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Elaboration de molécules pi-conjuguées à base de triphénylamine pour la réalisation de dispositifs photovoltaïques hybrides sensibilisés.Metri, Noura 30 September 2011 (has links)
Les cellules photovoltaïques hybrides sensibilisées « tout solide » (ssDSSC) sont considéréescomme une technologie émergente dans le domaine de l'énergie solaire afin de remplacer les cellules solaires classiques basées sur le silicium ou même celles utilisant un électrolyte liquide(DSSC). Dans ce but, nous nous sommes intéressés à l'élaboration de molécules p-conjuguées (verresmoléculaires) de type « p » pour une application dans les ssDSSCs.Le premier axe de cette étude a consisté à synthétiser deux familles de molécules à base detriphénylamine/thiéno[3,2-b]thiophène/ thiophène (avec et sans chaîne nonyle pour déterminerl'effet de la solubilité). Ces composés ont été obtenus par des couplages de Stille ou Suzuki avec des rendements globaux variant entre 11% et 37% (pour six à dix étapes).Dans le but de déterminer les propriétés physico-chimiques des composés obtenus, lesecond axe a été consacré aux caractérisations thermiques, optiques et électroniques des moléculessynthétisées. Les mesures thermiques par analyse thermogravimétrique (ATG) ont montré unestabilité des composés supérieure à 340°C. En outre, l'analyse thermique différentielle (DSC) apermis de déterminer la température de transition vitreuse (Tg), la plus élevée atteignant 57°C. Lesgaps optique et électronique ont été déterminés par absorption UV-Visible (entre 2,87eV à 2,41eV enfilm) ou voltampérométrie cyclique (entre 3,26eV à 2,60eV). Les niveaux énergétiques de la HOMO etLUMO ont également été déterminés par voltampérométrie cyclique. Ils ont montré des niveauxadéquats surtout pour celui de la HOMO (compris entre la HOMO du colorant et celle de la cathode)pour une application photovoltaïque. Enfin, les mesures de mobilité de trous ont mis en évidence desrésultats encourageants et prometteurs variant entre 10-3 cm2.V-1.s-1 et 1 cm2.V-1.s-1.Le troisième axe est consacré à l'étude théorique de ces molécules à l'aide de la modélisationmoléculaire. Les tendances obtenues pour les niveaux énergétiques (HOMO et LUMO), les gaps optiques, l'énergie de réorganisation interne (donnant une idée de la mobilité théorique de charges)recoupent assez bien les données expérimentales.Finalement, le dernier axe porte sur la détermination des performances photovoltaïques de ces composés. Pour l'un d'eux une efficacité de 0,5% a été obtenue sans optimisation et de manièredurable puisque cette efficacité reste inchangée après une année. Le taux de remplissage de cecomposé dans TiO2 atteint de 62 à 83%.Mots clés : Dispositifs photovoltaïques hybrides « tout solide » ssDSSC, triphénylamine, thiéno[3,2-b]thiophène, thiophène, verre moléculaire, modélisation moléculaire, taux de remplissage. / Solid state dye-sensitized solar cells (ssDSSC) are considered as an emerging technology in order to replace conventional silicon solar cells or even those using liquid electrolyte. In order to improve the performance of ssDSSC devices, we were interested by the development of star-shaped molecules derived from thieno[3,2-b]thiophene unit and triphenylamine core.Two series of new substituted triphenylamine (TPA) derivatives with thiophene and thieno[3,2-b]thiophene units (with and without nonyl group C9H19) were synthesized in a combinatorial manner. These compounds were obtained by Stille or Suzuki coupling with a yield between 11% and 37% (from six to ten steps).In order to determine the properties of these compounds, thermal, optical and electrochemical characterizations were carried out. The measurements by thermogravimetric analysis (TGA) showed a high stability of the compounds above 340°C. Differential thermal analysis (DSC) was used to determine the glass transition temperature (Tg) where the highest reaching 57°C. The optical and electronic gaps were determined by UV-Visible absorption ( we found from 2.87 eV to 2.41 eV in film) or cyclic voltammetry (we found from 3.26 eV to 2.60 eV). The energy levels of HOMO and LUMO were also determined by cyclic voltammetry. They showed adequate levels especially for HOMO levels (ideally HOMO between the dye and that of the cathode) for a photovoltaic application. Finally, hole mobility have shown encouraging results and promising ranging from 10-3 cm2.V-1.s-1 and 1 cm2.V-1.s-1.The theoretical study of these molecules was also carried out using molecular modeling as B3LYP. The energy levels (HOMO and LUMO), the optical gaps, and the energy of internal reorganization (giving an idea of the theoretical charges mobility) have the seam trend overlap the experimental data.The photovoltaic performance of these compounds was performed. An efficiency of 0.5% (not optimized results) has been obtained for the best of them. This efficiency was sustainable after one year. The pore filling ratio of this compound in TiO2 reached from 62 to 83%.Keywords : Solid state dye-sensitized solar cells (ssDSSC), triphenylamine, thieno[3,2-b]thiophene, thiophene, molecular glasses, theoretical calculations, pore filling.
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Synthesis of Thiophene-Vinyl-Benzothiazole Based Ligand Analogues for Detection of Aβ and Tau Pathology in Alzheimer's DiseaseJohansson, Joel January 2024 (has links)
As of today, Alzheimer’s disease is the leading cause of dementia among neurodegenerative disorders, affecting many millions of people worldwide. As the average life span of populations increase, more and more people succumb to the illness each year. Like other neurodegenerative disorders, Alzheimer’s disease can be attributed to the accumulation of protein aggregates in the brain. These amyloid-β peptides and tau proteins can presumably be detected in the brain many years before the onset of clinical symptoms. Development of fluorescent ligands, capable of binding to these neuropathological hallmarks and highlighting them, could serve as molecular diagnostic tools and facilitate an early diagnosis of the disease. The method could also be useful in studying disease progression and evaluating the effects of novel treatments. One such ligand is HS-259. The aim of this project was to synthetize different analogues of HS-259, and test their selectivity towards the aforementioned aggregates in brain tissue from an individual with Alzheimer’s disease. Staining of tissue samples with analogue solution enables visualization of aggregate sites through fluorescence imaging. In the end, five analogues were synthetized, albeit in relatively low overall yields. Synthetic methods included Suzuki-Miyara cross-couplings, Ullmann-type arylations and condensations. Liquid Chromatography-Mass Spectrometry (LC-MS) and Nuclear Magnetic Resonance (NMR) were used for analysis of the compounds. Two of the five analogues could be tested for staining of aggregates and assessed for photophysical characteristics, i.e. absorption- and emission spectra. One analogue stained both amyloid-β aggregates and some tau aggregates, whereas the other stained neither. Since only two analogues were tested and rendered inconsistent results, further studies are needed to assess the binding properties of HS-259 analogues in general.
