?todo dos precursores polim?ricos calcinada por energia de microondas." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12816.
Анотація:
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Previous issue date: 2013-07-04Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Magnetic ceramics have been widely investigated, especially with respect to intrinsic and extrinsic characteristics of these materials. Among the magnetic ceramic materials of technological interest, there are the ferrites. On the other hand, the thermal treatment of ceramic materials by microwave energy has offered various advantages such as: optimization of production processes, high heat control, low consumption of time and energy among others. In this work were synthesized powders of Ni-Zn ferrite with compositions Ni1- xZnxFe2O4 (0.25 ≤ x ≤ 0.75 mols) by the polymeric precursor route in two heat treatment conditions, conventional oven and microwave energy at 500, 650, 800 and 950?C and its structural, and morphological imaging. The materials were characterized by thermal analysis (TG/ DSC), X-ray diffraction (XRD), absorption spectroscopy in the infrared (FTIR), scanning electron microscopy (SEM), X-ray spectroscopy and energy dispersive (EDS) and vibrating sample magnetometry (VSM). The results of X-ray diffraction confirmed the formation of ferrite with spinel-type cubic structure. The extrinsic characteristics of the powders obtained by microwave calcination and influence significantly the magnetic behavior of ferrites, showing particles ferrimagn?ticas characterized as soft magnetic materials (soft), is of great technological interest. The results obtained led the potential application of microwave energy for calcining powders of Ni-Zn ferrite
Cer?micas magn?ticas t?m sido amplamente investigadas, principalmente com rela??o as caracter?sticas intr?nsecas e extr?nsecas destes materiais. Dentre os materiais cer?micos magn?ticos de interesse tecnol?gico, destacam-se as ferritas. Por outro lado, o tratamento t?rmico de materiais cer?micos por energia de microondas tem oferecido diversas vantagens, tais como: otimiza??o dos processos de obten??o, alto controle de aquecimento, menor consumo de tempo e energia entre outras. Neste trabalho, foram sintetizados p?s de ferritas Ni-Zn com composi??es Ni1-xZnxFe2O4 (0,25 ≤ x ≤ 0,75 mols) pela rota dos precursores polim?ricos em duas condi??es de tratamento t?rmico, em forno convencional e por energia de microondas a 500, 650, 800 e 950?C, e sua caracteriza??o estrutural, morfol?gica e magn?tica. Os materiais obtidos foram caracterizados por an?lises t?rmicas (TG/DSC), difra??o de raios x (DRX), espectroscopia de absor??o na regi?o do infravermelho (FTIR), microscopia eletr?nica de varredura (MEV), espectroscopia de raios X por dispers?o de energia (EDS) e magnetometria de amostra vibrante (VSM). Os resultados da difra??o de raios X confirmaram a forma??o da ferrita com estrutura c?bica do tipo espin?lio. As caracter?sticas extr?nsecas dos p?s obtidos e a calcina??o por microondas influenciaram de forma significativa o comportamento magn?tico das ferritas, apresentando part?culas ferrimagn?ticas, caracterizadas como materiais magn?ticos moles (macias), sendo de grande interesse tecnol?gico. Os resultados obtidos induziram o potencial de aplica??o de energia de microondas para a calcina??o de p?s de ferritas Ni-Zn
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Ramos, Rafaela. "Associa????o entre os polimorfismos BsmI e FokI do gene VDR, n??veis s??ricos de 25(OH)D e susceptibilidade ?? osteoporose em idosas." Universidade Cat??lica de Bras??lia, 2016. https://bdtd.ucb.br:8443/jspui/handle/tede/2171.
Анотація:
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Osteoporosis (OP) is a common osteometabolic disease among the elderly and may be associated with genetic components that influence bone metabolism. Due to regulatory action of vitamin D in osteomineral physiology, the expression of the vitamin D receptor gene (VDR) in bone tissue, it is able to influence the genetic determinants of bone mineral density (BMD) and the OP. Studies report the existence of polymorphisms related to the pathogenesis of OP, which can lead to changes in the mechanisms of the action of vitamin D. The BsmI and FokI polymorphisms were associated with changes in BMD suggesting thus a higher incidence and prevalence of fractures due to bone fragility. The objective of this study was to associate the presence of BsmI and FokI polymorphisms located in VDR gene, serum levels of 25(OH)D and susceptibility to OP for elderly women. It was observed that 58% of the study sample had levels of 25(OH)D below the threshold considered sufficient and 62% showed changes in BMD values consistent with the diagnosis of osteopenia or osteoporosis. For elderly women, vitamin D levels are not related to the reduction of BMD and presence of polymorphisms. In the evaluation of polymorphic sites it was found that, in this sample, 28% were positive for FokI polymorphism and 10% were positive for BsmI. The described results show that in elderly women, the BsmI polymorphisms FokI and are not related to vitamin D and osteoporosis.
