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Vertical charge transport in conjugated polymersSkrypnychuk, Vasyl January 2017 (has links)
Conjugated polymers are novel organic electronic materials highly important for organic photovoltaic applications. Charge transport is one of the key properties which defines the performance of conjugated polymers in electronic devices. This work aims to explore the charge transport anisotropy in thin films of P3HT, one of the most common conjugated polymers. Using X-ray diffraction techniques and charge transport measurements, the relation between vertical charge transport through thin P3HT films and structure of the films was established. It was shown that particular orientations of crystalline domains of P3HT, namely face-on and chain-on, are beneficial for vertical charge transport. These orientations provide the efficient pathways for the charges to be transported vertically, either via π-π stacking interaction between the adjacent conjugated chains, or via the conjugated chain backbones. It was also demonstrated that particular orientations of crystallites are favourable for the formation of interconnected percolated pathways providing enhanced vertical charge transport across the film. Deposition of P3HT on most commonly used silicon substrates typically results in the formation of mostly edge-on orientation of crystallites which is unfavourable for vertical charge transport. Nanoimprint lithography was demonstrated as a powerful processing method for reorienting the edge-on crystalline domains of P3HT into chain-on (vertical) orientation. It is also shown that thin P3HT films with preferentially face-on orientations of crystallites can be deposited on graphene surface by spin coating. Using patterning of thin P3HT films by nanoimprint lithography, unprecedentedly high average vertical mobilities in the range of 3.1-10.6 cm2 V-1 s-1 were achieved in undoped P3HT. These results demonstrate that charge transport in thin films of a relatively simple and well-known conjugated polymer P3HT can be significantly improved using optimization of crystallinity,orientation of crystallites, polymer chain orientation and alignment in the films.
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Synthèse et propriétés de ligands de type carbène N-hétérocyclique conjugués à une porphyrines / Synthesis and properties of N-heterocyclic carbene ligands conjugated with porphyrinsLefebvre, Jean-François 06 December 2010 (has links)
En plus du site de coordination interne classique des porphyrines, il est possible de fonctionnaliser le macrocycle par des sit es de coordination externes. Ce travail de thèse porte sur la fonctionnalisation de deux carbones b-pyrroliques adjacents afin d'obtenir des porphyrines conjuguées avec des ligands de type carbène N-hétérocyclique (CNH).Les CNHs présentent de remarquables propriétés électroniques qui en font aujourd'hui des ligands incontournables en catalyse et en chimie organométallique. L'objectif de ce travail de thèse a été d'étudier l'influence de la porphyrine sur les propriétés électroniques du ligand périphérique CNH, et de moduler les propriétés électroniques et catalytiques de complexe métalliques en fonction des modifications chimiques apportées à la porphyrine, à savoir sa métallation ou la protonation des azotes de la porphyrine base-libre.Dans un premier temps, les différentes méthodes de synthèse développées afin d'obtenir différents sels d'imidazolium conjugués avec le macrocycle porphyrinique sont développées. Ces sels d'imidazolium sont les précurseurs des ligands porphyrine-CNH. Afin d'étudier les propriétés catalytiques de complexes contenant des ligands de type porphyrine-CNH, plusieurs complexes de palladium(II) ont été synthétisés et caractérisés. Les études des propriétés catalytiques de ces complexes testées sur le couplage de Heck ont démontré que de bien meilleures activités catalytiques étaient observées si les porphyrines contiennent un cation métallique. Enfin, les propriétés des ligands CNH ont été étudiées sur des complexes de types (CNH)Rh(COD)X et (CNH)Rh(CO)2X avec X = I ou Cl. / In addition to the usual inner coordination site of porphyrins, it is possible to functionalize the macrocycle by external coordination sites. This PhD thesis is devoted to the functionalization of two neighboring b-pyrrolic carbons in order to obtain porphyrins fused to peripheral N-heterocyclic carbene ligands (NHC).NHC ligands are known to display outstanding electronic properties which render them important ligands in the fields of catalysis and organometallic chemistry. The aim of this PhD work was to study the influence of the porphyrin on the electronic properties of the peripheral NHC ligand, and to modulate the electronic and catalytic properties of anchored metal complexes according to the chemical modifications brought to the porphyrin, ie. its metallation or the protonation of the free-base porphyrin.Firstly, the different synthetic procedures to obtain porphyrins fused to imidazolium rings were developed. These imidazolium salts are the key precursors of the porphyrin-NHC ligands. In order to study the catalytic properties of metal complexes containing porphyrin-NHC ligands, several palladium(II) complexes were synthesized and characterized. The study of the catalystic properties of these complexes showed that better catalytic activities were observed if the porphyrins contain a metal cation. Then, the electronic properties of these NHC ligands were evaluated for (NHC)Rh(COD)X and (NHC)Rh(CO)2X complexes with X = I or Cl.