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Etude de l'adsorption de composés organiques sur des matériaux poreux de type Metal Organic Framework (MOF)Boulhout, Mohammed 12 December 2012 (has links)
Afin de répondre aux demandes des industriels de nouveaux matériaux poreux sont testés pour de nouvelles applications ou pour améliorer les procédés existants. Les adsorbants de types Metal Organic Frameworks(MOFs) ont des structures construites à partir d'unités inorganiques reliées entre elles par des ligands organiques. La possibilité de varier ces deux entités, offre une grande diversité de structures avec des cavités de tailles contrôlées. L'objectif de cette thèse a été d'évaluer les performances des MOFs pour l'adsorption de composés organiques et de comprendre les mécanismes d'adsorption. Les deux problématiques sélectionnées sont d'intérêt pour l'industrie pétrochimique. La séparation du para-xylène des autres isomères du xylène et de l'éthylbenzene, permets de répondre à la demande de matière première pour la synthèse du polytéréphtalate d'éthylène. L'adsorption des composés azotés et soufrés (teneur fixée par des législations), permets la purification de carburants. Notre étude thermodynamique est basée sur la réalisation d'isothermes d'adsorption et la détermination d'enthalpies d'adsorption par microcalorimétrie en phase liquide. L'adsorption des vapeurs des xylènes purs a été étudiée pour comprendre l'effet du solvant. Une grande variété de comportement a été observée selon les structures des MOFs. Nous avons par exemple mis en évidence l'effet de l'empilement moléculaire des isomères du xylène sur la sélectivité des MOFs. Nous avons démontré que la flexibilité des MOFs intervient sur les interactions au cours de l'adsorption des xylènes. Nous avons mis en évidence une sélectivité des MOFs possédant un centre métallique insaturé en faveur des composés azotés / In order to meet the industrials requirements, new porous materials are tested for new applications or to improve existing processes. The Metal Organic Frameworks (MOFs) are hybrids crystalline compounds made up of clusters (or chains) of metal ions coordinated by organic linkers to form three dimensional structures. The ability to vary these two entities offers to MOFs a wide variety of organized structure with pore sizes controlled. The aim of this thesis was to evaluate the MOF performances for the adsorption of organic compounds and also understand the related adsorption mechanism. The two selected issues are of interest for the petrochemical industry. The para-xylène separation from the other xylene isomers (ortho, meta) and ethylbenzene, allows to meet the demand for raw materials in the polyethylene terephthalate (PET) synthesis. The nitrogen and sulphur compounds adsorption allows the purification of fuels (sulphur content set by legislation). We present a thermodynamic study of adsorption from solution based on the determination of adsorption isotherms by depletion method and adsorption enthalpies by microcalorimetry. The pure xylenes vapour adsorption was also studied to understand the solvent effect. A wide variety of behaviour has been observed depending on MOF structures. For example we demonstrated the effect of xylene isomers molecular packing on MOF selectivity. Furthermore we have shown that the MOF structure flexibility influence the interactions involved during xylene isomers adsorption. We also demonstrated that MOF with unsaturated metallic centres present selectivity for nitrogen compounds (Lewis acid/base).
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Synthèse de catalyseurs de type coeur@coquille pour le procédé d’hydrodésulfuration en phase gazeuse / Synthesis of core shell catalysts for hydrodesulfurization processWery, Madeleine 26 September 2018 (has links)
Afin de réduire la teneur en soufre des essences, l’hydrodésulfuration transforme les molécules soufrées en hydrocarbures en présence d’un catalyseur supporté (métaux de transition sulfurés : MoS2) et dopé (Co, Ni). Cette phase active, déposée sur des nanoparticules, présente un nombre plus important de défauts, sites actifs essentiels à la catalyse. Les nanoparticules ont un ratio S/V élevé, une grande réactivité de surface avec une juste utilisation des quantités de métaux. L’objectif de ce projet de thèse est de synthétiser des catalyseurs nanométriques de type coeur@coquille possédant une meilleure activité catalytique qu’un simple mélange mécanique de deux métaux sulfurés. Le coeur est composé de Fe3O4 ou de nanodiamants et la coquille de MoS2, NiMoS, CoMoS ou NiCoMoS, supporté sur du TiO2 ou de la γ-Al2O3. Une réaction modèle (HDS du thiophène) a été utilisée afin d’évaluer l’activité catalytique et d’optimiser la structure du catalyseur. L’étude portera sur les paramètres de synthèse et l’effet de la taille du coeur, la synthèse utilisée, les interactions entre le coeur et la coquille, le support, la (co)– promotion (Ni/Co) et l’activation par la température. / In hydrodesulfurization of fossil fuels, the sulfur levels are reduced by sulfur extraction from hydrocarbons by using supported catalysts (MoS2), doped (Co, Ni). Ultra-deep hydrodesulfurization will be achieved by improving new catalysts. Nanoparticles are a promising candidate with their high S/V ratio and permit to use the precise amount of metallic sulphide. The aim of this thesis is the synthesis of core@shell nanometric catalyst with improved activities. Core composed of Fe3O4 or nanodiamonds will be surrounded by a shell formed of MoS2, NiMoS, CoMoS or NiCoMoS, supported on TiO2, γ-Al2O3. Model reaction (thiophene) has allowed to compare conversion rates between each catalyst. Additionally, characterizations have provided a better understanding of the HDS catalyst structure and performances. Some factors have been investigated such as the size of the core, theinteractions between the core and the shell, the type of synthesis, the support chosen, the synergetic effect with doping ions and also the activation of the catalyst at low temperature.