A osteoporose (OP) ?? uma afec????o osteometab??lica comum em idosos, associada ou n??o a componentes gen??ticos que influenciam no metabolismo ??sseo. Devido ?? a????o reguladora da vitamina D na fisiologia osteomineral, a express??o do gene receptor da vitamina D (VDR) no tecido ??sseo ?? capaz de exercer influ??ncia na determina????o gen??tica da densidade mineral ??ssea (DMO) e OP. Estudos reportam a exist??ncia de polimorfismos relacionados com a etiopatogenia da OP os quais podem determinar altera????es nos mecanismos de a????o da vitamina D. Os polimorfismos BsmI e FokI foram associados com varia????es na DMO sugerindo uma maior incid??ncia e preval??ncia de fraturas por fragilidade ??ssea. Desta forma, o objetivo deste estudo foi associar a presen??a dos polimorfismos BsmI e FokI localizados no gene VDR, as concentra????es s??ricas de 25-hidroxivitamina D (25(OH)D) e a susceptibilidade ?? osteoporose em idosas. Para tanto, foram inclu??das 50 idosas com m??dia de idade de 71,74 ?? 7,80 anos (60 ??? 94 anos). Os polimorfismos BsmI e FokI foram pesquisados e os dados sobre os n??veis de 25(OH)D e DMO foram coletados mediante acompanhamento ambulatorial. Observou-se que 58% da amostra estudada possui n??veis de 25(OH)D abaixo do limiar considerado suficiente e 62% apresentaram altera????es nos valores de DMO compat??veis com o diagn??stico de osteopenia ou osteoporose. Nas idosas avaliadas os n??veis de vitamina D n??o est??o relacionados com a redu????o da DMO e presen??a dos polimorfismos. Na avalia????o dos s??tios polim??rficos verificou-se que, nessa amostra, 28% apresentaram resultado positivo para o polimorfismo FokI e 10% apresentaram positividade para BsmI. Os resultados descritos evidenciam que, nas idosas avaliadas, os polimorfismos BsmI e FokI n??o se encontram relacionados com os n??veis de vitamina D e osteoporose.
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Buffiere, Marie. "Synthèse et caractérisation de couches minces de Zn(O,S) pour application au sein des cellules solaires a base de Cu(In,Ga)Se2." Phd thesis, Université de Nantes, 2011. http://tel.archives-ouvertes.fr/tel-00871274.
Анотація:
Un des défis concernant les cellules solaires à base de Cu(In,Ga)Se2 est le remplacement de la couche tampon de CdS déposée par bain chimique (CBD) par un matériau exempt de Cd déposé sous vide. L'objectif de ce travail est d'évaluer le potentiel des couches minces de Zn(O,S) déposées par co-pulvérisation cathodique RF (PVD) en tant que couche tampon alternative. Les propriétés matériau de ces couches ont été tout d'abord comparées à une référence (CBD)Zn(O,S) dont les conditions de dépôt ont été préalablement optimisées. Pour une composition équivalente, la technique de dépôt employée semble avoir un fort impact sur les propriétés optiques et structurales des couches. Le comportement électrique des dispositifs résultants s'en trouve également affecté. Dans le cas des cellules à couche tampon (CBD)Zn(O,S), nous avons mis en évidence la nécessité de prendre en compte l'ensemble du dispositif pour comprendre les phénomènes observés. Ces progrès ainsi qu'une meilleure compréhension des propriétés des couches (CBD)Zn(O,S) nous ont permis de réaliser des dispositifs stables sous éclairement avec des rendements de 16 % (sans couche anti-reflet). Pour les cellules à couche tampon (PVD)Zn(O,S), l'ajustement du taux de soufre a permis de contrôler l'alignement de bande à la jonction absorbeur/couche tampon et de permettre l'obtention de Jsc comparables à ceux des cellules avec (CBD)Zn(O,S). Bien que la structure telle quelle de la couche tampon (PVD)Zn(O,S) pour une teneur en soufre optimale ne permette pas d'obtenir les Voc attendus, ces résultats ouvrent de nouvelles perspectives de recherche sur la compréhension des hétéro-interfaces dans les cellules solaires Cu(In,Ga)Se2
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Sáez, Araoz Rodrigo [Verfasser]. "Chemical bath deposition of Zn(S,O) buffer layers and application in Cd-free chalcopyrite-based thin-film solar cells and modules / Rodrigo Sáez Araoz." Berlin : Freie Universität Berlin, 2009. http://d-nb.info/1023816695/34.
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Fabert, Sabine. "Élaboration et caractérisation de couches minces de Zn(O,S), Mo et ZnO : Al déposées par pulvérisation magnétron pour la réalisation de cellules photovoltaïques CIGS." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4021/document.