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Synthèse et étude de nouvelles molécules potentiellement polymérisables pour la fabrication de matériaux électroluminescents : analogues du 1,3,5 benzènetripyrrole, méthyle 3,5-bipyrrolebenzoate et 6,12-diméthyle-1,5-dipyrrolediazocaneMbyas Saroukou, Mariame Scarlett 12 1900 (has links)
Pyrroles are found in various natural products and in the chemical composition of certain drugs because of their interesting biological properties. Lipitor, Tolmetin and Amtolmetin are examples of drugs with 1,2,5-substituted pyrroles in their composition, in which biological activities have been certified. Moreover, pyrroles are used as precursors of semiconductor polymers, oligomers and dendrimers useful for the synthesis of electroluminescent materials used in devices, such as organic light-emitting diodes, field-effect transistors, solar and organic photovoltaic cells. We are interested in conjugated polymers based on pyrrole due to their optical properties, electrochemical and the conductivity produced by electron delocalization along their carbon chains.
The overall objective of the work presented in this thesis is the synthesis of new molecules based on pyrrole for studying their electronic and electrochemical properties as well for the synthesis of conjugated polymers.
Initially, we performed the synthesis of 1,3,5-tri-(1-alkyl-5-methylpyrrol-2-yl)benzenes, which may serve as precursors for the synthesis of conjugated dendrimers. Their synthesis was made in three steps starting from trimethyl 1,3,5-benzene-tricarboxylate which was converted to 1,3,5-tri-(pent-4-enoyl)benzene using vinylmagnesium bromide in a Grignard reaction catalyzed by copper cyanide. The olefins of 1,3,5-tri-(pent-4-enoyl)benzene were oxidized to produce 1,3,5-tri-(4-oxopentanoyl)benzene using a modified protocol of the Tsuji-Wacker reaction. Subsequent, Paal-Knorr condensation reactions on 1,3,5-tri-(4-oxopentanoyl)benzene with different amines were used to synthesize 1,3,5-tri-(1-alkyl-5-methylpyrrol-2-yl)benzenes with different N-substituents in yields between 44 and 60%. Incomplete reaction of vinylmagnesium bromide with trimethyl 1,3,5-benzenetricarboxylate gave the methyl-3,5-di(pent-4-enoyl)benzoate, which was converted to methyl-3,5-dipyrrolylbenzoate following the reaction of Tsuji- Wacker and Paal-Knorr with yields between 30 and 60%.
The photochemical and electrochemical properties of the 1,3,5-tri-(1-alkyl-5-methylpyrrol-2-yl)benzenes and methyl-3,5-dipyrrolylbenzoates were studied in collaboration with the research group of professor William Skene. The results have shown that both types of pyrrole have potential for the synthesis of conjugated polymers and dendrimers used in the manufacture of electroluminescent materials. Following these encouraging results, we performed the synthesis of 6,12-dimethyl-1,5-dipyrrolediazocane. Methyl N-(Boc)-β-alaninate was converted to its corresponding homoallylic ketone, which was oxidized to N-(Boc)aminoheptan-3,6-dione. The Paal-Knorr condensation between N-(Boc)aminoheptan-3,6-dione and aminoheptan-3,6-dione hydrochloride gave 6,12-dimethyl-1,5-dipyrrolediazocane in 17% yield.