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Kinetic and Deactivation Studies of Hydrodesulfurization CatalystsSteiner, Petr January 2002 (has links)
<p>Hydrodesulfurization is an important part of the hydrotreating process. More stringent regulations on the quality of fuels bring new requirements to the catalytic processes. The removal of sulfur has become a key issue in the oil refining and this work aims to address several aspects of the process.</p><p>Kinetic studies of the hydrodesulfurization reaction over conventional (molybdenum-based) and new (Pt/Y-zeolite) catalysts are reported. The hydrodesulfurization of both the real oil (light gas oil from Statoil Mongstad refinery) and model compounds (thiophene and dibenzothiophene) over a NiMo/γ-Al<sub>2</sub>O<sub>3</sub> catalyst were studied. In a high-pressure study of the light gas oil, substituted alkyl-DBTs were found to be the most difficult to desulfurize and the order of reactivity was found to be DBT > 4-MDBT > 4,6-DMDBT. Steric hindrance together with electronic effects were identified as possible reasons for this behavior. The difference in reactivities of the individual compounds was found to decrease with the increasing reaction temperature. A gas chromatograph equipped with the atomic emission detector (GC-AED) was used for the analysis of the individual components of the oil.</p><p>The initial deactivation and the steady-state kinetics were studied during the HDS of thiophene at atmospheric pressure. Unpromoted Mo/γ-Al<sub>2</sub>O<sub>3</sub>, CoMo/γ-Al<sub>2</sub>O<sub>3</sub>, NiMo/γ-Al<sub>2</sub>O<sub>3</sub>, and phosphorus modified NiMo/γ-Al<sub>2</sub>O<sub>3</sub> were used for the deactivation study, while NiMo/γ-Al<sub>2</sub>O<sub>3</sub>,CoMo/γ-Al<sub>2</sub>O<sub>3</sub>, and Pt/Y-zeolite (with three different pretreatments) were used for the steadystate study. Several experiments related to the deactivation of Mo/γ-Al<sub>2</sub>O<sub>3</sub> and NiMo/γ-Al<sub>2</sub>O<sub>3 </sub>catalysts prepared with the chelating agent (NTA) were also performed and NTA was found to have no significant effect on the activity of the catalysts.</p><p>In the deactivation study, a fast initial decrease in the activity was observed on all the catalysts. However, nickel promoted catalysts were found to be more resistant to deactivation than unpromoted ones. The presence of phosphorus slightly increased the activity of the catalyst towards the thiophene HDS, but had no effect on the deactivation behavior. Several methods to regenerate the catalyst were investigated. During the resulfiding experiments, a difference between Mo/γ-Al<sub>2</sub>O<sub>3</sub> and NiMo/γ-Al<sub>2</sub>O<sub>3</sub> was observed. Deactivation of the Mo catalyst was more severe with increasing temperature, while for the NiMo catalyst the opposite behavior was observed. Carbon deposition on catalysts followed the similar trend: More carbon was observed on the Mo catalyst at higher temperatures, while the opposite is true for NiMo. The restoration of the activity of NiMo was complete, while the reactivation of the Mo catalyst was only partial. The results from the reactivation experiments with pure H<sub>2</sub> and inert gas (helium) suggest that several mechanisms of the restoration of activity exist: Resulfiding of the desulfided active sites, hydrogenation and removal of the deposited carbonaceous species, and the desorption of the reactants and products from the active sites of the catalyst. Based on the observed results, the higher hydrogenation activity of nickel is assumed to be the reason for the behavior. Hydrogenation causes the faster removal of the deposited carbonaceous species and this leads to the conclusion that the desulfiding of the active sites and the adsorption of the reaction species is significantly less pronounced on the NiMo/γ-Al<sub>2</sub>O<sub>3 </sub>catalyst.</p><p>Characterization studies show differences between standard and NTA-based catalysts. The higher amount of carbon on the NTA catalysts is attributed to the presence of the carboncontaining precursor - NTA. The changes in the surface area and the pore volume were observed only during the sulfiding process. In the case of standard catalysts the surface area and the pore volume decreased, while for the NTA-based catalysts the opposite is true. No change in the surface area and the pore volume with the increasing time on stream indicates that the deactivation is not due to structural changes of the catalyst. The amount of sulfur was found to be constant during the time on stream for all the catalysts.</p><p>In the steady-state study of the HDS of thiophene, CoMo and NiMo catalysts were found to be equally active. The activity of the Pt/Y-zeolite catalyst was found to be comparable to conventional catalysts when based on the amount of active material, but a fast deactivation was observed. The product selectivities during the HDS of thiophene were found to be the same for all standard catalysts, but slightly different for the Pt/Y-zeolite catalyst. This was attributed to a higher hydrogenation activity of the Pt/Y-zeolite catalyst. </p><p>The inhibition effect of other sulfur compounds and aromatics on the high-pressure hydrodesulfurization of dibenzothiophene (DBT), the so-called “matrix effect” was studied. Thiophene and DMDS have the same inhibiting effect on the total conversion of DBT, but differences exist in the effect on the selectivities of the products at low concentrations. The results indicate that the inhibiting effect of H<sub>2</sub>S on the direct desulfurization route is stronger than the effect of thiophene on the hydrogenation pathway. In the study of aromatics, both toluene and naphthalene affect the total conversion of DBT. Naphthalene was found to be a much stronger inhibitor and inhibits mainly the direct desulfurization pathway, while the hydrogenation route is more affected by the presence of toluene.</p>
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Kinetic and Deactivation Studies of Hydrodesulfurization CatalystsSteiner, Petr January 2002 (has links)