Анотація:
Cette thèse s’inscrit dans le cadre d’un partenariat entre l’Institut des Matériaux Jean Rouxel et la société Crosslux qui souhaite développer un vitrage photovoltaïque semi-transparent par pulvérisation magnétron. Dans ce contexte, ce travail concerne la mise au point du dépôt par pulvérisation cathodique des couches de contact et de la couche tampon entourant le matériau actif CIGS. La réalisation et la caractérisation d’une couche tampon en Zn(O,S) constituent le coeur de cette thèse afin de proposer une alternative à la couche CdS, matériau toxique déposé par bain chimique, technique peu adaptée à la réalisation de grandes surfaces. L’optimisation de la couche tampon Zn(O,S) a mis en évidence un ajustement possible de la composition chimique entre ZnO0,2S0,8 et ZnO2S0,5 et un contrôle des propriétés cristallines et optiques. Des films denses de ZnO0,42S0,66 présentent des caractéristiques satisfaisantes pour l’application visée avec une transparence de 90 % et un gap optique de 2,5 eV. Le contact arrière en molybdène (Mo) est constitué d’une structure bicouche optimisée : une première couche peu dense assure une bonne adhérence au substrat de verre et une couche supérieure dense permet d’atteindre une faible résistivité électrique de 22.10-6 Ω.cm. Le contact avant en oxyde de zinc dopé aluminium (AZO), réalisé en mode DC pulsé et réactif Ar/O2, présente après recuit à 250 °C sous azote, une transmittance moyenne dans le visible de 93 %, une résistivité de 3.10-3 Ω.cm et une figure de mérite de 6,45.10-3 Ω-1. Ce travail constitue une contribution significative à la réalisation complète de cellules CIGS par pulvérisation magnétronThis PhD work has been performed within collaboration between the Institute of Materials Jean Rouxel and Crosslux Company, aiming at developing semi-transparent photovoltaic glasses using only magnetron sputtering. This work is focused on magnetron sputtering deposition of both contact layers (Mo and AZO) and buffer layer dedicated to CIGS solar cell. The main focus of this work was the optimization of the Zn (O, S) buffer layer in order to replace the CdS layer deposited by chemical bath unsuitable for large areas. The Zn(O, S) buffer layer study highlights a possible adjustment of the chemical composition between ZnO0.2S0.8 and ZnO2S0.5 and control of the crystalline and optical properties. ZnO0.42S0.66 dense layers exhibit satisfying properties for the targeted application with a visible transparency equal to 90 % and an optical gap of 2.5 eV. The molybdenum back contact (Mo) is an optimized bi-layered structure allowing a good adhesion to the glass substrate and low electrical resistivity (in the 20.10-6 Ω.cm range) thanks to the upper dense layer. The aluminum-doped zinc oxide (AZO) front contact deposited by Ar/O2 reactive pulsed DC mode and annealed at 250° C under nitrogen, exhibits an average transmittance of 93 % in the visible range, a resistivity of 3 10-3 Ω.cm and a figure of merit of 6.45 10-3 Ω-1. This work stands as a significant contribution to the deposition of the entire CIGS solar cell by magnetron sputtering
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Bugot, Cathy. "Elaboration d'oxydes et de sulfures à grande bande interdite pour les cellules photovoltaïques à base de Cu(In,Ga)Se2 par dépôt chimique en phase vapeur par flux alternés (ALD) activé par plasma." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066499/document.
Анотація:
La thèse présentée ici a pour objectif de développer des matériaux innovants et performants pour la fabrication de la couche tampon des cellules photovoltaïques en couches minces à base de Cu(In,Ga)Se2 (CIGS). Pour la première fois, des couches minces d'In2(S,O)3 et de Zn(O,S) ont été réalisées par dépôt chimique en phase vapeur par flux alternés assisté par plasma afin de remplacer la couche tampon traditionnelle en sulfure de cadmium. En apportant des espèces plus réactives, cette méthode permet d'effectuer des réactions qui ne pourraient pas avoir lieu par procédé thermique. La comparaison des deux procédés a permis l'évaluation de leurs atouts et de leurs contraintes. Par exemple, l'In2(S,O)3 n'a pu être synthétisé que par cette méthode, via des mécanismes surfaciques d'échange entre des radicaux d'oxygène et le soufre de l'In2S3. Pour augmenter les performances des cellules CIGS/In2(S,O)3 jusqu'à 11,9%, le procédé de synthèse initial a été amélioré en corrélant les études de Spectroscopie Photoélectronique X et celles de spectrométrie de masse. En parallèle, il a été montré que la température de croissance avait un effet notable sur les propriétés opto-électroniques des cellules CIGS/Zn(O,S) et qu'il existait des optimums de performance à basse (Tdep < 160°C) et haute (Tdep > 200°C) températures. L'optimum situé à basse température s'explique par les propriétés favorables des couches minces de Zn(O,S) synthétisées par procédé thermique, tandis que celui situé à haute température est dû à l'existence de mécanismes d'interdiffusion à l'interface Zn(O,S)/CIGS. Un rendement de 15,6% a pu ainsi être obtenuThis thesis focuses on the development of innovative and efficient materials for the fabrication of the buffer layer of Cu(In,Ga)Se2 (CIGS) thin film solar cells. For the first time, In2(S,O)3 and Zn(O,S) thin films were synthesized by Plasma Enhanced Atomic Layer Deposition (PEALD) in order to substitute the conventional cadmium sulfide buffer layer. By creating reactive species, this deposition technique allows reactions which could not be possible using thermal ALD. The comparison of both methods allows the evaluation of their respective assets and constraints. For instance, In2(S,O)3 thin films could only be achieved using PEALD through exchange reaction mechanisms between oxygen radicals from the plasma and sulfur atoms of In2S3 growing film. In order to obtain CIGS/In2(S,O)3 solar cells with efficiencies of 11.9%, the initial deposition process was improved by correlating X-Ray Photoelectron Spectroscopy and Quadrupole Mass Spectrometry analyses. At the same time, the deposition temperature proved to have a crucial effect on CIGS/Zn(O,S)-ALD device opto-electronic properties and we evidenced the existence of two deposition temperature ranges, at Tdep < 160°C and Tdep > 200°C, where the performances are enhanced. In the low temperature range, the high performances were explained by specific Zn(O,S) properties, while at high temperature they are enhanced by favorable interdiffusion mechanisms at the CIGS/Zn(O,S) interface. Increasing the deposition temperature allowed the fabrication of CIGS/Zn(O,S) solar cells with efficiencies up to 15.6%
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Hildebrandt, Thibaud. "Optimisation des interfaces absorbeur/couche tampon/fenêtre avant dans les cellules solaires à base de Cu(In,Ga)Se2." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066720.
