Dissertations / Theses on the topic 'III-Sb'

Les matériaux III-Sb ont prouvé leur potentiel pour la réalisation de composants opto-électroniques dans des domaines aussi variés que les télécommunications ou l'environnement. Cependant, ils restent une filière quasi-inexplorée pour les systèmes photovoltaïques classiques. Dans ce projet de recherche, nous voulons démontrer que les composants à base d'antimoniures sont des candidats prometteurs pour des cellules solaires à haute efficacité et bas coût. Leurs avantages sont multiples : non seulement offrent-ils un large panel d'alliages accordés en maille et des jonctions tunnel à basse résistivité, mais ils permettent aussi une croissance directe sur substrat de Si. Nous étudions donc les briques élémentaires d'une cellule solaire multi-jonction intégrée sur Si. Tout d'abord, nous développons la croissance et fabrication de cellules homo-épitaxiales en GaSb. Les caractéristiques tension-intensité (J-V) mesurées sont proches de l'état de l'art avec une efficacité sous un soleil de 5.9 %. Puis, nous intégrons une cellule à simple jonction GaSb sur un substrat de Si par épitaxie par jet moléculaire (EJM). Les analyses de diffraction X (DRX) et de microscopie à force atomique (AFM) montrent des propriétés de structure et morphologie proches de celles reportées pour des buffers métamorphiques similaires dans la littérature. Nous adaptons alors la configuration de la cellule pour éviter la haute densité de défauts à l'interface GaSb/Si. La cellule hétéro-épitaxiale a une efficacité réduite de 0.6 %. Ce résultat est néanmoins proche des dernières avancées sur les cellules GaSb sur GaAs, et ce, malgré un désaccord de maille plus important. Enfin, nous étudions l'épitaxie d'AlInAsSb. Cet alliage pourrait en théorie atteindre une grande gamme d'énergies de bande interdite tout en restant accordé sur GaSb. Néanmoins, il souffre d'une lacune de miscibilité importante, le rendant sujet à la ségrégation de phase. Il n'y a que peu de mentions de l'AlInAsSb dans la littérature, et toutes rapportent des conditions de croissance instables et des énergies de bande interdite plus basses qu'attendues. Nous réussissons à produire des couches de bonne qualité d'AlInAsSb dont la composition en Al varie de 0.25 à 0.75 et ne présentant aucun signe macroscopique de décomposition de phase. Toutefois, l'observation au microscope à transmission électronique (TEM) révèle des fluctuations de composition nanométriques. Les données de photoluminescence (PL) sont étudiées pour déterminer les propriétés électroniques de l'alliage. Les mesures d'efficacité quantique (QE) montrent que la sous-cellule du haut limite la performance de la cellule tandem. Des modélisations numériques des courbes J-V et QE sont utilisées pour identifier des pistes d'amélioration pour chaque brique élémentaire
III-Sb materials have demonstrated their potential for multiple opto-electronic devices, with applications stretching from communications to environment. However, they remain an almost unexplored segment for classical photovoltaic systems. In this research, we intend to demonstrate that III-Sb-based devices are promising candidates for high-efficiency, low-cost solar cells. Their benefits are two-fold: not only do they offer a wide range of lattice-matched alloys and low-resistivity tunnel junctions, but they also enable direct growth on Si substrates. We thus investigate the building blocks of a GaSb-based multi-junction solar cell integrated onto Si. First, we develop the photovoltaic growth and processing by fabricating homo-epitaxial GaSb cells. Intensity-voltage (J-V) measurements approach the state of the art with 1-sun efficiency of 5.9%. Then, we integrate a GaSb single-junction cell on a Si substrate by molecular beam epitaxy (MBE). X-ray diffraction (XRD) and atomic force microscopy (AFM) analysis show structural and morphological properties close to the best reported in the literature for similar metamorphic buffers. We further adapt the cell configuration to circumvent the high defect density at the GaSb/Si interface. The heteroepitaxial cell results in a reduced efficiency of 0.6%. Nevertheless, this performance is close the most recent advancements on GaSb heteroepitaxial cells on GaAs, despite a much larger mismatch. Last, we investigate the epitaxy of AlInAsSb. This alloy could in theory reach the widest range of bandgap energies while being lattice-matched to GaSb. However, it presents a large miscibility gap, making it vulnerable to phase segregation. AlInAsSb only counts few experimental reports in the literature, all referring to unoptimized growth conditions and abnormally low bandgap energies. We successfully grow good-quality layers with Al composition x_{Al} ranging from 0.25 to 0.75, showing no macroscopic sign of decomposition. Yet, transmission electron microscopy (TEM) observations point to nanometric fluctuations of the quaternary composition. Photoluminescence (PL) data is studied to determine the alloy's electronic properties. We eventually propose and fabricate a tandem cell structure, resulting in 5.2% efficiency. Quantum Efficiency (QE) measurements reveal that the top subcell is limiting the tandem performance. Numerical fits to both J-V and QE data indicate improvement paths for each building block