Hydrodesulfurization is an important part of the hydrotreating process. More stringent regulations on the quality of fuels bring new requirements to the catalytic processes. The removal of sulfur has become a key issue in the oil refining and this work aims to address several aspects of the process. Kinetic studies of the hydrodesulfurization reaction over conventional (molybdenum-based) and new (Pt/Y-zeolite) catalysts are reported. The hydrodesulfurization of both the real oil (light gas oil from Statoil Mongstad refinery) and model compounds (thiophene and dibenzothiophene) over a NiMo/γ-Al2O3 catalyst were studied. In a high-pressure study of the light gas oil, substituted alkyl-DBTs were found to be the most difficult to desulfurize and the order of reactivity was found to be DBT > 4-MDBT > 4,6-DMDBT. Steric hindrance together with electronic effects were identified as possible reasons for this behavior. The difference in reactivities of the individual compounds was found to decrease with the increasing reaction temperature. A gas chromatograph equipped with the atomic emission detector (GC-AED) was used for the analysis of the individual components of the oil. The initial deactivation and the steady-state kinetics were studied during the HDS of thiophene at atmospheric pressure. Unpromoted Mo/γ-Al2O3, CoMo/γ-Al2O3, NiMo/γ-Al2O3, and phosphorus modified NiMo/γ-Al2O3 were used for the deactivation study, while NiMo/γ-Al2O3,CoMo/γ-Al2O3, and Pt/Y-zeolite (with three different pretreatments) were used for the steadystate study. Several experiments related to the deactivation of Mo/γ-Al2O3 and NiMo/γ-Al2O3 catalysts prepared with the chelating agent (NTA) were also performed and NTA was found to have no significant effect on the activity of the catalysts. In the deactivation study, a fast initial decrease in the activity was observed on all the catalysts. However, nickel promoted catalysts were found to be more resistant to deactivation than unpromoted ones. The presence of phosphorus slightly increased the activity of the catalyst towards the thiophene HDS, but had no effect on the deactivation behavior. Several methods to regenerate the catalyst were investigated. During the resulfiding experiments, a difference between Mo/γ-Al2O3 and NiMo/γ-Al2O3 was observed. Deactivation of the Mo catalyst was more severe with increasing temperature, while for the NiMo catalyst the opposite behavior was observed. Carbon deposition on catalysts followed the similar trend: More carbon was observed on the Mo catalyst at higher temperatures, while the opposite is true for NiMo. The restoration of the activity of NiMo was complete, while the reactivation of the Mo catalyst was only partial. The results from the reactivation experiments with pure H2 and inert gas (helium) suggest that several mechanisms of the restoration of activity exist: Resulfiding of the desulfided active sites, hydrogenation and removal of the deposited carbonaceous species, and the desorption of the reactants and products from the active sites of the catalyst. Based on the observed results, the higher hydrogenation activity of nickel is assumed to be the reason for the behavior. Hydrogenation causes the faster removal of the deposited carbonaceous species and this leads to the conclusion that the desulfiding of the active sites and the adsorption of the reaction species is significantly less pronounced on the NiMo/γ-Al2O3 catalyst. Characterization studies show differences between standard and NTA-based catalysts. The higher amount of carbon on the NTA catalysts is attributed to the presence of the carboncontaining precursor - NTA. The changes in the surface area and the pore volume were observed only during the sulfiding process. In the case of standard catalysts the surface area and the pore volume decreased, while for the NTA-based catalysts the opposite is true. No change in the surface area and the pore volume with the increasing time on stream indicates that the deactivation is not due to structural changes of the catalyst. The amount of sulfur was found to be constant during the time on stream for all the catalysts. In the steady-state study of the HDS of thiophene, CoMo and NiMo catalysts were found to be equally active. The activity of the Pt/Y-zeolite catalyst was found to be comparable to conventional catalysts when based on the amount of active material, but a fast deactivation was observed. The product selectivities during the HDS of thiophene were found to be the same for all standard catalysts, but slightly different for the Pt/Y-zeolite catalyst. This was attributed to a higher hydrogenation activity of the Pt/Y-zeolite catalyst. The inhibition effect of other sulfur compounds and aromatics on the high-pressure hydrodesulfurization of dibenzothiophene (DBT), the so-called “matrix effect” was studied. Thiophene and DMDS have the same inhibiting effect on the total conversion of DBT, but differences exist in the effect on the selectivities of the products at low concentrations. The results indicate that the inhibiting effect of H2S on the direct desulfurization route is stronger than the effect of thiophene on the hydrogenation pathway. In the study of aromatics, both toluene and naphthalene affect the total conversion of DBT. Naphthalene was found to be a much stronger inhibitor and inhibits mainly the direct desulfurization pathway, while the hydrogenation route is more affected by the presence of toluene.
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Thiophen und Benzodithiophen basierte organische Halbleiter für aus Lösung prozessierbare Feldeffekttransistoren / Thiophene and benzodithiophene based organic semiconductors for solution processable field effect transistorsBilkay, Taybet January 2013 (has links)
Diese Arbeit befasst sich mit der Synthese und Charakterisierung von organolöslichen Thiophen und Benzodithiophen basierten Materialien und ihrer Anwendung als aktive lochleitende Halbleiterschichten in Feldeffekttransistoren.
Im ersten Teil der Arbeit wird durch eine gezielte Modifikation des Thiophengrundgerüstes eine neue Comonomer-Einheit für die Synthese von Thiophen basierten Copolymeren erfolgreich dargestellt. Die hydrophoben Hexylgruppen in der 3-Position des Thiophens werden teilweise durch hydrophile 3,6-Dioxaheptylgruppen ersetzt. Über die Grignard-Metathese nach McCullough werden statistische Copolymere mit unterschiedlichen molaren Anteilen vom hydrophoben Hexyl- und hydrophilem 3,6-Dioxaheptylgruppen 1:1 (P-1), 1:2 (P-2) und 2:1 (P-3) erfolgreich hergestellt. Auch die Synthese eines definierten Blockcopolymers BP-1 durch sequentielle Addition der Comonomere wird realisiert. Optische und elektrochemische Eigenschaften der neuartigen Copolymere sind vergleichbar mit P3HT. Mit allen Copolymeren wird ein charakteristisches Transistorverhalten in einem Top-Gate/Bottom-Kontakt-Aufbau erhalten. Dabei werden mit P-1 als die aktive Halbleiterschicht im Bauteil, PMMA als Dielektrikum und Silber als Gate-Elektrode Mobilitäten von bis zu 10-2 cm2/Vs erzielt. Als Folge der optimierten Grenzfläche zwischen Dielektrikum und Halbleiter wird eine Verbesserung der Luftstabilität der Transistoren über mehrere Monate festgestellt.
Im zweiten Teil der Arbeit werden Benzodithiophen basierte organische Materialien hergestellt. Für die Synthese der neuartigen Benzodithiophen-Derivate wird die Schlüsselverbindung TIPS-BDT in guter Ausbeute dargestellt. Die Difunktionalisierung von TIPS-BDT in den 2,6-Positionen über eine elektrophile Substitution liefert die gewünschten Dibrom- und Distannylmonomere. Zunächst werden über die Stille-Reaktion alternierende Copolymere mit alkylierten Fluoren- und Chinoxalin-Einheiten realisiert. Alle Copolymere zeichnen sich durch eine gute Löslichkeit in gängigen organischen Lösungsmitteln, hohe thermische Stabilität und durch gute Filmbildungseigenschaften aus. Des Weiteren sind alle Copolymere mit HOMO Lagen höher als -6.3 eV, verglichen mit den Thiophen basierten Copolymeren (P-1 bis P-3), sehr oxidationsstabil.