Анотація:
Le remplacement du CdS dans les cellules solaires à base de Cu(In,Ga)Se2 est un des défis majeurs de la communauté. À ce jour un des matériaux les plus prometteurs est le Zn(S,O,OH) déposée par voie chimique en solution. En raison de la faible vitesse de dépôt du matériau et des phénomènes de métastabilités présents dans les dispositifs formés, il apparaît nécessaire d’optimiser les conditions expérimentales et les interfaces. La 1ère partie de ces travaux a été consacré à l’optimisation des conditions de dépôt des couches minces de Zn(S,O,OH) grâce à l’introduction d’additifs. Il a été possible de souligner l’effet des additifs sur la composition des couches déposées et sur les vitesses de réaction. La 2ème partie de ces travaux a été consacrée à l’optimisation des conditions de dépôt par pulvérisation cathodique de la fenêtre avant (Zn,Mg)O/ZnO :Al permettant une diminution des phénomènes de métastabilité et une limitation de la migration de sodium jusqu’au Zn(S,O,OH). Ces conditions combinées à une variation de la composition de la surface du CIGSe a permis d’obtenir des rendements de photo-conversion supérieurs à ceux des références à base de CdSThe replacement of CdS-based buffer layer in Cu(In,Ga)Se2 solar cells has been one of the main challenges of the research community for the last decade. Today, one of the most promising alternative material is the chemically bath deposited Zn(S,O,OH). Because of its low deposition rate and of metastable behavior, it becomes necessary to proceed to an optimization of experimental conditions and of the various interfaces. The first part of this work has been dedicated to the optimization of the deposition bath thanks to the introduction of new additives. It has been possible to underline the additive effects on both the deposition rate and on the chemical composition of the deposited layers. The second part of this work has been dedicated to the optimization of the (Zn,Mg)O/ZnO:Al window layer. Thanks to an improvement of the sputtering conditions, it has been possible to reduce metastability of the solar cells, and to limit sodium migration up to the Zn(S,O,OH) layer. These optimized conditions combined to the variation of the CIGSe surface composition have allowed us to outperform CdS-based references solar cells
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Drawin, Stefan. "Etude en faisceaux moléculaires croisés de la collision réactive d'état à état : O (singulet D) + H2 (X singulet sigma, V) donne OH (X doublet PI et A doublet sigma, V, J) plus H (singulet S)." Paris 13, 1990. http://www.theses.fr/1990PA132004.
Анотація:
Deux voies réactives, se distinguant par l'état d'excitation électronique du produit OH, sont étudiées en milieu très raréfié pour contribuer a la compréhension des mécanismes réactionnels microscopiques en jeu. Pour la première voie exothermique donnant oh (état fondamental), les niveaux rovibrationnels sont sondes par fluorescence-induite-par-laser; d'autre part, l'établissement d'une carte de flux est assure grâce a l'analyse en angle de la vitesse de oh par mesure du temps-de-vol. Pour la seconde voie, l'endothermicité est surmontée par une excitation vibrationnelle de l'hydrogène sur des niveaux supérieurs à 5, par impact avec des électrons lents. Les niveaux rovibrationnels de OH (premier état excite) sont sondes par analyse en longueur d'onde de la fluorescence spontanée. Dans les deux cas, l'oxygène atomique est obtenu par dissociation de l'oxygène moléculaire (ensemence dans l'hélium comme gaz porteur) dans une décharge radiofréquence
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Charef, Abdelkrim. "La Nature et le rôle des phases fluides associées à la minéralisation Pb-Zn dans les formations carbonatées et leurs conséquences métallogéniques études des inclusions fluides et des isotopes (H,C,O,S,Pb) des gisements des Malines (France), Jbel Hallouf-Sidi Bou Aouane et Fedj-el-Adoum (Tunisie)." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37596635t.
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Souza, Ana Carolina Bello de. "Estudo te?rico das rea??es de SN2 em fase gasosa: RCI+OH??ROH+CI? (R = Metil, Etil, n-Propil, i-Propil, n- Butil, s-Butil e t-Butil)." Universidade Federal Rural do Rio de Janeiro, 2012. https://tede.ufrrj.br/jspui/handle/jspui/1547.