The activity of a series of polypyridyl compounds 2,2 '-bipyridine (bipy), 1,10-phenanthroline (Phen), dipyrido [3,2-d: 2', 3'-f]quinoxaline (dpq) and dipyrido [3 0.2-a: 2 ', 3'-c]phenazine (dppz) was evaluated in vitro against the promastigote form of Sb(III)-sensitive and resistant Leishmania infantum chagasi and Leishmania amazonensis strains. All compounds were more active than potassium antimony tartrate, used as control drug. The bipy, Phen and dpq showed inhibitory concentration IC50 values in the nanomolar range. Two novel trivalent antimony(III) and bismuth(III) complexes with the nitrogen-donor heterocyclic ligand dipyrido[3,2-a:2',3'-c]phenazine (dppz) were synthesized and characterized as [Sb(dppz)Cl3]·H2O·CH3OH and [Bi(dppz)Cl3]. The crystal structure of Sb(III) complex was determined by X-ray crystallography. These complexes were evaluated for their activity against the promastigote form of Sb(III)-sensitive and resistant Leishmania strains. Both complexes were more effective than dppz alone in inhibiting the growth of Leishmania promastigotes and were at least 77 and 2400 times more active than potassium antimonyl tartrate in Sb(III)- sensitive and -resistant Leishmania, respectively. The cytotoxicity of dppz and its complexes against mouse peritoneal macrophages occurred at dppz concentrations at least 6-fold greater than those found to be active against Leishmania promastigotes. To investigate the role of the metal in the improved antileishmanial activity of dppz, the activity of the Sb(III) complex was compared between the Sb-resistant mutants and their respective parental sensitive strains. The lack of cross-resistance to the Sb(III)-dppz complex together with the much lower activity of antimonyl tartrate, SbCl3 and BiCl3 strongly support the model that the metal is not active by itself but improves the activity of dppz through complexation. Five Sb(III) complexes with 2,2'-bipyridine (bipy), 1,10-phenanthroline (Phen), dipyrido [3,2-d: 2',3'-f]quinoxaline (dpq) were prepared and characterized as: [Sb(bipy)Cl3], [Sb(bipy)Cl2], [Sb(Phen)Cl3], [Sb(Phen)Cl2] e [Sb(dpq)Cl3]. The crystal structures of the complexes with 1,10-phenanthroline were determined for the first time by X ray diffraction. These complexes were evaluated for their activity against Sb(III)-sensitive and resistant Leishmania promastigotes. The leishmanicidal activities of these complexes were higher than those of potassium antimonyl tartrate. All the complexes obtained from the SbCl3 salt were more active than the salt itself. On the other hand, than SbCl2 salt was found to be highly active and more effective than the [Sb(bipy)Cl2] complex. The coordination of Sb (III) caused a significant improvement in the activity of Phen complex against parasites of L. infantum chagasi. Studies of the interaction of these compounds with a peptide model of the zinc finger domain of the HIV-1 NCp7 proteín (KGC), showed that these complexes formed new species with the peptide. Studies of Phen interaction with the Zn(II)-KGC system, indicated that Phen induceds the ejection of Zn(II) from the zinc finger domain.
A atividade da série de compostos polipiridínicos 2,2´-bipiridina (bipy), 1,10-fenantrolina (phen), dipirido[3,2-d:2´,3´-f]quinoxalina (dpq) e dipirido[3,2-a:2',3'-c]fenazina (dppz) foi avaliada contra formas promastigotas, sensíveis e resistentes ao Sb(III), em cepas de Leishmania infantum chagasi e Leishmania amazonensis. Todos os compostos foram mais ativos que o medicamento usado como controle, o tartarato de antimônio e potássio. O grupo bipy, phen e dpq apresentou valores de concentração inibitória CI50 na ordem de nmol L-1, enquanto que os compostos do dppz apresentaram na ordem de µmol L-1. Foram sintetizados e caracterizados por métodos de análises físico-químicos dois compostos inéditos de Sb(III) e Bi(III) com o ligante dipirido[3,2-a:2´,3´-c]fenazina (dppz): [Sb(dppz)Cl3] e [Bi(dppz)Cl3]. As estruturas cristalinas desses complexos foram determinadas por difração de raios X de monocristal. A atividade desses complexos foi avaliada contra formas promastigotas sensíveis e resistentes ao Sb(III) em cepas de Leishmania infantum chagasi e Leishmania amazonensis. A toxicidade do ligante e dos complexos foi avaliada em macrófagos peritoneais de camundongo. Os valores da concentração inibitória CI50 dos complexos em promastigotas de Leishmania foram muito menores que a concentração citotóxica CC50 em macrófagos peritoneais de camundongo. Para o dppz, e os complexos de Bi(III) e Sb(III), o índice de seletividade, calculado como CC50/CI50, foi 12,5, 4,8 e 7,0, respectivamente. Foram preparados e caracterizados por métodos de análises físico-químicos cinco complexos de Sb(III) contendo os derivados polipiridínicos 2,2´- bipiridina (bipy), 1,10-fenatrolina (phen) e dipirido[3,2-d:2´,3´- f]quinoxalina (dpq): [Sb(bipy)Cl3], [Sb(bipy)?Cl2], [Sb(phen)Cl3], [Sb(phen)?Cl2] e [Sb(dpq)Cl3]. As estruturas cristalinas dos complexos da 1,10-fenantrolina foram determinadas pela primeira vez por difração de raios X. A atividade desses complexos foi avaliada contra formas promastigotas sensíveis e resistentes ao Sb(III) em cepas de Leishmania infantum chagasi e Leishmania amazonensis. A atividade leishmanicida de todos os complexos foi muito superior quando comparados com a droga controle, o tartarato de antimônio(III) e potássio . Todos os complexos obtidos a partir do sal SbCl3 apresentaram-se muito mais ativos que o sal. Em contraste, o complexo [Sb(bipy)?Cl2] apresentou menor atividade que o sal ?SbCl2. A coordenação do Sb(III) promoveu melhora significativa da atividade nos complexos da phen contra parasitas de L. infantum chagasi. Os estudos de interação desses complexos com um modelo peptídico derivado da proteína nucleocapsídica NCp7 do vírus HIV (KGC) mostraram a capacidade desses complexos de formar novas espécies com o peptídeo. Os estudos de interação da phen com o sistema Zn(II)-KGC, mostraram a capacidade da phen para ejetar o Zn(II) do domínio dedo de zinco.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
A administração de antimoniais no tratamento da leishmaniose é uma rara oportunidade para estudar o metabolismo de antimônio e das suas espécies químicas. Tais estudos são de grande relevância, uma vez que não se tem conhecimento sobre os metabólitos formados no corpo humano e da sua possível importância na erradicação dos parasitas causadoras da doença, assim como sobre os mecanismos de eliminação deste elemento tóxico. Ao contrário do arsênio, existem poucas metodologias reportadas para a análise de especiação de antimônio em amostras clínicas. O presente trabalho é uma continuação de pesquisas realizadas e publicadas anteriormente, nas quais a técnica de espectrometria de massas (ICPMS) acoplada à cromatografia iônica de alta eficiência IC-(HPLC) foi utilizada para separação e quantificação, em linha, de antimoniato de N-metil glucamina, Sb(V) e Sb(III) em amostras de plasma e urina. Assim, serão apresentados resultados recentes obtidos com o emprego de uma coluna com melhor resolução (Metrosep - A Supp5; 250 mm x 4,0 mm; Metrohm, Suíça) na separação de trimetil antimônio (TMSb), Sb(V) e Sb(III). Testes de otimização mostraram que uma solução de EDTA (0,006 mol L-1, pH 4,7) é adequada como fase móvel para a separação das três espécies. Os tempos de retenção para TMSb, Sb(V) e Sb(III) foram de 44,2 s, 150,6 s e 548,4 s, respectivamente, permitindo uma perfeita e repetitiva (DPR <3 por cento) separação dessas espécies. Repetitividades melhores que 4 por cento foram também obtidas na quantificação das áreas dos três picos cromatográficos correspondentes. Curvas analíticas, construídas a partir de soluções padrão das espécies em solução aquosa e em amostras de urina fortificadas, apresentaram ótima linearidade com coeficientes de correlação maiores que 0,999. Para volumes de amostra de 100 uL, injetados na coluna e utilizando-se o espectrômetro ELAN 5000 (PE-Sciex, EUA) como detector multielementar, em combinação com o nebulizador concêntrico tipo Meinhard e uma câmara ciclônica, limites absolutos de quantificação de 0,02 ng de antimônio foram obtidas para as três espécies estudadas. Testes de estabilidade mostraram que Sb(V) sofre alterações químicas já em intervalos de tempo relativamente curtos (maiores que 8h em água, e que 4h em urina fortificada) enquanto que TMSb e Sb(III) evidenciaram estabilidades consideravelmente maiores em ambos os meios.
Clinical applications of antimonials in the treatment of leishmaniasis are a unique opportunity to study the metabolism of antimony and its species in the human body. As little is known about antimony metabolism, studies are required to improve the knowledge about the excretion mechanism of this toxic element; in particular, those which deal with antimony metabolites and the action of antimonials for the eradication of leishmaniasis causing parasites. In contrast with its chemical analogue arsenic, only a few methods concerning antimony speciation in clinical samples have been described in the literature. The aim of the present work was to improve a method previously developed to separate and quantify N-methyl meglumine antimoniate, Sb(V) and Sb(III) in blood plasma and urine samples by using anion exchange high performance liquid chromatography (IC-HPLC) coupled with inductively-coupled plasma mass spectrometry (ICPMS). Results on the application of an ion chromatography column (Metrosep - A Supp5; 250 mm x 4.0 mm; Metrohm, Swiss) with better resolution for the separation of TMSb, Sb(V) and Sb(III) are presented. The optimum conditions for the separation of the three species were established with 0.006 mol L-1 EDTA at pH 4.7 as the mobile phase. The retention times for TMSb, Sb(V) and Sb(III) were 44,2 s, 151,6 s and 548,4 s, respectively. A robust linear relationship between concentration and peak area was obtained for the three species, both, in aqueous standard solutions and spiked urine samples, with an associated correlation factor higher than 0,999. Relative standard deviations below 4 percent have been obtained in the peak area quantification mode. When using the ELAN 5000 (PerkinElmer-Sciex, EUA) equipped with a concentric Meinhard nebulizer in combination with a cyclonic spray chamber as detector, and employing a 100-uL injection loop in the HPLC system, typical absolute limits of quantification were 0.02 ng of Sb for each of the three antimony species studied. Stability tests showed that Sb(V) suffers chemical alterations within a short time period (>8h in aqueous solutions and >4h in spiked urine), whereas TMSb and Sb(III) presented better stability conditions in both solutions.