Diese Copolymere zeigen amorphes Verhalten in den Halbleiterschichten in OFETs auf und es werden Mobilitäten bis zu 10-4 cm2/Vs erreicht. Eine Abhängigkeit der Bauteil-Leistung von dem Zinngehalt-Rest im Polymer wird nachgewiesen. Ein Zinngehalt von über 0.6 % kann enormen Einfluss auf die Mobilität ausüben, da die funktionellen SnMe3-Gruppen als Fallenzustände wirken können. Alternativ wird das alternierende TIPS-BDT/Fluoren-Copolymer P-5-Stille nach der Suzuki-Methode polymerisiert. Mit P-5-Suzuki als die aktive organische Halbleiterschicht im OFET wird die höchste Mobilität von 10-2 cm2/Vs erzielt. Diese Mobilität ist somit um zwei Größenordnungen höher als bei P-5-Stille, da die Fallenzustände in diesem Fall minimiert werden und folglich der Ladungstransport verbessert wird.
Sowohl das Homopolymer P-12 als auch das Copolymer mit dem aromatischen Akzeptor Benzothiadiazol P-9 führen zu schwerlöslichen Polymeren. Aus diesem Grund werden einerseits Terpolymere aus TIPS-BDT/Fluoren/BTD-Einheiten P-10 und P-11 aufgebaut und andererseits wird versucht die TIPS-BDT-Einheit in die Seitenkette des Styrols einzubringen. Mit der Einführung von BTD in die Hauptpolymerkette werden insbesondere die Absorptions- und die elektrochemischen Eigenschaften beeinflusst. Im Vergleich zu dem TIPS-BDT/Fluoren-Copolymer reicht die Absorption bis in den sichtbaren Bereich und die LUMO Lage wird zu niederen Werten verschoben. Eine Verbesserung der Leistung in den Bauteilen wird jedoch nicht festgestellt. Die erfolgreiche erstmalige Synthese von TIPS-BDT als Seitenkettenpolymer an Styrol P-13 führt zu einem löslichen und amorphen Polymer mit vergleichbaren Mobilitäten von Styrol basierten Polymeren (µ = 10-5 cm2/Vs) im OFET.
Ein weiteres Ziel dieser Arbeit ist die Synthese von niedermolekularen organolöslichen Benzodithiophen-Derivaten. Über Suzuki- und Stille-Reaktionen ist es erstmals möglich, verschiedenartige Aromaten über eine σ-Bindung an TIPS-BDT in den 2,6-Positionen zu knüpfen. Die UV/VIS-Untersuchungen zeigen, dass die Absorption durch die Verlängerung der π-Konjugationslänge zu höheren Wellenlängen verschoben wird. Darüber hinaus ist es möglich, thermisch vernetzbare Gruppen wie Allyloxy in das Molekülgerüst einzubauen. Das Einführen von F-Atomen in das Molekülgerüst resultiert in einer verstärkten Packungsordnung im Fluorbenzen funktionalisiertem TIPS-BDT (SM-4) im Festkörper mit sehr guten elektronischen Eigenschaften im OFET, wobei Mobilitäten bis zu 0.09 cm2/Vs erreicht werden. / This work describes the synthesis and characterization of organo-soluble thiophene and benzodithiophene based materials and their application as hole-transporting active semiconductor layers in field effect transistors.
The first part of this work introduces the targeted modification of the thiophene base unit, obtaining new comonomers for the corresponding copolymers.
The hydrophobic hexyl groups in the 3-position of thiophene are partially replaced by hydrophilic 3,6-Dioxaheptyl groups. Using the Grignard metathesis developed by
McCullough, statistical copolymers with different molar ratios of hydrophobic and hydrophilic side groups 1:1 (P-1), 1:2 (P-2) and 2:1 (P-3) are synthesized. Furthermore a defined blockcopolymer is synthesized by a sequential comonomer addition. Optical and electrochemical properties of the novel copolymers are comparable to the homopolymer P3HT. All copolymers show clearly transistor characteristics in a top-gate/bottom-contact configuration. Devices with P-1 as active semiconductor layer, PMMA as dielectric and silver as the gate electrode show mobilities up to 10-2 cm2/Vs. As a result of the optimized semiconductor and dielectric interface an improvement of the air stability of the transistors is observed for several months.
The second part describes the synthesis of benzodithiophene based organic materials. For the synthesis of the novel benzodithiophene-derivatives the key intermediate TIPS-BDT is obtained in high yields. A difunctionalization of TIPS-BDT in 2,6-position is observed by electrophilic substitution reactions and provided the desired dibromo- and distannyl-monomers. Via Stille-reaction alternated copolymers with alkylated fluorene and quinoxaline groups are synthesized. All copolymers are soluble in common organic solvents, show high thermal stability and good film forming properties. Furthermore all copolymers have HOMO values above -6.3 eV and are more oxidation stable compared to the thiophene based copolymers (P-1 up to P-3).
These copolymers show an amorphous behavior as semiconductor layer in OFETs and mobilities up to 10-4 cm2/Vs are observed. A correlation between the device performance and the tin amount in the polymer could be demonstrated. Hence the functional SnMe3 groups can act as traps, a tin amount higher than 0.6 % can negatively influence the mobility. Alternatively the alternated TIPS-BDT/Fluoren-copolymer P-5-Stille is polymerized by the Suzuki-Method. The highest mobility of 10-2 cm2/Vs is obtained with P-5-Suzuki as active semiconductor layer in OFET. In comparison to P-5-Stille this mobility is two orders of magnitude higher, because in P-5-Suzuki traps are minimized and the charge transfer is improved.
The synthesis of homopolymer P-12 as well as the copolymer with aromatic benzothiadiazole P-9 resulted in insoluble polymers. For this reason terpolymers containing TIPS-BDT/Fluoren/BTD units are designed. Additionally an attempt has been made to introduce the TIPS-BDT unit in the side chain of styrene. The introduction of BTD in the conjugated main chain influences especially the absorption and electrochemical properties. Compared to TIPS-BDT/Fluoren-copolymer the absorption of the terpolymer is shifted to the visible region and the LUMO values decreased. An improvement in the device performance is not observed. A side chain polystyrene containing TIPS-BDT P-13 is synthesized successfully. The amorphous and soluble P-13 showed comparable mobilities (µ = 10-5 cm2/Vs) as known styrene based polymers.