In sum, we have synthesized and characterized seven new molecules, six of them having photochemical and electrochemical properties interesting for the synthesis of conjugated polymers and dendrimers. The latter offering potential as precursor for the conception of compounds of therapeutic interest. / Les pyrroles sont une classe de molécules que l'on trouve dans divers produits naturels ainsi que dans la composition chimique de certains médicaments en raison de leurs propriétés biologiques intéressantes. Le Lipitor, la Tolmetin et l'Amtolmetin sont des exemples de médicaments à base de pyrroles 1,2,5 substitués dont les activités biologiques ont été certifiées. Les pyrroles sont aussi utilisés comme précurseurs de polymères, oligomères et dendrimères semi-conducteurs nécessaires à la synthèse de certains matériaux électroluminescents, tels que les diodes organiques électroluminescentes, les transistors à effets de champ et les cellules organiques photovoltaïques. Nous nous sommes intéressés à ces polymères conjugués à base de pyrroles en raison de leurs qualités de bons conducteurs, de leurs propriétés optiques et électrochimiques que leur confère la délocalisation des électrons le long de leurs chaines carbonées.
L'objectif général des travaux présentés dans ce mémoire est de synthétiser de nouvelles molécules à base de pyrroles pouvant éventuellement servir de précurseurs à la synthèse de dendrimères conjugués ainsi qu'à la synthèse de molécules thérapeutiques. Une étude de leurs propriétés électroniques et électrochimiques sera effectuée afin de déterminer leur potentiel pour la fabrication de matériaux électroluminescents.
Dans un premier temps, la synthèse des analogues du 1,3,5-benzènetripyrrole a été faite en trois étapes à partir du 1,3,5-benzènetricarboxylate de triméthyle. Celui-ci a été converti en premier lieu en 1,3,5-benzènetricétone-γ,δ-insaturée lors d'une réaction de Grignard catalysée par le cyanure de cuivre. Ce dernier composé fut oxydé lors de la seconde étape en 1,3,5-tri-(4-oxopentanoyl)benzène selon un protocole modifié de la réaction de Tsuji-Wacker. Enfin, la réaction de condensation de Paal-Knorr du 1,3,5-tri-(4-oxopentanoyl)benzène de l'étape précédente mène au 1,3,5-benzènetripyrrole N-substitué selon l'amine utilisée pour la condensation, avec des rendements entre 44 et 60%.
La réaction incomplète du bromure de vinylmagnésium avec le 1,3,5-benzènetricarboxylate de triméthyle mène au méthyl-3,5-di-(pent-4-énoyl)benzoate, qui a été converti en méthyl-3,5-dipyrrolylbenzoate suite à la réaction de Tsuji-Wacker et de Paal-Knorr avec des rendements entre 30 et 60%.
L'étude des propriétés photochimiques et électrochimiques des tripyrroles et des bipyrroles a été faite en collaboration avec le groupe de recherche du professeur William Skene. Les résultats obtenus démontrèrent que ces pyrroles auraient un potentiel pour la synthèse de dendrimères conjugués servant à la fabrication de matériaux électroluminescents. Suite à ces résultats encourageants, la synthèse du 6,12-diméthyle-1,5-dipyrrolediazocane a aussi été réalisée. Celui-ci a été synthétisé à partir de l’ester méthylique de l’acide 3-tert-butoxycarbonylaminopropionique qui a été converti en sa cétone homoallylique correspondante, puis oxydée en N-Boc-3,6-dioxoheptylcarbamate. La condensation de Paal-Knorr de ce dernier composé avec le sel d'hydrochlorure 7-aminoheptane-2,5-dione mène au 6,12-diméthyle-1,5-dipyrrolediazocane avec un rendement de 17%. En somme, la recherche effectuée a permis la synthèse et la caractérisation de six nouvelles molécules ayant des propriétés photochimiques et électrochimiques intéressantes pour la synthèse de polymères et dendrimères conjugués. Ainsi que la synthèse d'un diazacycle, qui de part sa structure pourrait servir de précurseur à la synthèse de molécules thérapeutiques.