This present work discusses the synthesis and characterization of multifunctional di(tri)thiols ligands and their complexes with the pnictogenics elements Sb(III) and Bi(III). In addition, it is reported a brief biological study, especially antibacterial, exhibited by the complexes obtained. Chapter 1 contains a collection of short texts which describe the organosulfured compounds, especially thiols, and compounds of antimony and bismuth and their medicinal properties, besides the epidemiological problems of the ulcer caused by Helycobacter pylori, the leishmaniasis and the bacterial infections. Moreover, it is presented the rationale, the relevance and objectives of the work. In Chapter 2 is presented the results concerning the preparation of the multifunctional di(tri)thiols ligands I: bis(2-tiolethyl)amine, II:bis(2-tiolethyl)ether, III: bis(3-tiolpropyl)sulfide and IV: tris(2-tiolethyl)amine, besides their di(tri)chlorinated and di(tri)isotioureide precursors. All the compounds in question were characterized by conventional techniques such as melting point or boiling point and infrared and nuclear magnetic resonance (1H and 13C) spectroscopy. In Chapter 3 it is described the process of synthesis and characterization of the pnictogenic elements complexes with the ligands obtained with success Ia: Bi{[HN(CH2CH2S)2]Cl}, Ib: {Sb[HN(CH2CH2S)2]Cl}, IIa: {Bi[O(CH2CH2S)2]Cl}, IIb: {Sb[O(CH2CH2S)2]Cl}, IIIa: {Bi[S(CH2CH2CH2S)2]Cl} and IIIb: {Sb[S(CH2CH2CH2S)2]Cl}. The successfully obtained complexes were characterized by techniques like elemental analysis and infrared and multinuclear magnetic resonance (1H, 13C) spectroscopy. The crystal structures of the complexes obtained with the ligand I - Ia and Ib - were also determined by X-ray diffraction. Both series of bismuth and antimony complexes underwent initial evaluation of antibacterial activity , described in Chapter 4 . It is presented initial profiles of growth inhibiting of Gram-positive and Gram-negative bacteria, all of them human pathogens: S. aureus, L. monocytogenes, B. cereus, S. sanguinis, E. coli and S. typhimurium. Finally, Chapter 5 presents the conclusions and the perspectives obtained in the operation of this work, followed by the references and required attachments.
O presente trabalho aborda a síntese e caracterização de ligantes di(tri)tiois multifuncionais e seus complexos formados com os elementos pnictogênicos Sb(III) e Bi(III). Além disso, relata-se um breve estudo biológico, sobretudo antibacteriano, exibido pelos complexos obtidos. O Capítulo 1 contém uma coleção de breves textos que descrevem os compostos organossulfurados, sobretudo os tiois, e os compostos de bismuto e antimônio e suas propriedades medicinais, além dos problemas epidemiológicos da úlcera causada por Helycobacter pilori, da leishmaniose e das infecções bacterianas. Ademais, são apresentadas as justificativas, relevância e objetivos do trabalho. No tocante ao Capítulo 2, são apresentados os resultados referentes à preparação dos ligantes di(tri)tiois multifuncionais I: bis(2-tioletil)amina, II: bis(2-tioletil)éter, III: bis(3-tiolpropil)sulfeto e IV: tris(2-tioletil)amina, além de seus precursores di(tri)clorados e di(tri)isotioureídos. Todos os compostos em questão foram caracterizados por técnicas convencionais como ponto de fusão ou ebulição e espectroscopias na região do infravermelho e de ressonância magnética nuclear (1H e 13C). No Capítulo 3 são descritos os processos de síntese e caracterização de complexos dos elementos pnictogênicos com os ligantes obtidos com sucesso Ia: {Bi[HN(CH2CH2S)2]Cl}, Ib: {Sb[HN(CH2CH2S)2]Cl}, IIa: {Bi[O(CH2CH2S)2]Cl}, IIb: {Sb[O(CH2CH2S)2]Cl}, IIIa: {Bi[S(CH2CH2CH2S)2]Cl} e IIIb: {Sb[S(CH2CH2CH2S)2]Cl}. Os complexos obtidos com sucesso foram caracterizados por técnicas como análise elementar e espectroscopias na região do infravermelho e de ressonância magnética multinuclear (1H, 13C). As estruturas cristalográficas dos complexos inéditos obtidos com o ligante I ¿ Ia e Ib ¿ foram também determinadas por difração de raios X. Ambas as séries de complexos de bismuto e antimônio foram submetidas à avaliação inicial de atividade antibacteriana, descrita no Capítulo 4. São apresentados perfis iniciais de inibição do crescimento de bactérias Gram-positivas e Gramnegativas, todas patógenos ao ser humano: S. aureus, L. monocytogenes, B. cereus, S. sanguinis, E. coli e S. typhimurium. Finalmente o Capítulo 5 apresenta as Conclusões e Perspectivas obtidas com a realização desse trabalho, seguidas das referências bibliográficas e dos anexos necessários.

Le @thème de ce travail est l'étude de la réactivité de complexes oxo de mentaux de transition en milieu réducteur, ainsi que la synthèse et la caractérisation d'hétéropolyoxomolybdates réduits et d'hétéropolyoxovanadates réduits. L'hétéroélement utilisé, As(III) ou Sb(III), présente la particularité de posséder une paire libre susceptible d'induire une stéréochimie originale lors des processus de polycondensation. Les synthèses dites classiques (conditions de température et de pression ordinaires) et les synthèses hydrothermales ont été développées en parallèle pour l'étude des différents systèmes. . .

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A matriz estudada é uma cerâmica a base de Zn7Sb2O12, que possui estrutura do tipo espinélio inverso. A dopagem desta cerâmica com íons TR gera materiais com propriedades diferentes das da fase original que podem apresentar melhor desempenho. Estudos preliminares, onde foram feitas dopagens do tipo Zn7-3xTR2xSb2O12 [TR = Ce(III), Pr(III) e Eu(III)], confirmaram a alta capacidade de absorção dos íons TR nesta estrutura pela manifestação de luminescência destes sistemas saturados. Ademais, as propriedades ópticas das amostras dopadas com Eu(III) auxiliaram na avaliação da ocupação dos íons dopantes na estrutura do Zn7Sb2O12. Assim, o principal objetivo deste trabalho foi a utilização da matriz Zn7Sb2O12 como estrutura hospedeira dos dopantes Eu(III), Pr(III) e Ce(III), estudando suas características estruturais e espectroscópicas e investigando suas potencialidades como material cintilador. Como objetivo secundário, tentou-se confeccionar uma fibra policristalina a partir do material em pó contendo 9% de Eu(III), através da técnica de fusão de zona com laser. A análise estrutural dos sistemas estudados confirmou a formação da fase α-Zn7Sb2O12 e pôde-se identificar uma pequena fração das fases β-Zn7Sb2O12 e Zincita de ZnO, cuja variação foi associada ao tipo do íon dopante. Dados de espectroscopia no IV confirmaram que a ocupação dos dopantes na rede do semicondutor não é substitucional aos sítios de Sb(V) ou Zn(II). Desta forma, a partir da espectroscopia de luminescência, os diversos sítios não substitucionais foram investigados utilizando tanto excitação UV-VIS quanto raios X. No caso do sistema contendo Eu(III) observou-se que, sob excitação via raios X, todos os sítios emitem por meio de um mecanismo...
The matrix studied is a ceramic based on Zn7Sb2O12 with inverse spinel type structure. The doping of this ceramic with RE ions generates materials with different properties from the original phase that can perform better. In preliminary studies the Zn7-3xRE2xSb2O12 [RE = Ce(III), Pr(III) and Eu(III)] doped samples were produced and the high absorption capacity of RE ions in this structure was confirmed due to the manifestation of luminescence of these saturated systems. Moreover, the optical properties of samples doped with Eu(III) showed to be useful to evaluate the occupation of dopant in the Zn7Sb2O12 structure. Thus, the main objective of this study was to use the Zn7Sb2O12 as a host lattice for Eu(III), Pr(III) and Ce(III) as doping ions, the study of their structural and spectroscopic characteristics and the investigation of its potential as a scintillator material. As a secondary objective, we tried to fabricate a fiber from the polycrystalline powder material containing 9% of Eu(III) using the technique of laser floating zone (LFZ). Structural analysis of the studied systems confirmed the formation of Zn7Sb2O12 α-phase and it was also identified a small fraction of the Zn7Sb2O12 β-phase and the Zincita ZnO phase, whose variation was associated with the type of dopant ion. IR spectroscopy data confirmed that the occupation of the semiconductor dopants in the network is not substitutional in relation to Sb(V) or Zn(II) sites. Thus, from the luminescence spectroscopy, the various non-substitutional sites were investigated using both UV-VIS and X-ray excitation sources. In the case of the system containing Eu(III) it was observed that under X-ray excitation all sites emit, that are associated with an intrinsic optical mechanism of the defects generated in the system under that ionizing radiation, while the UVVIS... (Complete abstract click electronic access below)

Resumo: A matriz estudada é uma cerâmica a base de Zn7Sb2O12, que possui estrutura do tipo espinélio inverso. A dopagem desta cerâmica com íons TR gera materiais com propriedades diferentes das da fase original que podem apresentar melhor desempenho. Estudos preliminares, onde foram feitas dopagens do tipo Zn7-3xTR2xSb2O12 [TR = Ce(III), Pr(III) e Eu(III)], confirmaram a alta capacidade de absorção dos íons TR nesta estrutura pela manifestação de luminescência destes sistemas saturados. Ademais, as propriedades ópticas das amostras dopadas com Eu(III) auxiliaram na avaliação da ocupação dos íons dopantes na estrutura do Zn7Sb2O12. Assim, o principal objetivo deste trabalho foi a utilização da matriz Zn7Sb2O12 como estrutura hospedeira dos dopantes Eu(III), Pr(III) e Ce(III), estudando suas características estruturais e espectroscópicas e investigando suas potencialidades como material cintilador. Como objetivo secundário, tentou-se confeccionar uma fibra policristalina a partir do material em pó contendo 9% de Eu(III), através da técnica de fusão de zona com laser. A análise estrutural dos sistemas estudados confirmou a formação da fase α-Zn7Sb2O12 e pôde-se identificar uma pequena fração das fases β-Zn7Sb2O12 e Zincita de ZnO, cuja variação foi associada ao tipo do íon dopante. Dados de espectroscopia no IV confirmaram que a ocupação dos dopantes na rede do semicondutor não é substitucional aos sítios de Sb(V) ou Zn(II). Desta forma, a partir da espectroscopia de luminescência, os diversos sítios não substitucionais foram investigados utilizando tanto excitação UV-VIS quanto raios X. No caso do sistema contendo Eu(III) observou-se que, sob excitação via raios X, todos os sítios emitem por meio de um mecanismo... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The matrix studied is a ceramic based on Zn7Sb2O12 with inverse spinel type structure. The doping of this ceramic with RE ions generates materials with different properties from the original phase that can perform better. In preliminary studies the Zn7-3xRE2xSb2O12 [RE = Ce(III), Pr(III) and Eu(III)] doped samples were produced and the high absorption capacity of RE ions in this structure was confirmed due to the manifestation of luminescence of these saturated systems. Moreover, the optical properties of samples doped with Eu(III) showed to be useful to evaluate the occupation of dopant in the Zn7Sb2O12 structure. Thus, the main objective of this study was to use the Zn7Sb2O12 as a host lattice for Eu(III), Pr(III) and Ce(III) as doping ions, the study of their structural and spectroscopic characteristics and the investigation of its potential as a scintillator material. As a secondary objective, we tried to fabricate a fiber from the polycrystalline powder material containing 9% of Eu(III) using the technique of laser floating zone (LFZ). Structural analysis of the studied systems confirmed the formation of Zn7Sb2O12 α-phase and it was also identified a small fraction of the Zn7Sb2O12 β-phase and the Zincita ZnO phase, whose variation was associated with the type of dopant ion. IR spectroscopy data confirmed that the occupation of the semiconductor dopants in the network is not substitutional in relation to Sb(V) or Zn(II) sites. Thus, from the luminescence spectroscopy, the various non-substitutional sites were investigated using both UV-VIS and X-ray excitation sources. In the case of the system containing Eu(III) it was observed that under X-ray excitation all sites emit, that are associated with an intrinsic optical mechanism of the defects generated in the system under that ionizing radiation, while the UVVIS... (Complete abstract click electronic access below)
Orientador: Ana Maria Pires
Coorientador: Marian Rosaly Davolos
Banca: Silvania Lanfredi
Banca: Marco Antonio Utrera Martines
Mestre