A further aim of this work is the synthesis of organo-soluble benzodithiophene based small molecules. Using Suzuki- and Stille-reactions different aromatic cores as endcappers are connected by σ-bonds at the 2,6-position of TIPS-BDT. UV/VIS-measurements show a red-shift of the absorption maxima with extension of the π-conjugated system. Furthermore it is possible to introduce thermal cross linkable allyloxy-groups. The F-atoms in the molecule lead to stronger intermolecular interactions in the solid state, which improves the electronic properties and lead to high mobilities up to 0.09 cm2/Vs for TIPS-BDT (SM-4).
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S?ntese e caracteriza??o de catalisadores nanom?tricos de LaSrNiO4 para aplica??o em dessulfuriza??o de tiofenoSousa, Karla Silvana Menezes Gadelha de 13 March 2009 (has links)
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Previous issue date: 2009-03-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The mixed metal oxides constitute an important class of catalytic materials widely investigated in different fields of applications. Studies of rare earth nickelates have
been carried by several researchers in order to investigate the structural stability afforded by oxide formed and the existence of catalytic properties at room temperature. So, this study aims synthesize the nanosized catalyst of nickelate of lanthanum doped with strontium (La(1-x)SrxNiO4-d; x = 0,2 and 0,3), through the Pechini method and your characterization for subsequent application in the
desulfurization of thiophene reaction. The precursor solutions were calcined at 300?C/2h for pyrolysis of polyester and later calcinations occurred at temperatures of 500 - 1000?C. The resulting powders were characterized by thermogravimetric
analysis (TG / DTG), surface area for adsorption of N2 by BET method, X-ray diffraction (XRD), scanning electron microscopy (HR_SEM) and spectrometry dispersive energy (EDS). The results of XRD had show that the perovskites obtained consist of two phases (LSN and NiO) and from 700?C have crystalline structure. The results of SEM evidenced the obtainment of nanometric powders. The results of BET
show that the powders have surface area within the range used in catalysis (5-50m2/g). The characterization of active sites was performed by reaction of desulfurization of thiophene at room temperature and 200?C, the relation F/W equal to 0,7 mol h-1mcat -1. The products of the reaction were separated by gas chromatography and identified by the selective detection PFPD sulfur. All samples had presented conversion above 95% / Os ?xidos met?licos mistos constituem uma importante classe de materiais catal?ticos mundialmente investigados em diferentes campos de aplica??es. Estudos envolvendo niquelatos de terras raras v?m sendo realizados por v?rios
pesquisadores no intuito de investigar a estabilidade proporcionada pelo ?xido estrutural formado e a exist?ncia de propriedades catal?ticas, ? temperatura ambiente. Neste contexto, este trabalho tem como objetivo a s?ntese do catalisador nanom?trico de niquelato de lant?nio dopado com estr?ncio (La(1-x)SrxNiO4-d; x = 0,2 e 0,3), atrav?s do m?todo Pechini e caracteriza??o para posterior aplica??o em
rea??o de dessulfuriza??o de tiofeno. As solu??es precursoras foram calcinadas a 300?C/2h, para pir?lise do poli?ster e posteriores calcina??es foram realizadas nas temperaturas entre 500 - 1000?C. Os p?s resultantes foram caracterizados por an?lise termogravim?trica (TG/DTG), ?rea superficial por adsor??o de N2 pelo m?todo BET, difra??o de raios x (DRX), microscopia eletr?nica de varredura de alta resolu??o (HR_MEV) e espectroscopia por energia dispersiva (EDS). Com os dados de an?lise t?rmica, foi poss?vel definir as temperaturas e calores envolvidos no processo de decomposi??o dos ?xidos finais. Os resultados de DRX mostraram que as perovisquitas obtidas s?o constitu?das de duas fases (LSN e NiO) e a partir de 700?C apresentaram estrutura cristalina. Os resultados de MEV evidenciaram a
obten??o de p?s nanom?tricos. Os resultados de BET mostraram que os p?s obtidos apresentam ?rea superficial dentro da faixa utilizada em cat?lise (5-50m2/g). A
caracteriza??o dos s?tios ativos foi realizada atrav?s da rea??o de dessulfuriza??o de tiofeno ? temperatura ambiente e a 200oC, com raz?o F/W igual a 0,7molh-1mcat
-1. Os produtos da rea??o foram separados por cromatografia em fase gasosa e identificados por detec??o PFPD seletivo a enxofre. Todas as amostras apresentaram convers?o acima de 95%
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Synthèses et évaluations biologiques d’analogues de la combrétastatine A-4 et d’inhibiteurs de kinases DYRK / Syntheses and biological evaluations of combretastatine A-4 analogs and DYRK kinases inhibitorsFaouzi, Abdelfattah 17 November 2017 (has links)
En 2015, on estime le nombre de nouveaux cas de cancer à plus de 385000 et le nombre de décès à 149500. Ces chiffres, plus élevés chez l'homme que chez la femme, connaissent ces dernières années une nette recrudescence chez les patients de sexe féminin. Globalement, la principale difficulté pour lutter contre les cancers se situe dans la capacité à les détecter avant qu'ils ne métastasent et dans les nombreux phénomènes de résistance aux traitements chimiothérapeutiques.De par son implication dans la croissance des cellules cancéreuses, le réseau vasculaire tumorale représente une cible intéressante ainsi qu'une alternative prometteuse aux traitements actuels. Ainsi, la classe de composés qualifiés de VDAs (pour « Vascular Disrupting Agents ») visent les cellules endothéliales ainsi que les péricytes, provoquant ainsi des phénomènes d'ischémie et de nécrose cellulaire. Un exemple de ce type de composés n'est autre que la Combrétastatine A-4 (ou CA-4), qui est un composé naturel extrait d'un arbuste sud-africain, le Combretum caffrum. Cette molécule a été pour la première fois étudiée par G.R. Pettit en 1989 qui a alors démontré qu'elle pouvait inhiber très efficacement la polymérisation des dimères α et β de tubuline en microtubules, résultant alors en la non-formation du cytosquelette, et l'apoptose de la cellule. Le développement de nouveaux analogues de la CA-4 s'avère crucial car ce composé dispose non seulement d'une solubilité réduite mais peut aussi être instable lorsqu'il est administré. Le travail effectué lors de cette thèse a donc consisté dans un premier temps en la synthèse de nouveaux dérivés de la CA-4 en remplaçant le noyau B par différents hétérocycles et en effectuant plusieurs pharmacomodulations ; ces derniers étant alors évalués pour leurs propriétés inhibitrices de la polymérisation de la tubuline et antiprolifératives. Avec plus de 24 millions de personnes touchées dans le monde, les pathologies neurodégénératives représentent un problème majeur de santé publique. Il est également très important de considérer l'incidence future de ces pathologies, et on estime à plus de 42 millions le nombre de personnes qui seraient atteintes par ce fléau d'ici à 2020. La famille