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Vacuum deposition of organic molecules for photovoltaic applicationsKovacik, Peter January 2012 (has links)
Organic photovoltaics have attracted considerable research and commercial interest due to their lightness, mechanical flexibility and low production costs. There are two main approaches for the fabrication of organic solar cells – solution and vacuum processing. The former relies on morphology control in polymer-fullerene blends resulting from natural phase separation in these systems. The latter takes advantage of solvent-free processing allowing highly complex multi-junction architectures similar to inorganic solar cells. This work aims to combine the benefits of both by depositing conjugated polymers using vacuum thermal evaporation. By employing this unconventional approach it aims to enhance the efficiency of organic photovoltaics through increased complexity of the thin-film architecture while improving the nanoscale morphology control of the individual active layers. The thesis explores the vacuum thermal deposition of polythiophenes, mainly poly(3-hexylthiophene) (P3HT) and side-group free poly(thiophene) (PTh). A variety of chemical techniques, such as NMR, FT-IR, GPC, DSC and TGA, are used to examine the effect of heating on chemical structure of the polymers. Optimal processing parameters are identified and related to the resulting thin-film morphology and charge transport properties. Efficient photovoltaic devices based on polythiophene donors and fullerene acceptors are fabricated. Materials science techniques AFM, XRD, SEM, TEM and MicroXAM are used to characterize topography and morphology of the thin films, and UV-Vis, EQE, I-V and C-V measurements relate these to the optical and electronic properties. The results of the study show that polymer side groups have a strong influence on molecular packing and charge extraction in vacuum-deposited polymer thin films. Unlike P3HT, evaporated PTh forms highly crystalline films. This leads to enhanced charge transport properties with hole mobility two orders of magnitude higher than that in P3HT. The effect of molecular order is demonstrated on polymer/fullerene planar heterojunction solar cells. PTh-based devices have significantly better current and recombination characteristics, resulting in improved overall power conversion efficiency (PCE) by 70% as compared to P3HT. This confirms that the chemical structure of the molecule is a crucial parameter in deposition of large organic semiconductors. It is also the first-ever example of vacuum-deposited polymer photovoltaic cell. Next, vacuum co-deposited PTh:C60 bulk heterojunctions with different donor-acceptor compositions are fabricated, and the effect of post-production thermal annealing on their photovoltaic performance and morphology is studied. Co-deposition of blended mixtures leads to 60% higher photocurrents than in thickness-optimized PTh/C60 planar heterojunction counterparts. Furthermore, by annealing the devices post-situ the PCE is improved by as much as 80%, achieving performance comparable to previously reported polythiophene and oligothiophene equivalents processed in solution and vacuum, respectively. The enhanced photo-response is a result of favourable morphological development of PTh upon annealing. In contrast to standard vacuum-processed molecular blends, annealing-induced phase separation in PTh:C60 does not lead to the formation of coarse morphology but rather to an incremental improvement of the already established interpenetrated nanoscale network. The morphological response of the evaporated PTh within the blend is further verified to positively differ from that of its small-molecule counterpart sexithiophene. This illustrates the morphological advantage of polymer-fullerene combination over all other vacuum-processable material systems. In conclusion, this processing approach outlines the conceptual path towards the most beneficial combination of solution/polymer- and vacuum-based photovoltaics. It opens up a fabrication method with considerable potential to enhance the efficiency of large-scale organic solar cells production.