The ejection of zinc from its coordination site in Zn-finger protein can be promoted by other metal species through competitive binding. This is considered as a promising strategy to inactivate the Zn-finger protein and for the design of new and more efficient drugs. A study of the As(III) interaction with the CCHC zinc finger domain of the NCp7 protein of HIV-1 has been carried out using the fluorescence and circular dichroism spectroscopies. This study allowed a better understanding of the ability of As(III) to promote Zn ejection and brought new insights into the role of glutathione as a biomolecule that can facilitate the ejection of Zn. The exactly mechanism is not yet known, but the fluorescence and circular dichroism data shows the importance of the participation of glutathione in the system formed. The competition between As(III) and Zn(II) was evaluated in phosphate buffers of different pHs. Sb(III) and Bi(III) compounds with 2-mercapto-imidazole- and -mercapto-benzimidazole-type ligands have been synthesized. These complexes involve coordination of the metal specie with the S-atom from thiol group and the N-atom from imidazole, just like occurs in the zinc finger domains. Five new complexes, SbCl(Bzmiz)2.CH3OH, BiCl(Bzmiz).CH3OH, BiCl2(Bzmiz).2H2O, SbCl2(Miz) and BiCl2(Miz) were successfully obtained. Physico-chemical characterization was performed using NMR, FTIR and UV-vis spectroscopies, elementar analyses, conductimetric analyses and thermogravimetric analyses. Four crystals were also obtained from these complexes, except for the SbCl2(Miz) complex. X-Ray diffraction analyses of these crystals are in course.
A ejeção do zinco promovida pela sua competição com outra espécie metálica pelo sítio de coordenação da proteína é tida como uma estratégia de inativação da proteína podendo possivelmente ser aplicada para síntese de novos fármacos mais eficazes. O estudo da interação do As(III) com modelo de peptídeo dedo de zinco CCHC da proteína NCp7 de HIV-1 foi realizado utilizando-se as técnicas espectroscópicas de fluorescência e dicroísmo circular. Esse estudo permitiu uma melhor compreensão sobre a habilidade do As(III) de promover a ejeção do Zn e o papel da glutationa como biomolécula facilitadora na ejeção do zinco. O exato mecanismo ainda não é conhecido, mas os dados de fluorescência e dicroísmo circular obtidos nos mostraram a importância da participação da glutationa no sistema formado. A competição entre As(III) e Zn(II) foi avaliada em diferentes pHs em tampão fosfato. Foram sintetizados compostos de Sb(III) e Bi(III) com os ligantes 2-mercapto-imidazol e 2-mercapto-benzimidazol. Os complexos envolvendo tais ligantes conservam como característica a coordenação da espécie metálica com S de grupo tiol e N de imidazol, assim como ocorre em domínios dedos de zinco. Obtivemos como resultados das sínteses, cinco complexos inéditos, bCl(Bzmiz)2.CH3OH, BiCl(Bzmiz).CH3OH, BiCl2(Bzmiz).2H2O, SbCl2(Miz) e BiCl2(Miz). A caracterização físico-química desses complexos foi feita por RMN, espectroscopias FTIR e UV-Vis, análises elementar (CHN), condutimetria e termogravimetria. Foram obtidos cristais de quatro dos cinco compostos sintetizados, não obtendo cristais apenas para o complexo SbCl2(Miz). Estudos de difração de raios X estão em andamento.

In this work, the electronic band structure of III (In, Al, Ga) - V (N, As, Sb) compounds and their ternary alloys have been investigated by density functional theory (DFT) within generalized gradient approximation (GGA) and empirical tight binding (ETB) calculations, respectively. The present DFT-GGA calculations have shown direct band gap structures in zinc-blende phase for InN, InAs, InSb, GaN, and GaAs. However, indirect band gap structures have been obtained for cubic AlN, AlSb and AlAs com- pounds
here, the conduction band minima of both AlN and AlAs are located at X symmetry point, while that of AlSb is at a position lying along Gamma- X direction. An important part of this work consists of ETB calculations which have been parameterized for sp3d2 basis and nearest neighbor interactions to study the band gap bowing of III(In
Al)- V(N
As
Sb) ternary alloys. This ETB model provides a satisfactory electronic properties of alloys within reasonable calculation time compared to the calculations of DFT. Since the present ETB energy parameters reproduce successfully the band structures of the compounds at ¡
and X symme- try points, they are considered reliable for the band gap bowing calculations of the ternary alloys. In the present work, the band gap engineering of InNxAs1¡
x, InNxSb1¡
x, InAsxSb1¡
x, Al1¡
xInxN, Al1¡
xInxSb and Al1¡
xInxAs alloys has been studied for total range of constituents (0 <
x <
1). The downward band gap bowing seems the largest in InNxAs1¡
x alloys among the alloys considered in this work. A metallic character of InNxAs1¡
x, InNxSb1¡
x and InAsxSb1¡
x has been ob- tained in the present calculations for certain concentration range of constituents (N
As) as predicted in the literature. Even for a small amount of contents (x), a decrease of the electronic e®
ective mass around ¡
symmetry point appears for InNxAs1-x, InNxSb1-x and InAsxSb1-x alloys manifesting itself by an increase of the band curvature. The calculated cross over from indirect to direct band gap of ternary Al alloys has been found to be consistent with the measurements. As a last summary, the determinations of the band gaps of alloys as a function of contents, the concentration range of con- stituents leading to metallic character of the alloys, the change of the electronic effective mass around the Brillioun zone center (Gamma) as a function of alloy contents, the cross over from indirect to direct band gap of the alloys which are direct on one end, indirect on the other end, are main achievements in this work, indispensable for the development of mate- rials leading to new modern circuit components.