des protéines kinases DYRK a fait l'objet ces dernières années d'une attention toute particulière de par son implication dans de nombreux phénomènes physiologiques et notamment au niveau des phases primaires du développement du système nerveux central. Plus spécifiquement, les kinases DYRK1A et DYRK1B ont été étudiées de par leurs implications dans de nombreux cancers (notamment le glioblastome) et certaines pathologies neurocérébrales. Le dérèglement de l'expression de ces protéines pourrait être la cause de retards mentaux, du développement de la maladie d'Alzheimer, de la trisomie 21, ainsi que de phénomènes de résistance. Nous avons identifié au sein de notre laboratoire une molécule inhibant ces 2 kinases. Initialement développé dans le but d'inhiber la protéine kinase CK2 (caséine kinase 2), notre composé a montré une activité inhibitrice et une sélectivité sur DYRK1A et DYRK1B. De par son activité, cette molécule est aujourd'hui notre composé « hit » et nous visons, à travers les travaux de cette thèse, la synthèse de multiples analogues dans le but d'améliorer l'activité initiale mais aussi sa spécificité sur DYRK1A ou sur DYRKB. Dans cette optique, nous avons réalisé différentes pharmacomodulations de nos composés dits « indénobenzo[b]thiophènes » et étudier les effets de tels composés sur DYRK1A, DYRK1B, DYRK2 mais aussi sur CK2. Ceci nous a permis d'affiner nos connaissances vis-à-vis des kinases de type DYRK et de sélectionner les molécules les plus prometteuses afin de (i) réaliser une étude autour de leurs caractéristiques physico-chimiques (Log P, solubilités dans différents solvants), (ii) d'analyser leurs comportements au niveau de la barrière hémato-encéphalique (BHE) et (iii) de réaliser des nano-encapsulations / Up to now, cancer is the second deadliest pathology in the World and is still considered as one of the most challenging public health issue. Globally, it has been assessed to be the main pathologic cause of death by the World Health Organization. This bad prognosis is partly due to the ability of cancer cells to give metastases but also to resistances phenomenon impeding drastically the effect of chemotherapeutic and radiotherapeutic treatments. As a consequence, there is currently a critical lack of effective treatments which would completely eradicate tumor cells, with minimal side effects. In spite of some difficulties in this competitive research area, the discovery of cancer therapeutics remains stimulating and we aim to achieve the synthesis of novel anticancer agents.Given its pivotal role in tumor growth and survival, the tumor vasculature represents an attractive target for anticancer therapy. Apart from angiogenesis inhibitors that compromise the formation of new blood vessels, the class of vascular disrupting agents (VDAs) targets endothelial cells and pericytes of the already established tumor vasculature, resulting in tumor ischemia and necrosis. A striking example of VDA is the combretastatin A-4, also known as CA-4, which was originally isolated from the bark of the South African willow tree Combretum caffrum by the American scientist G.R. Pettit in 1989. These products demonstrated to be efficient against a wide array of cancers such as breast, colon, lung or ovarian cell lines. New CA-4 analogs containing different heterocycles instead of the hydroxymethoxy substituted pharmacomodulable B ring were prepared and evaluated for their in cellulo tubulin polymerization inhibition and antiproliferative activities. In the other hand, tumor cell survival is a complex process which remains poorly understood. As part of the survival machinery, chemoresistances and DNA repairs are central elements regulated by a prosurvival/proapoptotic signal balance. Protein kinases are known to be directly involved in this signal transmission through molecular interactions. As such, DYRK kinases and most specifically DYRK1A/1B, were part of numerous recent studies due to their involvement in cancer and other pathologies. DYRK1B (also called Mirk kinase) is an ubiquitous kinase which was proved to be over-expressed in many cancers such as pancreatic, ovarian or colon. Its involvement as a regulator of DNA repair and tumor cell survival was assessed, phosphorylating specifically serine, threonine and tyrosine residues. Also, another closely related isoform known as DYRK1A, was mapped in the Down syndrome critical region located itself on chromosome 21. Interestingly, this kinase was not only uncovered to play a fundamental role in glioblastomas survival but was also associated with abnormal brain development in early stages and mental retardations. Particularly, DYRK1A was found to hyperphosphorylate microtubule-associated tau protein, resulting into genesis of neurofibrillary tangles. As a consequence, DYRK1A has become one of the most targeted proteins in order to improve cognitive impairment of patients suffering from Down syndrome or Alzheimer’s disease. Initially designed to target protein kinase CK2, one of our molecules was also tested on DYRK kinases. This compound exhibited a strong activity against DYRK1A/DYRK1B whilst being inactive on other protein kinases. Consequently, it was considered as our hit compound and (i) we synthetized derivatives as dual or single inhibitors of DYRK1A/DYRK1B, (ii) evaluated their biological activities (with emphasis on the blood brain barrier), and (iii) finally synthesized nanoparticles loaded with our inhibitors
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Morpological Architecturing of Electroactive Materials in Organic ElectronicsKhanum, Khadija Kanwal January 2015 (has links) (PDF)
Morphological architecturing is one of the smart and efficient ways to maximize the number of excitons harvested from the known photoactive materials and existing fabrication technologies. Surfaces and interfaces play a vital role in absorbing light and therefore when patterned regularly, aid in the improvement of light absorption. This thesis deals with the study of light management by morphologically architecturing the organic electroactive materials. Here, morphological architecturing is carried out using electrospinning technique by optimizing various parameters. In the first part, organic photovoltaic system is tailored by morphologically modifying the conjugated polymer active layer and analyzing the enhancement in light collection and hence performance of photovoltaic devices. In the second part, the prospects of using free standing buffer layer instead of thin film buffer layer in a solar cell is evaluated. Furthermore, the study on morphological engineering of conjugated small molecule is carried out, by varying the solvents and derivatives, in order to control morphologies by understanding the underlying mechanism. Overall this thesis attempts to understand the fundamentals in morphological architecturing, by physical architecturing of the small molecules in a device for light management applications as well as demonstrating improvement in light absorption in existing organic photovoltaic systems.