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Différentes stratégies d’auto-assemblage de dérivés diacétyléniques porteurs d’hétérocycles azotés aromatiques : application à la synthèse de matériaux / Various strategies for the self-assembly of diacetylene derivatives bearing nitrogen- containing aromatic heterocycles : application to the synthesis of materialsFahsi, Karim 06 December 2012 (has links)
Les polydiacétylènes sont des polymères π-conjugués, obtenus par polymérisation topochimique à l'état solide de motifs diacétyléniques, sous l'effet d'un stimulus thermique ou photochimique. Depuis leur découverte en 1969 par Wegner, les polydiacétylènes ont fait l'objet de nombreux travaux de recherche. Ces travaux ont consisté tout d'abord à élucider le mécanisme de polymérisation, puis à étudier les diverses propriétés photophysiques, optiques, et électroniques des polymères. Néanmoins, la plupart des diacétylènes étudiés ne possédaient pas de substituants susceptibles d'être modifiés chimiquement. Le premier chapitre de cette thèse décrit la synthèse de nouvelles molécules diacétyléniques symétriques comportant des groupements azoles, et l'étude de leur polymérisation à l'état solide. La modification de l'organisation des motifs diacétyléniques.par interaction avec des molécules capables de former des liaisons hydrogène, et l'incorporation de ces motifs dans des matériaux hybrides organiques-inorganiques de type,. MOF ont également été examinées.Dans le deuxième chapitre, nous nous sommes intéressés aux composés diacétyléniques dicationiques fonctionnalisés par des groupements triéthylammoniums, imidazoliums et benzimidazoliums. La synthèse de ces composés, leur caractérisation spectroscopique, et cristallographique, ainsi que l'étude de leur réactivité thermique et photochimique ont été réalisées.Dans le troisième chapitre, nous proposons une méthode directe de préparation de carbone dopé à l'azote par pyrolyse des molécules diacétyléniques neutres, ainsi que la synthèse de carbone mésoporeux en présence d'un sel métallique. Un autre aspect de ce chapitre est l'optimisation des teneurs en azote en utilisant comme précurseurs les composés diacétyléniques dicationiques, associés à des anions riches en azote, notamment l'anion dicyanamide [dca] et tricyanométhide [tcm]. / Diacetylenes (DA) are unusual molecules owing to their ability to polymerize in the solid state. Such a polymerization is triggered off thermally or photochemicaly, and leads to the formation of enyne structures. Since their discovery in 1969 by Wegner, polydiacetylenes (PDA) have been the focus of much attention. Initially, many studies were devoted to elucidating the mechanism of polymerization, then assessment of the diverse photophysical, optical, and electronic properties of the polymers became the main goal. Yet, the vast majority of the DA that were studied did not possess substituents that could be modified chemicallyThe first chapter describes the synthesis of new symmetrical diacetylenic molecules functionalized with azole substituents and the study of the polymerization of these compounds in the solid state. Then, we present the modification of the organization of these diacetylenes by the interaction with molecules capable of forming hydrogen bonds, and the use of these molecules as ligands for the synthesis of Metal Organic Frameworks (MOF).The second chapter is devoted to the synthesis, characterization and crystallographic study of ionic diacetylenic compounds bearing triethylammonium, imidazolium and benzimidazolium groups. The photochemical and thermal behaviors of these DA have been tested.In the third chapter, we propose a straightforward route to N-doped graphitic carbon by direct pyrolysis of neutral diacetylenic precursors, and investigate the possibility of forming porous materials by adding a metal salt as a catalyst. Furthermore, another aspect of this chapter was to optimize the nitrogen content of these materials by using dicationic DA with N-rich anions, e.g. dicyanamide [dca] and tricyanomethide [tcm].
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Vrozené poruchy metabolismu bilirubinu / Inherited Disorders of Bilirubin MetabolismŠlachtová, Lenka January 2013 (has links)
Inherited disorders of bilirubin metabolism - hereditary hyperbilirubinemias - are metabolic disorders manifested in early childhood. Unconjugated hyperbilirubinemias result from the defect of the enzyme uridine diphosphoglucuronosyltransferase (UGT1A1). UGT1A1 mediates the conjugation of bilirubin with glucuronid acid in hepatocytes and its elimination to water soluble compound. In the next step of bilirubin degradation the transport of conjugated bilirubin from hepatocyte into the bile occure. It is caused by the ATP dependent transporters ABCC2, ATP1B1 and OATP1B3. Mutations in the genes coding the bilirubin transporters results in conjugated hyperbilirubinemia Dubin-Johnson or Rotor syndrome. This study is focused on unconjugated hyperbilirubinemia in adolescents including the non-typical manifestations and the defects of ABCC2 transporter and their phenotype in humans.