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In this work the properties of the Sb(III) and Bi(III) complexes with mesoionic 1,3-thiazolium-5-thiolates and derivatives of the 1,3,5-triazine have been investigate from theoretical and experimental perspectives. This thesis was divided in three parts. In the first part, the performance of the semiempirical methods was assessed regarding to the prediction of the geometries of 54 Sb(III) complexes and 75 of Bi(III) with ligands, macrocyclic, heterocyclic, amine carboxylate tiocompounds and organometallic. The results indicated that AM1 and PM3 correctly predict the geometries of Sb complexes. PM6 is more accurate to predict the geometries of both Sb and Bi tiocompounds. However, PM6 presented an inability to reproduce the geometries of complexes with Sb−N bonds. In general, PM6 is more accurate to Bi complexes. In the second part, a theoretical and experimental study of Sb(III) and Bi(III) complexes with mesoionic 1,3-thiazólio-5-thiolates ligands has been performed. Five new complexes of formulas [Sb4Cl12(M1)3], [SbCl3(M2)]·H2O, [Bi4Cl12(M1)3], [Bi4Br12(M1)3] and [Bi4Br12(M2)3] have been synthesized and characterized by elemental analysis, IR, 13C NRM and conductivity measurements. Both complexes and mesoionic ligands were studied for their antimicrobial activity against species of bacteria Estafilococos aureus and fungi C. albicans, C. tropicalis, C. krusei. Sb complexes and their corresponding mesoionic ligands exhibited active against all the bacteria and fungi with minimum inhibitory concentration (MIC) in the range 256-1024 μg/mL. On the other hand, the Bi complexes not exhibit such activities. The theoretical study of the ground state geometries, electronic structures, thermodynamic stabilities and chemical bonds of the complexes [MX3(L)] (X = F, Cl, Br, L= M1, M2, M3) in gas phase have been carried out at DFT and MP2 theoretical level. Potential energy curves (PECs) were calculated using B3LYP, M06-2X and MP2 level of theory with 6-31G basis set for all element, except Sb and Bi which we applied the 6-31G(d) basis set coupled to relativistic pseudopotentials. The PECs calculated with MP2 and M06-2X indicated that the minima structures are stable by multiple intramolecular interactions. The analysis considering NBO charges indicated which the metal coordination led to the loss of mesoionic character, producing large charge delocalization in the ring. The analysis considering the frontier molecular orbitals calculated at M06-2X/cc-pVTZ pointed out a large contribution from atomic orbitals of the exocyclic sulfur and metal atoms to HOMO. However, the atomic orbitals of the metal did not contribute to LUMO, suggesting a process of charge transfer metal to ligand. QTAIM study of the complexes have pointed out that the metal-sulfur bonds are closed shell, with small degree of electron sharing. Besides, the QTAIM study has indicated the intramolecular interactions as hydrogen bonds, halogen bonds and metal-π interactions. In the final part of this thesis, we have been synthesized the complexes [SbCl3(TMT)], [Sb3Cl9(TMT)2], [Bi3Cl9(TMT)2], [Sb2Cl6(PIPT)]·4H2O, [Bi2Cl6(PIPT)]·2H2O and characterized them by elemental analysis, IR, 13C NRM and thermal analysis. Biological activities of both triazines and their complexes with Sb and Bi against bacteria E. aureus and fungi C. albicans, C. tropicalis, C. krusei have been obtained. Sb complexes exhibited activities against all bacteria and fungi with CIM ranging in the interval of 512-1024 μg/mL. Both triazine ligands and their bismuth compounds did not exhibit such activities.
Nesse trabalho as propriedades dos complexos Sb(III) e Bi(III) com ligantes mesoiônicos do núcleo 1,3-tiazólio-5-tiolato e derivados da 1,3,5-triazina foram investigadas a partir de perspectivas teóricas e experimentais. O estudo foi dividido em três partes. Na primeira etapa foi avaliado a qualidade dos métodos semiempíricos na predição das geometrias de 54 complexos de Sb(III) e 75 de Bi(III) com ligantes macrocíclicos, heterocíclicos, aminocarboxilatos, tiocompostos e organometálicos. Os resultados indicam que o AM1 e PM3 predizem corretamente as geometrias dos complexos de Sb. O PM6 é mais exato para os tiocompostos de Sb e Bi. No entanto, falha na predição das estruturas dos complexos com ligações Sb−N. De modo geral, o PM6 é mais exato para os complexos de Bi. Na segunda parte, foi realizado um estudo teórico-experimental de complexos de Sb(III) e Bi(III) com os ligantes mesoiônicos da classe 1,3-tiazólio-5-tiolato. Para isso, foram sintetizados cinco novos complexos de fórmula [Sb4Cl12(M1)3], [SbCl3(M2)]·H2O, [Bi4Cl12(M1)3], [Bi4Br12(M1)3], [Bi4Br12(M2)3] e caracterizados por análise elementar, espectroscopia de absorção no infravermelho, RMN 13C e medidas de condutância. A atividade antimicrobiana in vitro dos complexos e ligantes mesoiônicos foi avaliada contra as espécies de bactérias Estafilococos aureus e fungos Candida albicans, C. tropicalis, C. krusei. Os complexos de Sb e mesoiônicos foram ativos contra todas as cepas estudadas, com CIM da faixa de 256-1024 μg/mL. Por outro lado, os compostos de Bi não foram ativos. O estudo teórico das geometrias do estado fundamental, estruturas eletrônicas, estabilidades termodinâmicas e ligações químicas dos complexos [MX3(L)] (X = F, Cl, Br, L= M1, M2, M3) em fase gasosa foi realizado. As curvas de energia potencial (CEP) dos complexos foram calculadas a nível MP2, DFT/B3LYP e M06-2X com o conjunto de base 6-31G para os elementos mais leves e 6-31G(d) para o Sb e Bi com pseudopotenciais relativísticos. As CEP calculadas a nível MP2 e M06-2X indicam que as estruturas de menor energia dos complexos são estabilizadas por múltiplas interações intramoleculares. O estudo estrutural e a análise das cargas NBO nos complexos indica que a coordenação resulta na quebra do caráter mesoiônico, permitindo uma maior deslocalização de cargas no anel. A análise dos orbitais moleculares de fronteira dos complexos calculados a nível M06-2X/cc-PVTZ, mostra uma grande contribuição dos orbitais atômicos do átomo de enxofre exocíclico e dos metais, para o HOMO. No entanto, os metais não contribuem para o LUMO, indicando a possibilidade de transições por transferência de carga metal-ligante. O estudo QTAIM dos complexos, define as ligações metal-enxofre como de camada fechada, com um pequeno grau de compartilhamento de elétrons. Além disto, o estudo QTAIM também caracterizou as interações intramoleculares como: ligações de hidrogênio, ligações de halogênio e interações do tipo metal-π. Na etapa final deste trabalho, foram sintetizados os complexos [SbCl3(TMT)], [Sb3Cl9(TMT)2], [Bi3Cl9(TMT)2], [Sb2Cl6(PIPT)]·4H2O, [Bi2Cl6(PIPT)]·2H2O e caracterizados por análises elementar, espectroscopia de infravermelho, RMN 13C e análise termogravimétrica. A atividade biológica dos ligantes triazínicos e complexos foi avaliada contra as bactérias do gênero Estafilococos e fungos C. albicans, C. tropicalis e C. krusei. Os complexos de Sb foram ativos contra todas as espécies e bactérias e fungos com CIM na faixa de 512-1024 μg/mL. Os ligantes triazínicos e complexos de Bi não apresentaram atividade antimicrobiana.

Le développement des systèmes de conversion photovoltaïques ces trente dernières années a permis des améliorations considérables en terme de coût et de performances. A ce jour, les meilleurs rendements de conversion photovoltaïques sont obtenus avec des systèmes à oncentration solaire utilisant des cellules multi-jonctions (MJ) à base de matériaux semi-conducteurs III-V. Dans ce domaine, le meilleur rendement atteint à ce jour est de 46,0 % sous une concentration de 508 soleils avec une cellule à 4 jonctions issu du partenariat Soitec/Fraunhofer ISE/CEA. Cette cellule MJ est composée d’une cellule tandem accordée sur GaAs assemblée par collage moléculaire à une autre cellule tandem accordée sur InP. Bien que le rendement atteint soit élevé, les performances de la cellule sont limitées sous fortes concentrations à cause de ce collage moléculaire. Dans le domaine des fortes concentrations, le record est actuellement détenu par la société américaine Solar Junction avec un rendement de 44,0 % mesuré sur une cellule triple jonction monolithique en GaInP/GaAs/GaInNAs de 0,3 cm² pour un taux de concentration de 942 soleils (irradiance directe de 942 kW/m²). Une seconde cellule a atteint un rendement performant à une irradiance directe supérieure à 1 MW/m², il s’agit d’une cellule tandem en GaInP/GaAs de l’IES-UPM qui a atteint 32,6 % sous une concentration de 1026 soleils.Dans le contexte précédent, les travaux présentés dans ce manuscrit visent à l’évaluation d’une nouvelle filière dans le domaine du CPV à base de semi-conducteurs III-V : la filière antimoniure (III-Sb). Les cellules que nous avons étudiées dans le cadre de cette thèse sont à base de GaSb et de l’alliage AlxGa1-xAsySb1-y, fabriquées de façon monolithique par MBE (Molecular Beam Epitaxy) sur substrat GaSb. Ce type de cellules, du fait de la très bonne complémentarité des gaps des matériaux, constitue une alternative crédible et originale aux cellules existantes pour une utilisation sous flux solaire fortement concentré.Le travail à réaliser dans le cadre de cette thèse porte sur :- La caractérisation électrique et optique des alliages quaternaires utilisés.- La conception et le design des cellules.- La réalisation et la mise au point de toutes les étapes technologiques nécessaires à la conception des cellules (photolithographie UV, gravure, métallisation, …).- La caractérisation électrique et optique des cellules fabriquées (I(V), TLM, réponse spectrale, …).- La caractérisation des cellules sous flux solaire (fortement) concentré.Ce travail a été cofinancé par l’Université de Montpellier et le LabEx SOLSTICE
The development of photovoltaic conversion systems these past thirty years led to considerable improvements in terms of cost and performances. The best conversion efficiencies are currently obtained with solar concentration systems associated with multi-junction solar cells (MJSC) made of III-V materials. In this field, the record efficiency is of 46.0% under a 508-sun solar concentration with a 4-junction cell from Soitec/Fraunhofer ISE/CEA. This MJSC is composed of a tandem cell lattice-matched to GaAs wafer bonded to another tandem cell lattice-matched to InP. Although it reached high conversion efficiency, its performances are limited under solar concentration because of the wafer bonding. In the field of high solar concentrations, the record is held by Solar Junction with a monolithic triple junction GaInP/GaAs/GaInNAs cell of 0.3 cm² that reached an efficiency of 44.0% under 942 suns (direct irradiance of 942 kW/m²). Another high solar concentration efficiency record worth mentioning is held by IES-UPM with a tandem solar cell (GaInP/GaAs) that reached an efficiency of 32.6% under a concentration of 1026 suns.In this context, the work presented in this manuscript aims to evaluate the potential of a new family of III-V materials for high solar concentration applications: antimonide-based materials (III-Sb). The studied cells in this thesis are made out of GaSb and the quaternary AlxGa1-xAsySb1-y, monolithically grown by MBE (Molecular Beam Epitaxy) on a GaSb substrate. These materials, thanks to the large range of available band-gaps, represent an original and well-founded alternative to existing solar cells for high solar concentration applications.The work achieved in this thesis covers:- The electrical and optical characterization of the quaternary materials used.- The conception and designing of the cells.- The production and tuning of every technological steps in order to fabricate our solar cells (UV photolithography, etching, metal deposition,…).- The electrical and optical characterization of our fabricated solar cells (I(V), TLM, spectral response,…).- The characterization under (high) solar concentration of our cells.This work was cofounded by the University of Montpellier and the LabEx SOLSTICE