Анотація:
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
In this work, the theoretical study of the gas-phase bimolecular nucleophilic substitution reaction, CH3Cl + OH- CH3OH + Cl-, is introduced, aiming the description of the potential energy surface, the calculation of rate constants and the investigation of the effect of increasing the side chain (changing the CH3 radical in the reaction cited above by the radicals ethyl, n-propyl, i-propyl, n-butyl, s-butyl e t-butyl). The theoretical calculations have been first performed at the MP2/6-31+G(d) level for the geometry optimizations and vibrational frequencies calculations. Single point calculations at the CCSD(T)/6-31+G(d) level have also been performed in order to improve the total energies for the stationary points. However, the relative energies of these stationary points at both MP2 and CCSD(T) level shown close results, so that the single point calculations at the CCSD(T) level have not been proved strictly necessary and have therefore not been performed for all the points along the potential energy surface. The minimum energy path has been described by the intrinsic reaction coordinate method, calculated at the MP2/6-31+G(d) by performing sequential geometry optimizations starting from the saddle point. The calculated enthalpy difference at 298K for the reaction has been determined as -49.5 kcal/mol, in good agreement with the literature value: -50.5 kcal/mol. The calculated rate constant has been obtained as 1.41 x 10-9 cm3.molecule-1.s-1, at 298,15K, in excellent agreement with the experimental data: 1.3 ? 1.6 x 10-9 cm3.molecule-1.s-1.Moreover, the rate constants show non-Arrhenius behavior, decreasing as the temperature increases, which is consistent with the experimental expectation. In this way, the performance of the variational transition state theory for this reaction can be considered satisfactory. By increasing the side chain of the reactant, other reaction channels have been observed: the bimolecular elimination E2 channel and the attack of the nucleophile from the same plane of the exit group (the front-SN2).For these reactions of the alkyl chlorides on n carbon atoms (1 < n ? 4), the B3LYP/6-31+G(d,p) level has been adopted for geometry optimizations and vibrational frequencies. Then, single point calculations at the CCSD(T)/6-31+G(d,p)//B3LYP/6- 31+G(d,p) level have been performed. A comparison of the reaction channels, back- SN2 and E2, shows that the E2 channel is kinetically favored, whereas the SN2 products are thermodynamically more stable. As expected, high values for the potential height have been observed for the front-SN2, being these channels disfavored in all cases. In general, the energy of the saddle points in respect to the isolated reactants slightly depend upon the size of the side chain.
Este trabalho trata do estudo te?rico das rea??es de substitui??o nucleof?lica de segunda ordem, CH3Cl + OH- CH3OH + Cl-, em fase gasosa, visando estudar a superf?cie de energia potencial, obter as constantes de velocidade e ainda verificando o efeito do aumento da cadeia lateral (trocando o radical CH3 na rea??o descrita acima por radicais etil, n-propil, i-propil, n-butil, s-butil e t-butil). Primeiramente, c?lculos te?ricos para otimiza??es de geometria e frequ?ncia foram realizados em n?vel MP2/6-31+G(d) para a rea??o CH3Cl + OH- CH3OH + Cl- e, em seguida, c?lculos single-point em n?vel CCSD(T)/6-31+G(d) foram realizados para corrigir os valores da energia eletr?nica dos pontos estacion?rios obtidos no caminho de rea??o. Entretanto, os valores obtidos para as energias relativas em n?veis MP2 e CCSD(T) foram muito pr?ximos, n?o sendo estritamente necess?rio refinar,atrav?s de c?lculos single-point em n?vel CCSD(T)/6- 31+G(d),os valores de energia de todos os pontos obtidos na superf?cie de energia potencial. O caminho de rea??o menor energia foi descrito pela coordenada de rea??o intr?nseca, calculada por otimiza??es de geometrias de uma sequ?ncia de configura??es ao redor do ponto de sela em n?vel MP2/6-31+G(d). A diferen?a de entalpia a 298K calculada para a rea??o foi de -49,5 kcal/mol, em bom acordo com o dado da literatura, -50,5 kcal/mol. A constante de velocidade da rea??o obtida foi de 1,41 x 10-9 cm3.mol?cula-1.s-1, a 298,15K, em excelente acordo com o dado experimental: 1,3 ? 1,6 x 10-9 cm3.mol?cula-1.s-1. Al?m disso, as constantes de velocidade globais apresentam comportamento n?o-Arrhenius, diminuindo conforme a temperatura aumenta, em um perfil consistente com a observa??o experimental. Dessa forma, a aplica??o da teoria de estado de transi??o se mostra satisfat?ria para essa rea??o. A partir do aumento da cadeia lateral, outros canais de rea??o foram observados, em prov?vel competi??o ? substitui??o nucleof?lica de ordem 2: a elimina??o de segunda ordem, E2. O ataque do nucle?filo pela frente da cadeia tamb?m foi obtido e investigado. Para as rea??es dos cloretos de alquila com cadeia lateral de n carbonos (1 < n ? 4), o n?vel B3LYP/6- 31+G(d,p) foi adotado para c?lculos de otimiza??es e frequ?ncias. Posteriormente, c?lculos em n?vel CCSD(T)/6-31+G(d,p)//B3LYP/6-31+G(d,p) foram realizados. Comparando os canais de rea??o de substitui??o nucleof?lica back e de elimina??o, o canal cineticamente favorecido foi o de elimina??o, por?m os produtos termodinamicamente mais est?veis s?o os de substitui??o nucleof?lica. Como esperado, observa-se uma barreira de potencial muito alta para as rea??es substitui??o pela frente, sendo esses canais desfavorecidos em todos os casos.Em geral, a diferen?a de energia dos pontos de sela em rela??o aos reagentes isolados mostra pequena depend?ncia com o aumento da cadeia lateral linear
20
Shih, Pei-Hsuan, and 石沛軒. "Chemical bath deposited Zn(S,O,OH) thin-film as an alternative buffer layer for Cu2ZnSnS4 solar cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/2m34nj.