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Studie molekulárně hmotnostní a konfigurační stability substituovaných polyacetylenů / Study of molecular weight and configurational stability of substituted polyacetylenesTrhlíková, Olga January 2013 (has links)
3 ABSTRACT Complexes [Rh(cycloolefin)(acac)] (cycloolefin = norborna-2,5-diene, cycloocta- 1,5-diene and cyclooctatetraene) were investigated as catalysts of polymerization of monosubstituted acetylenes into stereoregular cis-transoid polyacetylenes. All complexes were highly active in arylacetylenes polymerizations in both coordinating and non-coordinating solvents. Selection of solvent and cycloolefin ligand of the catalyst allowed the control over polymer MW. The onset of initiation in the [Rh(cycloolefin)(acac)]/monomer systems proceeded as the proton transfer from the monomer molecule to the acac ligand under the release of acetylacetone and coordination of -C≡CR ligand to Rh(cycloolefin) moiety. Cis-transoid poly(phenylacetylene) and poly[(2,4-difluorophenyl)acetylene]s with required initial MW were prepared with these catalysts and submitted to the long-term ageing in which the polymers were exposed to the atmosphere and diffuse daylight either dissolved in tetrahydrofuran or in the solid state. Tightly connected processes of cis-to-trans isomerization of the polymer main-chains double bonds and oxidative degradation were found to proceed during polymers ageing in the solution. Besides, the formation of corresponding cyclotrimers accompanied the polymers ageing. However, the cyclotrimers amount was...
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Estudo atomístico da desordem eletrônica em filmes amorfos de polímeros conjugados / Atomistic Study of Electronic Disorder on Amorphous Films of Conjugated PolymersSilva, Rodrigo Ramos da 10 October 2014 (has links)
O emprego de polímeros conjugados e blendas como camada ativa de diodos emissores de luz ou células fotovoltaicas é foco de intenso desenvolvimento científico na atualidade. O desempenho eletro-ótico de tais dispositivos é fortemente dependente das características estruturais e eletrônicas dos componentes poliméricos ou moleculares, que são difíceis de serem quantificadas, demandando a integração de resultados experimentais e modelagem teórica. A desordem intrínseca desses materiais também dificulta a modelagem e a simulação, sendo necessário o emprego de diferentes e complementares métodos e técnicas de física computacional. O presente trabalho tem como objetivo o estudo, em nível atomístico, da correlação entre propriedades morfológicas e eletrônicas de filmes poliméricos com alta desordem de: I) poli-para-fenileno-vinileno (PPV); II) poli-3-hexil-tiofeno (P3HT) e sua blenda com fulereno (C60). Empregamos modelagem por Dinâmica Molecular Clássica dos sistemas desordenados em temperatura finita; implementamos para tal adaptações específicas no Campo de Forças Universal, baseadas em cálculos quânticos de primeiros princípios. Para obtermos a estrutura eletrônica de modelos selecionados utilizamos método de Hartree-Fock semiempírico. O sistema de PPV é estudado com respeito à variação das propriedades morfológicas ao longo do processo de deformação uniaxial. Estabelecemos correspondência entre os efeitos do estiramento e o surgimento de anisotropia no espectro de fotoluminescência observado experimentalmente. Para os sistemas de P3HT simulamos diferentes tipos de empacotamento, estudamos as propriedades morfológicas e calculamos os estados eletrônicos relevantes ao transporte de buracos pelo polímero. Vemos como majoritária a ocorrência de estados com comprimento conjugado de quatro e cinco meros; além disso, com a desordem estrutural os níveis eletrônicos localizados passam a exibir grande proximidade em energia, com pouca relação ao comprimento de conjugação. Isso resulta no surgimento de uma Densidade de Estados gaussiana com largura de aproximadamente 100meV que se mostra independente das diferenças morfológicas entre os modelos simulados. / The use of organic conjugated polymers and blends as active layers of light emitting diodes and photovoltaic cells has been the focus of intense scientific development in recent years. The electro-optical performance of such devices depends strongly on the structural and electronic properties of the polymeric or molecular components, and is of difficult characterization, demanding integration of experimental results and theoretical modeling. A complicating factor to the theoretical modeling is the intrinsic disorder in these materials, which demands the use of different and complementary techniques and methods of computational physics. The goal of the present work is to study at the atomistic level the correlation between morphological and electronic properties of highly disordered films of: I) poly-para-phenylene-vinylene (PPV); II) poly-3-hexyl-thiophene (P3HT) and blends with fullerenes (C60). We applied Classical Molecular Dynamics to model the disordered systems at finite temperature employing the well-known Universal Force Field, to which we implemented specific corrections based on first-principles quantum calculations. For selected models we calculated the electronic structure through semiempirical Hartree-Fock. The PPV system was studied focusing on the effect of uniaxial stretching on morphological properties. We have established a connection between morphology effects and the anisotropy of light emission detected experimentally. For P3HT systems we simulated different packing systems and studied morphological properties, and the electronic structure of the localized states relevant to hole transport in the polymer film. We found higher occurrence of 4- and 5-mer long conjugated electronic states. Moreover, the structural disorder affects the electronic levels, reducing the energy separation of conjugated segments of different lengths. This makes possible the occurrence of a gaussian Density of States of approximately 100meV width, regardless of the different morphological signatures of the different simulated models.