Premilere partie: la plupart des phases du titre ont une structure en couches voisine de celle de zrp-alpha. Le traitement en milieu acide des phases en couches km**(i)(po::(4))::(2), m=sb, ta permet d'obtenir les acides correspondant hm**(v)(po::(4))::(2)xh::(2)o. Un autre acide, hta(po::(4))::(2) 3d, peut etre obtenu directement par voie seche, description de sa structure tridimensionnelle. Determination de la teneur en eau, de la structure et du comportement thermique de ces differents acides dont la thermolyse conduit a des phases originales qui sont etudiees. Seconde partie: dans la premiere famille, les phases (m'**(iii)::(1/2)m**(v)::(3/2)) (po::(4))::(3) sont de type nasicon ou sc::(2)(no::(4))::(3) ou d'un nouveau type structural, dans la seconde, les phases m'**(iii)::(1/2)m**(v)::(1/2))p::(2)o::(7) presentent des structures voisines de celle de zrp::(2)o::(7)

La conversion photovoltaïque (PV) de l’énergie solaire repose sur la capacité qu’ont certains matériaux à convertir l’énergie des photons en courant électrique. Le développement des systèmes de conversion PV ces trente dernières années a permis des améliorations considérables en terme de coût et de performances dans le domaine des énergies renouvelables.Une cellule multi-jonctions (MJ), à base de matériaux semi-conducteurs III-V, est un empilement de sous-cellules aux gaps décroissants qui permet notamment une plus large utilisation du spectre solaire. Soumettre ces cellules PV à un flux solaire concentré permet d’augmenter significativement la puissance électrique créée par celles-ci, et ainsi d’abaisser substantiellement le coût de l’électricité produite.Le record du monde est actuellement détenu par le partenariat Soitec / Fraunhofer ISE avec un rendement de 46,0 % mesuré sur une cellule quadruple-jonctions en GaInP/GaAs//InGaAsP/InGaAs pour un taux de concentration de 508 X (où 1 X =1 soleil = 1 kW/m²).L’objectif du travail réalisé dans le cadre de cette thèse est de proposer une alternative aux cellules existantes plus simple à mettre en œuvre avec des cellules MJ monolithiques accordées sur substrat de GaSb pour des concentrations solaire de 1 000, soit une irradiance directe de 1 MW/m². Ce type de cellules, du fait de la très bonne complémentarité des gaps des matériaux et ses alignements de bandes favorables, constitue une alternative crédible et originale aux cellules existantes pour une utilisation sous flux solaire fortement concentré.Afin de mieux comprendre la cellule multijonctions III-Sb optimale, les travaux réalisés ont porté sur la fabrication et la caractérisation des trois sous-cellules fabriquées indépendamment. Ces trois échantillons épitaxiés sont l’Al0,9Ga0,1As0,07Sb0,93 (cellule Top), l’Al0,35Ga0,65As0,03Sb0,97 (cellule Middle) et le GaSb (cellule Bottom) ayant comme gaps respectifs 1,6 eV, 1,22 eV et 0,726 eV à 300 K.Le travail présenté dans cette thèse porte sur :- La réalisation et la mise au point de toutes les étapes technologiques nécessaires à la fabrication des cellules (dépôts métalliques, gravure humide et sèche par plasma …).- La caractérisation des métallisations par structure TLM (Transmission Line Method) dont le meilleur résultat obtenu concerne une métallisation tri-couche Cr/Pd/Au (30/30/30 nm) sur substrat GaSb type P.- La caractérisation sous obscurité courant-tension des paramètres électriques des cellules PV à température ambiante et en fonction de la température.- La caractérisation thermique par mesure de la conductivité thermique des matériaux et une cartographie de température de surface en fonction du flux solaire concentré en conditions réelles.- La caractérisation électro-optique par réponse spectrale, à partir de laquelle nous avons calculé le rendement quantique externe qui représente le rapport entre la quantité d’électrons créés et la quantité de photons incidente.- La caractérisation sous illumination à 1 soleil (1 000 W/m²) sous simulateur solaire et en conditions solaire dont nous avons comparé les paramètres électriques.- La caractérisation des cellules sous flux solaire (fortement) concentré au laboratoire PROMES. Les meilleurs rendements obtenus pour les cellules PV Bottom, Middle et Top respectifs de 4,6 % à 40 X (proche de l’état de l’art), 8,2 % à 96 X et 5,4 % à 185 X (première mondiale pour ces matériaux quaternaires).Ce travail a été cofinancé par le Ministère de l’Education et de la Recherche (Allocation ED) et le Labex SOLSTICE.Photovoltaic (PV) solar energy consists on the ability of certain materials to convert the photon energy into electric current. The development of PV conversion systems in the past thirty years has led to considerable improvements in terms of cost and performance in the field of renewable energies
Photovoltaic (PV) solar energy consists on the ability of certain materials to convert the photon energy into electric current. The development of PV conversion systems in the past thirty years has led to considerable improvements in terms of cost and performance in the field of renewable energies.A multi-junction (MJ) cell, based on III-V semiconductor materials, is a stack of sub-cells with decreasing gaps which notably allows wider use of the solar spectrum. Exposing these PV cells to a concentrated solar flux can significantly increase the electrical power generated, and therefore substantially lower the cost of electricity yielded.The world record is currently held by the partnership Soitec / Fraunhofer ISE with an efficiency of 46.0 % measured on a four-junction cell GaInP/GaAs//InGaAsP/InGaAs for a concentration ratio of 508 X (where 1 X = 1 sun = 1 kW/m²).The objective of the work in this thesis is to propose an alternative to existing cells, easier to implement with monolithic MJ cells grown on a GaSb substrate for solar concentrations of 1 000, which corresponds to a direct irradiance of 1 MW/m². This type of cell, due to the good complementary of the material gaps and its favorable band alignments, is a realistic and original alternative to existing cells for use under highly concentrated solar flux.To better understand the optimal multijunction III-Sb cell, the work carried out consisted on the manufacturing and characterization of the three sub-cells independently.These three epitaxial samples are Al0,9Ga0,1As0,07Sb0,93 (Top cell), the Al0,35Ga0,65As0,03Sb0,97 (Middle cell) and GaSb (Bottom cell) having as respective gaps 1.6 eV, 1.22 eV and 0.726 eV at 300 K.The work presented in this thesis is:- The establishment of all the technological steps required to manufacture the cells (metal deposition, wet and dry plasma etching ...).- The characterization of metallization by TLM structure (Transmission Line Method) with the best result being a three-layer metallization Cr/Pd/Au (30/30/30 nm) on a GaSb P-type substrate.- The characterization under dark of current-voltage electrical parameters of PV cells at room temperature and in function of the temperature.- The thermal characterization by measuring the thermal conductivity of the materials and a surface temperature mapping in function of the concentrated solar flux in realistic conditions.- The electro-optical characterization by spectral response, from which we calculated the external quantum efficiency which is the ratio between the amount of electrons created and the amount of incident photons.- The characterization under 1 sun illumination (1 000 W/m²) in a solar simulator and in realistic conditions of which we compared the electrical parameters.- The characterization of solar cells under (highly) concentrated solar flux in the PROMES laboratory.The best efficiencies for Bottom, Middle and Top PV cells respectively are 4.6 % for 40 X (close to the state of the art), 8.2 % for 96 X and 5.4 % for 185 X (world first for these quaternary materials).This work was cofounded by the Ministry of Education and Research (ED Research grant) and Labex SOLSTICE