Анотація:
碩士國立臺灣海洋大學
光電科學研究所
102
The quantum efficiency of a CdS-buffered Cu2ZnSnS4 (CZTS) solar cell drops at short wavelengths due to the optical absorption of the CdS layer. Further improvement in short circuit current (Jsc) at shorter wavelengths can be achieved by replacing CdS with other appropriate wider band gap buffer materials. Being a wide bandgap material, non-toxic in nature, low-cost and high material abundance, CBD grown ZnS is one of the promising candidates for alternative buffer layers. Normally, in device fabrication the CBD method has many advantages, such as low deposition temperature, low-cost fabrication process, and easy to scale up for industrial fabrication. Besides, of most importance is the CBD method’s usage of ammonia solution enabling restoration of the positive surface charge of CZTS for the effective p-n junction formation. In this thesis, Zn(S,O,OH) thin film were synthetized by using zinc sulfate hepta-hydrate (ZnSO4•7H2O), thiourea (SC(NH2)2) and ammonium hydroxide (NH4OH) solution in DI water at relatively low temperature. We have optimized the concentrations of respective reactants concentrations, pH value and reaction temperature to obtain Zn(S,O,OH) thin film as a good buffer layer for CZTS. The band gap, and the band positions of this material are tunable by varying S/O ratios, resulting from various concentrations of thiourea and pH values. The elemental compositions, optical properties and coexisting multiple phases in the films have been investigated sequentially. Finally, we have used successfully prepared the Zn(S,O,OH) film in the final solar cell with a better performance to replace the conventional CdS buffer layer. The champion cell has achieved 4.1% in efficiency, which is comparable to the 5.69% efficiency of the standard CdS-based. The external quantum efficiency (EQE) spectra of our solar cell also evidenced the enhancement of carrier collections at short wavelengths.
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Adler, Tobias. "Zn(O,S) Puffer Eigenschaften in Cu(In,Ga)Se2 Solarzellen". Phd thesis, 2013. https://tuprints.ulb.tu-darmstadt.de/3725/7/Tobias%20Adler%20Dissertation.pdf.
Анотація:
In dieser Arbeit wurden die chemischen und elektronischen Eigenschaften der Absorber/Puffer Grenzfläche einer Cu(In,Ga)Se2 Solarzelle mit Standard CdS Puffer und alternativem ZnO1−xSx (ZnOS) Puffer an industrienahen Proben charakterisiert. Hierfür wurde zum einen die Röntgen-Photoelektronenspektroskopie und zum anderen Impedanzmessungen verwendet.
Die erhaltenen Ergebnisse der XPS Messungen zeigen die elektronische Struktur des Valenz bandmaximums der einzelnen Materialien. Über die Anpassung der Valenzbänder und der Bandlücken der einzelnen Materialien wird die Anpassung der Leitungsbänder bestimmt. Der Auger Parameter gibt für die ZnOS Puffer die chemische Zusammensetzung wieder. In Verbindung mit Materialkenndaten aus der Literatur konnten aus den erhaltenen Werten mögliche Banddiagramme zur Interpretation des Bauteilverhaltens entwickelt werden.
Aus den durchgeführten Impedanzmessungen resultiert das kapazitive Verhalten der Solarzellen. Das kapazitive Verhalten zeichnet sich durch Transienten der Impedanzparameter aus. Eine mögliche Interpretation der Transienten ist die Diffusion von Kupfer-Defekten in der Absorberschicht. Hiermit können die in der Literatur bekannten Phänomene beim Anlegen einer negativen Spannung erklärt werden. Andere aus der Literatur bekannte metastabile Phänomene sind mit dieser Theorie nicht erklärbar, sind aber auch nicht notwendigerweise auf die gleiche Ursache zurück zu führen und damit losgelöst voneinander zu betrachten.
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Cheng, Hsueh-Erh, and 鄭雪兒. "Effects of In(S,O,OH) buffers on device performance of CIGS solar cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/39748064968383291101.
Анотація:
碩士國立東華大學
電機工程學系
99
The In(S,O,OH) buffer layers were deposited by the chemical bath deposition process for the CIGS solar cells. We used indium chloride (InCl3), thioacetamide (CH3CSNH3), acidic acid (CH3COOH), and hydrochloric acid (HCl) to deposit the In(S,O,OH) thin films. The concentrations of indium chloride or thioacetamide were varied to investigate their effects on the properties of the as-deposited In(S,O,OH) films. The CBD In(S,O,OH) buffer layers were applied on the CIGS solar cells with a device structure of glass/Mo/CIGS/buffer/i-ZnO/ZnO:Al. The current-voltage characteristics of the CIGS solar cells with the In(S,O,OH) or CdS buffers were studied. The surface morphologies, binding energies, and crystal structure of In(S,O,OH) films were characterized by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), respectively. The optical properties of In(S,O,OH) films were measured by suing the ultraviolet-visible spectrometer.
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Tseng, Tsung-yi, and 曾宗義. "An interdiffusion study of a Zn(S,O)/CZTSe bilayer structure for photovoltaic applications." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/76477871809183576602.
Анотація:
碩士國立中山大學
材料與光電科學學系研究所
103
This experiment tried to use multiple methods to make ZnS thin film and dope O to form ZnS1-xOx (Zn(S,O)) thin film, and finally selected Reactive Sputtering as the most fittable method. Form ZnS thin film formed by Reactive Sputtering with XRD and assure if the film was single phase or not. Next dope the oxygen with proportion PO2/Ptotal =1% to form ZnS1-xOx thin film and estimated the value of x was 0.2 approximately. After Zn(S,O) thin film formed, replaced CdS to form on Cu2ZnSnSe4 (CZTSe). The result revealed the adhesion was not good observed from SEM figure and the interdiffusion was not obvious observed from GIXRD figure. To improve the scale of interdiffusion and adhesion, anneal the factor for two minutes on 400oC and 500oC separately. The result revealed the adhesion was better than before annealing on SEM gragh, the peak value of Zn(S,O) disappeared on 500oC, but the peak value of Zn(S,O) existed on 400oC. However, the scale of interdiffusion did not broaden apparently from GIXRD figure.