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Efeitos do ácido linoléico conjugado sobre parâmetros do metabolismo lipídico alterados pela caquexia. / Effects of conjugated linoleic acid upon lipid metabolism in cachexia.Gonçalves, Daniela Caetano 06 July 2010 (has links)
Este trabalho investigou os efeitos do CLA sobre o metabolismo lipídico na caquexia. Grupos controle ou tumor foram suplementados com CLA, óleo de girassol ou salina, por gavagem, por 14 dias. O peso corporal, ração, glicose, colesterol, TAG, insulina e leptina plasmáticos, glicogênio, proteína, TAG, expressão gênica da CPT I and II, MTP, L-FABP, PPAR-α e apoB, o conteúdo proteíco da apoB e a atividade máxima da CPT I e II no fígado, o conteúdo de gordura no TAE e TARP e a concentração proteíca e de IL-1β,IL-6,TNF-α e IL-10 desses tecidos foram determinados. A atividade da CPT II mostrou-se reduzida em todos os grupos em relação a C. o mRNA da MTP, apoB e FABP foi inferior em todos os grupos TB, mas no TBCLA esta redução foi maior. Todos os grupos mostraram expressão diminuída de proteína apoB em relação a C. TBCLA aumentou o TAG hepático e plasmático, assim como colesterol e glicose quando comparado com os grupos TB. O TAG no TAE diminuiu em TBCLA em relação a C, TBSF e CCLA. Houve diminuição de IL-1β no CCLA em relação a C, mas em TBCLA a IL-1β foi superior em relação a C, TB e TBSF. TBCLA mostrou um aumento de IL-6 em relação a TB e CCLA. O TBCLA mostrou aumento de TNF-α quando comparado com TB e CCLA. O CLA falhou em promover a recuperação do metabolismo lipídico em animais caquéticos. / We investigated the effects of CLA upon lipid metabolism in cachexia. Male Wistar rats were assigned to a control or cachetic rats, supplemented with CLA, sunflower oil or saline, for 14 days. Body weight, dietary intake, plasma glucose, cholesterol, insulin and leptin, and liver TAG, glycogen and protein, CPT I and II, MTP, L-FABP, PPAR-α, apoB gene expression, apoB protein content and the maximal activity of CPT I and II, were assessed. The fat content of EAT and RPAT, and adipose tissue IL-1β,IL-6,TNF-α and IL-10 content were assessed. CPT II activity was reduced in all groups when compared with C. mRNA expression of MTP, apoB and FABP were reduced in all TB groups, but TBCLA showed the greatest reduction of apoB and MTP mRNA and apoB protein content. TBCLA increased liver and plasma TAG, cholesterol and glucose content, when compared with TB groups. TAG in EAT decreased in TBCLA group when compared with C, with TBSF, and with CCLA. Decreased IL-1β in CCLA was found in relation to C, TBCLA enhanced IL-1β in relation to C, TB and TBSF. TBCLA, increased IL-6 when compared with TB and CCLA. TBCLA showed higher TNF-α in relation to TB and CCLA. We conclude that CLA fails promoting the re-establishment of lipid metabolism in cachexia.