Ce travail concerne l'étude d'un élément Hall de performances intéressantes, et réalisé en technologie couche mince. L'analyse bibliographique nous a conduit à privilégier l'antimoniure d'indium. L'ouvrage, après examen critique des techniques de fabrication de couches minces composées, présente la nouvelle méthode que nous avons développée ainsi que les procédés mis en oeuvre pour optimiser les caractéristiques structurelles des couches. Les résultats expérimentaux concernant l'analyse structurelle, les procédures de recuit et le comportement électrique en présence de champ magnétique des couches de InSb sont présentés. Les perspectives d'avenir sont évoquées en conclusion

Les progrès réalisés au cours des trente dernières années dans les domaines de la croissance cristalline et de la technologie des semiconducteurs III-V ont permis aux composants optoélectroniques (lasers, détecteurs) fonctionnant dans la bande 0,4-1,8 µm d'être de nos jours des éléments essentiels pour les télécommunications, le stockage des données ou le domaine médical. Cependant, de nombreuses applications, comme la détection infrarouge, la spectroscopie moléculaire de polluants atmosphériques, nécessitent le développement de lasers et de détecteurs fonctionnant à plus grande longueur d'onde, notamment dans les fenêtres de transparence atmosphériques (3-5 µm et 8-12 µm). La réalisation de ces différents dispositifs est possible en utilisant les hétérostructures mixtes antimoniures/arséniures. Cependant, plusieurs difficultés sont associées à la croissance épitaxiale de ces hétérostructures (désaccords de maille entre les différents matériaux considérés, caractérisation des hétérostructures, incorporation compétitive des différents éléments V As et Sb...).
L'objet de cette thèse a consisté, dans un premier temps, à déterminer les conditions de croissance permettant la réalisation des lasers à cascade quantique basés sur le système de matériaux AlAsSb/GaInAs épitaxié sur substrat d'InP et de détecteurs photovoltaïques InAsSb épitaxiés sur substrat de GaSb. Pour ce faire, l'ensemble des paramètres intervenant dans l'incorporation concurrentielle des deux éléments V As et Sb (température, vitesse, nature de l'élément III...) a été étudié. Une procédure de détermination des épaisseurs individuelles et des compositions des hétérostructures GaInAs/AlAsSb, par diffraction de rayons X, basée sur l'utilisation d'un double superréseau a également été proposée. Ce travail a permis de mieux comprendre les phénomènes intervenant aux interfaces selon les conditions de croissance utilisées et d'obtenir ainsi un calibrage rigoureux et reproductible. Des résultats préliminaires satisfaisants ont finalement été obtenus sur les diodes électroluminescentes AlAsSb/GaInAs à cascade quantique sur InP ainsi que sur les détecteurs photovoltaïques InAsSb sur GaSb.
La seconde partie de cette thèse a consisté en l'optimisation des conditions de croissance des hétérostructures (Al,Ga)Sb/InAs épitaxiées sur substrat d'InAs et de GaSb. Dans ce système de matériaux, l'existence d'une ségrégation d'indium aux interfaces AlSb/InAs a pu être mise en évidence par différentes techniques de caractérisation (HRTEM, RHEED, HRXRD). La prise en compte de cette ségrégation a permis d'améliorer les performances des LCQs InAs/AlSb et d'atteindre le fonctionnement à température ambiante. Des résultats prometteurs ont également été obtenus pour des structures détectrices interbandes à cascade GaSb/AlSb/InAs.

The coordination chemistry of antimony(III) and antimony(V) have been investigated to reveal fundamental structural and electronic features. The limited scope of known cationic antimony(V) complexes was greatly expanded, including the first examples of pnictogen(V) trications. The systematic nature of these investigations led to the observation of redox chemistry, determined to be the result of reductive elimination of chlorobenzene and biphenyl from an antimony center. The reactivity of [Ph2Sb(OPyrMe)4][OTf]3 was investigated and it was found that the OPyrMe ligands are sufficiently labile to perform ligand substitution chemistry. However, when exposed to phosphines, ligand-centered reactivity prevails and phosphonium salts of the form [R3P(2-4-methylpyridine)][OTf] which may be useful reagents in the field of medicinal chemistry and drug design. While attempts were made to synthesise antimony(V) tetra- and penta- cations have been unsuccessful, the methodologies reported here will serve as a foundation to future endeavors.
Graduate
2019-08-31

The HSO₃F/SbF₅ system (“Magic Acid”) was investigated by high resolution ¹⁹F 1D and 2D NMR (COSY and J-resolved). Twelve fluoro-fluorosulfato-antimonate(V) species were clearly identified and the relative concentrations of these species were estimated based on the integration of the ¹⁹F NMR signals for the HSO₃F/SbF₅ systems with SbF₅ concentration ranging from X[sub SbF₅]=0.000999 to X[sub SbF₅]=0.342. The 1:1 and 1:2 complexes between HSO₃F and SbF₅, [SbF₅(HSO₃F)]⁻ and [Sb₂F₁₀(μ-SO₃F)⁻, were found to be the principal species in the system. Other constituent species including the monomers, [SbF₆]⁻,[SbF₄(SO₃F)₂], [SbF₃(SO₃F)₃]⁻ as well as the dimers, [Sb₂F₁₁], [Sb₂F₉(μ-SO₃F)₂]⁻, and [Sb₂F₈(μ-SO₃F)(SO₃F)₂]⁻, were also found in the HSO₃F/SbF₅ system. Trimers of the type [SbF₅-(μ-SO₃F)-SbF₄-(μ-SO₃F)-SbF₅]⁻ are present in systems with X[sub SbF₅]≥0.0989. All the oligomeric fluoro-fluorosulfato-antimonate(V) species were found to be SO₃F-bridged rather than F-bridged. Based on the relative concentrations of the species in the HSO₃F/SbF₅ system, it appears that solvolysis of SbF₅ in HSO₃F is likely to occur in addition to the ligand redistribution. The byproduct HF reacts with SiO₂ to produce H₂0, which is protonated to give the oxonium ion H₃O⁺, which was observed in ¹H NMR spectra of the system. An oxonium salt [H₃O][Sb₂F₁₁] was crystallized from the HSO₃F/SbF₅ system with high SbF₅ content (x[sub SbF₅]≥0.342). The structure of[H₃O][Sb₂F₁₁] is determined by single crystal X-ray diffraction. It has a very complex structure and the asymmetrical O-H⋅⋅⋅F hydrogen bonds link H₃O⁺ and [Sb₂F₁₁] ions to form a 3-dimension network. Two new Sb(III) compounds, [SbF₂(SO₃F)][sub x] and [SbF(SO₃F)₂][sub x], as well as [Sb(SO₃F)₃][sub x], were prepared and their polymeric structures were determined to high precision by single crystal X-ray diffraction. A detailed comparison for the series [SbF{sub n}(SO₃F){sub 3-n}][sub x] (n = 0, 1, 2, or 3) provides an insight into the complex coordination chemistry of Sb(III) fluoride fluorosulfates. Fluoride functions as an asymmetrical bridging ligand and fluorosulfate functions as an 0-tridentate asymmetrical bridging ligands. The overall coordination number of antimony depends on the available donor sites of the ligands and accordingly increases gradually from six for SbF₃ to nine for [Sb(SO₃F)₃][sub x].The Sb-O and Sb-F interactions in all four compounds span a wide range from normal covalent bonds (1.9∼2.1 Å) to long intermolecular contact (∼ 3.0 Å). In order to obtain structural information on superacid anions, single crystals of CsSO₃F, Cs[H(SO₃F)₂], Cs[Au(SO₃F)₄],Cs₂[Pt(SO₃F)₆],and Cs[Sb(SO₃F)₆] were prepared and their crystal structures were determined by single crystal X-ray diffraction. The structures of the superacid anions are correlated to the weak nucleophilicity of anions and hence the acid strength of the corresponding conjugate superacids. The new superacid anion [Sb(SO₃F)₆]⁻ is highly symmetric and has exceptionally short S-O and S-F bonds at the periphery of the anion, From the structure of the anion, it is suggested that [Sb(SO₃F)₆]⁻ should be very weakly nucleophilic. The corresponding conjugate superacid, the HSO₃F/Sb(SO₃F)₅ system, should be a very strong superacid system.