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YU-ROU, KO, and 柯玉柔. "Utilization of La- and Sn- codoped Zn(O,S) for photocatalytic hydrogenation reaction of azobenzene." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/t4vg4m.
Анотація:
碩士國立臺灣科技大學
材料科學與工程系
107
In this research, the La- and Sn- codoped ZnOS photocatalyst powders at different La and Sn contents powder were prepared in our laboratory for photocatalytic hydrogenation reduction of azobenzene to aniline. There were five kinds of powders prepared: 10La-Zn(O,S), 10La2.5Sn-Zn(O,S), 10La5Sn-Zn(O,S), 10La10Sn-Zn(O,S), and 10Sn-Zn(O,S). Here, the hydrogenation reduction efficiency, powder structure and properties including electrical properties and optical properties of lanthanum- and tin- codoped Zn(O,S) powders were evaluated. In this experiment, we analyzed the powders with XRD, SEM, TEM, XPS, EPMA, electrochemical EIS impedance spectrum, and DRS. UV-Vis, GC-MS, and HER were used to analyze the retained liquid after the hydrogenation reduction of La- and Sn-codoped ZnOS for identifying the product.
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Chen, Yun-Fu, and 陳畇甫. "Non-toxic high-efficiency CZTSSe solar cells using Zn(O,S) instead of CdS buffer layer." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/93f9k2.
Анотація:
碩士國立臺灣海洋大學
光電科學研究所
107
In this thesis, we first attempted to deposit a non-toxic zinc sulfide (Zn(O,S)) instead of a toxic cadmium sulfide (CdS) buffer layer by chemical bath method (CBD) to form a p-n junction with the absorption layer CZTSSe, but found that the CBD method can lead to problem of forming zinc hydroxide (Zn(OH)2), which is undesired; further, we solved the problem by depositing Zn(O,S) using atomic layer epitaxy (ALD), which also greatly improved the conversion efficiency of the formed CZTSSe solar cell, with the best cells reaching 9.77% in efficiency. During the study, we first deposited (Zn(O,S)) using the common CBD method. In order to control the conduction band offset between the buffer layer and the absorption layer (CZTSSe), we tried to adjust the oxygen to sulfur ratio of the buffer layer by changing the concentration of S in the CBD precursor. However, it has been found that the oxygen-sulfur ratio in the zinc oxysulfide (Zn(O,S)) deposited by the CBD method is not easily changed by adjusting the concentration of the sulfur in the CBD precursor. According to X-ray photoelectron spectroscopy (XPS) analysis, when the sulfur precursor content is increased, the peak signal center of oxygen shifts from 531.0 eV to 531.8 eV. We think that this is because the hydroxide of ammonia in the solution will combine with zinc to form zinc hydroxide (Zn(OH)2). We also found through scanning electron microscopy (SEM) top view that there are many white particles on the surface of the sample, which is inferred also to be zinc hydroxide (Zn(OH)2). Zinc hydroxide (Zn(OH)2) has a poor optical penetration rate, which causes a decrease in the fill factor (FF), so zinc hydroxide (Zn(OH)2) is detrimental to the p-n junction. In addition, we also found from the top view that after soft baking at 200 °C, some cracks occur between the Zn(O, S) grain boundaries, which may lead to leakage problem in the solar cells. Considering that the CBD method is not easy to control the S/O proportion and thickness, we try to grow Zn(O, S) using atomic layer deposition (ALD). The results show that the performance of CZTSSe solar cells using ALD-growth zinc oxysulfide (Zn(O,S)) is excellent, and there is no crossover between light and dark J-V curves, indicating that there are fewer defects at the p-n junction. By adjusting the appropriate ratio of oxygen to sulfur, using a zinc oxysulfide (Zn(O,S)) buffer layer with a thickness of about 50 nm, we finally fabricated the toxic-free ALD CZTSSe solar cells, with the best cells showing the open circuit voltage (Voc) reaching 460 mV and the fill factor reaching 58.1%; the short-circuit current density (Jsc) was increased from the original 28.7 (CBD method) to 36.07 mA/cm2; the series resistance (Rs) was also reduced from 4.38 to 3.34 (Ω.cm2), and eventually the efficiency reached 9.77% in efficiency.
26
Glatzel, Thilo [Verfasser]. "Kelvinsondenkraftmikroskopie am Heteroübergang (Zn,Mg)O/Cu(In,Ga)(S,Se)2 - Chalkopyrit / von Thilo Glatzel." 2004. http://d-nb.info/970369573/34.
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Kuo, Bing-Hau, and 郭柄豪. "Microstructure and Optical Properties of Zn(O,S) Thin Films Prepared by Radio Frequency Magnetron Sputtering." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/13188209551021189521.