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Fotofísica em heteroestruturas contendo o polímero emissor PPV e espécies supressoras / Photophysics in nanostructured films containing poly(p-phenylene vinylene) (PPV) and acceptor species.Postacchini, Bruna Bueno 12 January 2009 (has links)
A compreensão dos caminhos de desativação não radiativa em polímeros conjugados é fundamental para o uso desses materiais em dispositivos luminescentes, células fotovoltaicas e sensores. Nesta tese, os processos não radiativos em filmes automontados de polímero luminescente foram investigados via análise da supressão de intensidade de fotoluminescência, utilizando a técnica de fluorescência estacionária, e através da medida do tempo de vida do estado excitado com fluorescência resolvida no tempo em arranjo de contagem de fótons. A camada emissiva constituída por poli(p-fenileno vinileno) (PPV) obtido da conversão térmica do precursor poli(cloreto de xilideno tetraidrotiofeno) (PTHT) apresentou tempos de vida entre 150 e 250 ps, e fraca dependência com o comprimento de onda de detecção da emissão. Na presença de uma monocamada contendo azocorante Vermelho do Congo (CR) ou ftalocianina tetrassulfonada de níquel (NiTsPc) atuando como receptor de energia foi observada supressão da fluorescência e encurtamento do tempo de vida (50-100ps). À medida que se aumenta a distância entre as camadas de doador e receptor via interposição de bicamadas de espaçador, a dinâmica do sistema tende à dinâmica de decaimento do estado excitado do PPV na ausência de receptor. A dependência da eficiência com a distância 1/r2 ou 1/r3 apontam para transferência de energia ressonante (RET) típica da interação plano-plano ou plano-camada. Os processos não radiativos foram também estudados em função da diluição de segmentos PPV dispersos em matriz de polieletrólito poli(cloreto de dodecildimetilamônio) PDAC. A diluição dos segmentos conjugados aumenta a eficiência quântica de emissão, torna o mecanismo de desativação mais lento (500 ps) e diminui a dependência do tempo de vida com o comprimento de onda de detecção, devido à menor eficiência dos mecanismos de desativação não radiativa. Na presença de uma camada receptora, a eficiência de transferência de energia é maior para amostras com segmentos mais diluídos indicando que esse mecanismo compete com os processos internos à própria camada emissiva. O tempo de vida aumenta em filmes com mais baixo grau de conjugação e a dependência com o comprimento de onda de emissão é mais forte. Em resumo, a técnica de automontagem se mostrou adequada para obter filmes com propriedades fotofísicas controláveis no nível molecular, que puderam ser estudadas com espectroscopias de fluorescência. / Understanding the pathway of excitation in conjugated polymers is important for using these materials as active layer in devices, photovoltaic cells and sensors. In this thesis, non-radiative processes in layer-by-layer (LbL) films were investigated with measurements of fluorescence quenching in steady-state fluorescence spectroscopy and of the singlet excited state lifetime using time-resolved fluorescence spectroscopy in a single photon counting (SPC) apparatus. The emissive layer of poly(p-phenylene vinylene) (PPV) obtained via thermal conversion of the soluble precursor poly(xylylidene tetrahydrothiophenium) chloride (PTHT) showed lifetime 150-250 ps and weak dependence on the emission wavelength. In the presence of an acceptor layer of either Congo Red (CR) or nickel tetrasulfonated phthalocyanine (NiTsPc) the PL intensity was quenched and the lifetime was shorter (50 -100 ps). Upon increasing the distance between the energy donor (PPV) and acceptor layers by interposing bilayers of inert polyelectrolytes the dynamics tended to the PPV dynamics. The distance-dependence of the energy transfer efficiency (1/r2 or 1/r3) points to a resonant process (RET) with a plane-to-plane or plane-to-slab interaction. The non-radiative processes were also studied for varying dilutions of the PPV segments in a matrix of the polyelectrolyte poly(dodecyl methylamonium chloride) (PDAC). This dilution increased the quantum efficiency and led to longer lifetimes (500 ps) owing to a less effective non-radiative energy transfer. When an energy acceptor layer is present, energy transfer is more efficient for the most diluted systems, indicating that such transfer competes with internal processes in the emissive layer. The lifetime increased in films with low degree of conjugation, for which there was a stronger dependence on the emission wavelength. It is concluded that the LbL methodology was suitable to obtain photophysical film properties that could be controlled at the molecular level, and investigated with varied fluorescence spectroscopies.
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