In the introduction chapter, a brief description of organic photovoltaics is given followed by highlighting the importance of processing methods in light management and in organic photovoltaics. The significance of structured architecture in improving the device characteristics is presented. The issues and challenges in existing architecturing techniques available in literature are discussed. Electrospinning as a tool for morphological modification for organic photovoltaics is demonstrated. This is followed by an outline of the thesis.
In Chapter 2, brief description of procedures carried out for fabrication, characterization and optimization of electrospinning process parameters are discussed. The description of fabrication procedures including electrospinning, spincoating and thermal evaporation are given. Characterization techniques used in this thesis for surface and feature analysis, structural, compositional, optical and opto-electrical analyses are described. Optimization of electrospinning process parameters in obtaining various morphologies are evaluated.
In Chapter 3, enhancement of device characteristics of poly (3-hexylthiophene): phenyl C61-butyric acid methyl ester (P3HT: PCBM) by changing active layer film morphology into network structure is elucidated. Network structure is provided by electrospraying assisted hierarchical assembly of short fibrils. Effect of electrospraying parameters such as solvent, polymer blend concentration, applied voltage, tip to collector distance, flow rate and deposition time are analyzed. Solvent and applied voltage are observed to be the major parameters governing the formation of network structure. The optimized conditions are used to investigate the optical and structural properties. Percent reflectance studies showed improvement in light absorption due to increase in surface area. Structural characterization studies indicate an increase in orientation of crystallites and crystallinity as compared to spincoated samples. The optimized conditions along with additional spincoated layer of P3HT:PCBM are used to fabricate bulk heterojunction device. Device characteristics exhibited an increase in short circuit current and thus increase in efficiency from 2.18% to 3.66%. There is a enhancement of 37.5% going from maximum external quantum efficiency of 40%-55% for electrosprayed and spincoated devices. It is anticipated that network morphology could be the next possible structure to be explored in organic photovoltaic materials.
In Chapter 4, photonic structure is analyzed and compared. A photonics device requires uniform periodic structural arrangement. Various techniques are used to fabricate these types of structures, employing several steps of fabrication. This work proposes single step hierarchical array of equal submicron size porous structure fabricated by tuning electrospinning processing parameters. The dictating process parameters on evolving structure are high voltage, tip to collector distance and solvent. Morphological and optical investigations suggest that uniform periodic topography helps in light scattering leading to multi reflection and thus enhancement in light absorption. This structure is evaluated as active layer in organic photovoltaic devices using poly (3 hexyl thiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) blend and its device characteristics are analyzed. Consistent and reliable device characteristics obtained through photonic structure is demonstrated. Finally, comparison is drawn to network structure to assess the advantages and limitations of both morphologies as active layer in organic photovoltaics.
In Chapter 5, instead of architecturing active layer the next polymer film layer in the organic solar cells, that is the hole transport layer is transformed into free standing nanofiber mats. Morphological, structural and surface wetting properties are assessed for these nanofiber mats followed by fabrication of inverted organic solar cell. The free standing nanofibers mats are obtained by electrospinning the blend of Poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS) a conducting water soluble polymer with other water soluble polymers such as poly vinyl alcohol (PVA) and poly ethylene oxide (PEO). The study is further extended by employing two batches of PEDOT:PSS of varying conductivity that are analyzed side by side for six ternary and two binary blends each. Electrospinning parameters such as applied voltage and flow rate are optimized and fibers of diameter 150-200 nm are obtained. Maximum content of PEDOT:PSS with which free standing fiber mats could be achieved are 98 and 99%. Subsequent increase in PEDOT:PSS results in formation of beads. Surface wetting behavior showed that hydrophillicity increases with increase in PEDOT:PSS content. Devices are fabricated and the variation in characteristics and charge collection with respect to addition of PEO and PVA are discussed.
In Chapter 6, a conjugated small molecule is taken as case study unlike the use of the conjugated polymer studies in previous chapters. A mechanism is proposed for tuning the sphere-spike morphology and also to control the crystallite size through solvent management using a conjugated small molecule. Electrospraying of an organic molecule is carried out using various solvents, obtaining fibril structures along with a range of distinct morphologies. Solvent characteristics play a major role in achieving the morphology of the organic material. A thiophene derivative (7, 9-di (thiophen-2-yl)-8H-cyclopenta [a]acenaphthylen-8-one) (DTCPA) of donor-acceptor-donor (DAD) architecture is used to study this solvent effect. Seven solvents with decreasing vapor pressure are selected for experiments. Electrospraying is conducted at a solution concentration of 1.5 wt % and a constant applied voltage of 15 kV. Gradual transformation in morphology of the electrospun product from spikes-sphere to only spikes is observed. A mechanism describing this transformation is proposed based on the electron micrograph analysis and XRD analysis. These data indicate that the morphological change is due to the synergistic effect of both vapor pressure and dielectric constant of the solvents. Through a reasonable control over the crystallites size and morphology along with supporting transformation mechanism theory, the work in this chapter elucidates electrospraying as a prospective method for designing the architectures in organic electronics.
In Chapter 7, light management studies are carried out by morphologically architecturing the carbazole derivatives through electrospraying. The effect of derivatives on morphology is analyzed. The two carbazole derivatives; carbazole-benzothiadiazole (Cz-Bz) resulted in 2D structures and carbazole-benzothiadiazole-bithiophene (Cz-Bz-Bt) resulted in 3D structures after electrospraying. These structures are further analyzed to study the effect of vapor pressure of solvents and solution concentration. Structural characteristics indicate that electrospraying imparts change in molecular structure orientation. Optical studies showed 19 – 31% enhancement in light absorption. Further, three types of organic photovoltaic devices are fabricated and the opto-electrical properties are evaluated. Also, the effect of substrate on morphological formation is assessed.
In Chapter 8, the major contributions and conclusions drawn from the morphological architecturing of both conjugated polymers and small molecules are summarized, along with few recommendations for future research.
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