Анотація:
碩士國立中興大學
材料科學與工程學系所
101
Cu(In,Ga)Se (CIGS) solar cell is one of most promising material in thin film solar cell. The chemical bath deposition CdS is typically used as buffer layer in high efficiency solar cell. However, Cd is very toxic and taken consideration in great impact to environment. It is quite important issue for mass production to search Cd-free alternated buffer layer and develop all-vacuum process in the future. A series of ZnO1−xSx films prepared by radio-frequency reactive magnetron sputtering on soda-lime glasses as substrates. The composition, structure, and optical properties of the films deposited at different RF power, O2/(Ar+O2) ratio and substrate temperature were studied. The structure of the films deposited under various process parameters was characterized by XRD revealed that the films are wurtzite structure. The XRD peak shift to lower angle position with increasing RF power. The layer composition show that oxygen concentration decrease from 12.63 to 7.61 at.% and sulfur increase from 35.98 to 40.71 at.% as RF power increases. The optical absorption edge shift from 4.12 to 3.88 eV (red shift effect). Amorphous structure was found as O2/(Ar+O2) excess 4%. ESCA show the content of oxygen increase from 10.79 to 62.31 at.% and sulfur decrease from 40.35 to 4.55 at.% with oxygen flow increase. The optical transmission spectra show absorption edge shift 4.03 to 4.17 eV (blue shift effect). The XRD peak shift to higher angle was observed as substrate temperature increased. From TEM observation, the films were wurtzite structure with (002) preferred orientation. The optical absorption edge shift from 4.10 to 4.03 eV (red shift effect).
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Teng, Yen-Ching, and 鄧彥箐. "Enhanced Performance of CZTSSe Solar Cells via Interface Engineering of Zn(O,S)/CdS Double Buffer Layers." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/g9f636.
29
Chen, Chih Zui, and 陳致睿. "Depth Profiling Electronic Properties of CIGSSe-based Thin Film Solar Cell with Zn(O,S) Buffer Layer." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/44712385357225192516.
30
Hsieh, Tsung Min, and 謝琮民. "Annealing effect of znic oxysulfide (Zn(S,O)) buffer layer on CIGS (copper indium gallium diselenide) solar cell efficiency." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/11548541338768977386.
Анотація:
碩士長庚大學
化工與材料工程學系
101
This study focus on the chemical bath deposition (CBD) to prepare the buffer layer on CIGS solar cell. Using zinc sulfate, thiourea, hydrazine, and ammonium hydroxide to deposited the Zn (S,O) on substrate instead of CdS buffer layer. Some analytic method including FESEM, XRD, UV-VIS and Hall Effect measurement were used to analyze the CBD-derived nanosized Zn (S,O) buffer layers on CIGS thin film solar cells. The optical and electric properties of the Zn(S,O) layers can be improved after rapid thermal annealing (RTA) treatment. The Zn(S,O) properties are compared for samples annealed under various atmospheres. The resulting film thickness of the annealed Zn(S,O) is 80-100 nm. The band gap decreases from 3.8 eV to 3.3 eV and the light transmittance is improved to more than 95% after the annealing treatment in oxygen. The oxygen-annealed sample had the S/(S+O) ratio of 0.28 and S/Zn ratio of 0.72. The CIGS solar cell consisting of the annealed Zn(S,O) buffer layer exhibites a higher efficiency (6.15%) than that with the un-annealed Zn(S,O) (4.56%). The solar cell performance is correlated with the deposited Zn(S,O) characteristics. The significantly higher carrier concentration, more light transmittance, and the better crystalline structure of the oxygen-annealed Zn(S,O) film contribute to the improved cell performance.
31
Tsao, Hsiang-Wei, and 曹翔崴. "Investigation of Light Soaking Effect on Chemical Bath Deposited Zn(O,S) Buffer Layer-based Cu(In,Ga)(S,Se)2 Thin Film Solar Cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/35z5jr.
32
Hsieh, Hua-Yu, and 謝化宇. "Synthesis, Characterization and Molecular Structure Studies by NMR Spectroscopy and X-Ray Single-Crystal Determination On Metalloporphyrins : M(Por)(L)n, M = Ni、Cu and Zn , Por = N-NHCO-(o-OH)C6H4-tpp." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/57179945564294884728.
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Fíla, Jan. "Hledání fosfoproteinů účastnících se aktivace pylu tabáku in vitro." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-305610.
Анотація:
5 Abstract Tobacco mature pollen rehydrates in vivo on a stigma tissue, and develops into the rapidly-growing pollen tube. This rehydration process is accompanied by the de-repression of stored mRNA transcripts, resulting in the synthesis of novel proteins. Furthermore, such metabolic switch is also likely to be regulated on the level of post-translational modifications of the already-present proteins, namely via phosphorylation, since it was shown to play a significant regulatory role in numerous cellular processes. Since only a minor part of proteins is phosphorylated in a cell at a time, the employment of various enrichment techniques is usually of key importance. In this diploma project, metal oxide/hydroxide affinity chromatography (MOAC) with aluminium hydroxide matrix was applied in order to enrich phosphoproteins from the mature pollen and the 30-minute in vitro activated pollen crude protein extracts. The enriched fraction was separated by both 2D-GE and gel-free liquid chromatography (LC) approaches with subsequent mass spectrometric analyses. Collectively, 139 phosphoprotein candidates were identified. Additionally, to broaden the number of phosphorylation sites identified, titanium dioxide phosphopeptide enrichment of trypsin-digested mature pollen crude extract was performed. Thanks to the...
34
Chen, Po Yen, and 陳柏諺. "The study of Photoelectrochemical Reaction in salt-water splitting using p-type Cu-Zn-Sn-S photocathode/n-type Ag-In-S photoanode system." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107CGU05063025%22.&searchmode=basic.