abstract: Photovoltaic (PV) energy has shown tremendous improvements in the past few decades showing great promises for future sustainable energy sources. Among all PV energy sources, III-V-based solar cells have demonstrated the highest efficiencies. This dissertation investigates the two different III-V solar cells with low (III-antimonide) and high (III-nitride) bandgaps. III-antimonide semiconductors, particularly aluminum (indium) gallium antimonide alloys, with relatively low bandgaps, are promising candidates for the absorption of long wavelength photons and thermophotovoltaic applications. GaSb and its alloys can be grown metamorphically on non-native substrates such as GaAs allowing for the understanding of different multijunction solar cell designs. The work in this dissertation presents the molecular beam epitaxy growth, crystal quality, and device performance of AlxGa1−xSb solar cells grown on GaAs substrates. The motivation is on the optimization of the growth of AlxGa1−xSb on GaAs (001) substrates to decrease the threading dislocation density resulting from the significant lattice mismatch between GaSb and GaAs. GaSb, Al0.15Ga0.85Sb, and Al0.5Ga0.5Sb cells grown on GaAs substrates demonstrate open-circuit voltages of 0.16, 0.17, and 0.35 V, respectively. In addition, a detailed study is presented to demonstrate the temperature dependence of (Al)GaSb PV cells. III-nitride semiconductors are promising candidates for high-efficiency solar cells due to their inherent properties and pre-existing infrastructures that can be used as a leverage to improve future nitride-based solar cells. However, to unleash the full potential of III-nitride alloys for PV and PV-thermal (PVT) applications, significant progress in growth, design, and device fabrication are required. In this dissertation, first, the performance of ii InGaN solar cells designed for high temperature application (such as PVT) are presented showing robust cell performance up to 600 ⁰C with no significant degradation. In the final section, extremely low-resistance GaN-based tunnel junctions with different structures are demonstrated showing highly efficient tunneling characteristics with negative differential resistance (NDR). To improve the efficiency of optoelectronic devices such as UV emitters the first AlGaN tunnel diode with Zener characteristic is presented. Finally, enabled by GaN tunnel junction, the first tunnel contacted InGaN solar cell with a high VOC value of 2.22 V is demonstrated.
Dissertation/Thesis
Doctoral Dissertation Electrical Engineering 2019

博士
國立清華大學
電機工程學系
85
In this thesis, we have demonstrated the elctrical and optical properties ofhigh-quality GaSb and AlGaSb materials grown from Sb-rich solutions by LPE.The low-temperature PL spectra is dominated by the transitions of excitonsbound to neutral acceptors and free exciton. The intensity of band A relatedto native defects can be much reduced at lower growth temperatures. The low concentration and narrow FWHM of line BE4 foe the epitaxial layers are betterthan thoso reported previously.In the thesis, we also report the accurate control of electron concentrationof GaSb epitaxial layers grown from Sb-rich solutions by LPE. The lowestelectron concentration ,5.6e15 cm-3, is obtained by using 12 wt% Te-doped poly-crystalline GaSb in the undoped GaSb starting material for the GaSb growthsolutionto suppress or compensate the background hole concentration.On the other hand, we also grow the high-quality GaInAsSb and AlGaAsSb epitaxial layersat 610 C by LPE and application to photodiodes. The fabricated AlGaAsSb/GaInAsSbPIN photodiode exhibit a dark current of 320 nA at 0.5 V, 943 nA at 3 V, respectively,and a maximum photoresponsivity of 0.58 A/W at 1.94 um corresponding to the externalquantum efficiency of 38 %. The pulse response exhibits in the photodiode witha rise time of 200 ps and a pulsewidth of 400 ps. The corresponding basedbandfrequency width at 3-dB is estimated to be 1.25 GHz which in good agreement with the calculated value of 1.47 GHz.Finally, we also demonstrated the AlGaSb/GaSb/GaInAsSb heterostructure separateabsorption and multiplication avalanche photodiode grown from Sb-rich solutions by LPE. The AlGaSb/GaSb/GaInAsSb SAM-APD exhibit a multiplicatiobn factor of 4.3at 1.5 V. The optimum of carrier concnetration and thickness of the GaSb multiplicationlayer and GaInAsSb absorption layer of the SAM-APD. Pulse response for the photodiodewas tested with a rise time of 742 ps and a pulsewidth of 345 ps. The correspondingbaseband frequency width at 3-dB reduction is broader than 1.81 GHz.

Semiconductor devices are the building blocks of electronics and communication technology in the modern world. The charge, mass and spin of charge carriers in the semiconductor devices lay the foundations of the technology developments in the modern age. But to date only the electronic charge of the semiconductors has been exploited for such applications. The significance of the spin of charge carriers is completely ignored because in a semiconductor the half of the carriers are in spin-up state and the remainder are in spin-down state. A new electronics termed as spintronics, spin-transport based electronics, is focused to utilise the spin degree of freedom of the charge carriers in addition to its electronic charge. The devices based on these have the potential for various technological advancements like non-volatility, increased data processing speed, decreased electronic power consumption and increased integration densities as compared to the conventional semiconductor devices. In this study, the author intended to study the growth and properties of magnetic impurity doped antimony based III-V compounds and compare these results with those of the films grown by MBE. This thesis is organised into seven chapters. The first introductory chapter gives a brief review of the work on spintronics, diluted magnetic semiconductors, Ferromagnetic / paramagnetic semiconductor hybrid structures with special emphasis on the properties of antimonides which have already been reported in the literature. This is followed by the scope of the thesis. The second chapter deals with technical details of various instruments used in the present research work. Third chapter describes the growth and structural properties of bulk crystals grown by Bridgman method and thin films grown by liquid phase epitaxy (LPE). Bulk crystals of InSb and GaSb doped with magnetic elements such as Mn and Fe are grown with different doping concentrations. Thin films of InSb and GaSb doped Mn with different doping concentrations are grown by LPE. The grown crystals are processed by slicing, lapping, polishing and chemical etching methods. X-ray diffraction studies are carried out to confirm alloy formation and to find the change in lattice parameter if any. From the powder diffraction patterns, the lattice parameter is refined with the help of Retvield refinement program. A systematic change of lattice parameter with the incorporation of magnetic impurities into InSb and GaSb is observed. Scanning electron microscopy and energy dispersive x-ray analysis are carried out to identify the secondary phases and their composition respectively. Chapter 4 gives the detailed magnetotransport studies carried out on InSb and GaSb crystals doped with Mn and Fe. Also, the magnetotransport studies carried out on thin films grown by liquid phase epitaxy are presented here. This chapter is divided into three sections of which the first section deals with Mn doped bulk crystals of InSb and GaSb, the second section deals with Fe doped bulk crystals of InSb and GaSb and the third section deals with Mn doped InSb and GaSb films grown on GaAs by Liquid Phase Epitaxy. Temperature dependence of zero field resistivity, magnetoresistance and Hall measurements are carried out from 1.4 to 300K. All the samples show p type conduction throughout the temperature range studied except for Fe doped InSb. Mn doped crystals show negative magnetoresistance and anomalous Hall effect below 10K. Anisotropy in magnetoresistance is also observed at low temperatures in InMnSb crystals. On the other hand, Fe doped samples exhibit positive magnetoresistance throughout the temperature range and no anomalous Hall effect is observed. Chapter 5 describes the magnetic properties of bulk InMnSb, GaMnSb, InFeSb and GaFeSb crystals so also the thin films of InMnSb/GaAs. DC magnetization measurements are carried out in the temperature range 2 - 300K. The Mn doped InSb and GaSb crystals as well as InMnSb/GaAs films, show a magnetic ordering below 10K which could arise from the InMnSb and GaMnSb alloy formation. Also, saturation in magnetization observed even at room temperature suggests the existence of ferromagnetic MnSb clusters in the crystals which has been verified by scanning electron microscopy studies. In Fe doped InSb crystals, the temperature dependent DC magnetization shows irreversibility under field cooled and zero field cooled conditions below 12K, suggesting a spin glass-like behaviour. Also, magnetization measurement shows the coexistence of ferromagnetic and paramagnetic phases throughout the temperature range studied. Existence of ferromagnetic phase could arise from secondary phases Fe1-xInx or FeSb2 present in the crystal as clusters and paramagnetic phase could arise from the randomly distributed Fe atoms in the InSb matrix. Fe doped GaSb crystals show interesting magnetic property that arises from the FeGa alloy (secondary phase) present in it. The EPR studies on Ga0.98Mn0.02Sb cluster-free (?) crystal suggest that the dominant Mn impurity in GaMnSb is Mn2+ (d5), described as ionized acceptor A−. This conclusion was derived from EPR experiments, which reveal a strong absorption line with an effective g factor very close to 2.00, the value typical for centre A−. The absence of EPR signal typical for neutral Mn acceptor A0 suggests that this center is absent in the crystal under investigation. The observed behavior is similar to that of Ga1-xMnxAs and In1-xMnxAs epilayers. EPR studies also reveal that the competition between antiferromagnetic and ferromagnetic phases exists in the studied crystal. Chapter 6 describes the optical measurements carried out on bulk Ga1-xMnxSb crystals and their films with different Mn doping concentrations. FTIR studies are carried out in the temperature range 4 - 300 K. From the FTIR studies, it is found that intra valance spin – orbit splitting band absorption is dominant compared to the fundamental absorption in doped crystals. In higher doped crystals (x > 0.01), fundamental band absorption merges with split-off band and could not be resolved. Free carrier absorption studies are also carried out in the energy range below the band gap. FTIR studies on GaMnSb/GaAs films suggest band gap narrowing effect due to Mn doping. Furthermore the Photoluminescence measurements are carried out in the temperature range 10 – 300 K for all the Mn doped GaSb crystals. PL studies also support the band gap narrowing and band filling effects. A comprehensive summary of this research investigation and scope for the further work are presented in the last chapter.