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Hélicènes photo-et redox actifs : Molécules uniques et auto-assemblage sur surface / Photo and redox active helicenes : Single molecules & surface self-assemblyMartin, Kévin 03 December 2018 (has links)
La conception de nouvelles molécules chirales est depuis plusieurs décennies un enjeu majeur. Ces travaux ont porté sur la synthèse ainsi que la caractérisation de diverses molécules à base d’hélicènes. En effet, les hélicènes sont chiraux et présentent des propriétés chiroptiques exceptionnelles. Ainsi, la combinaison de ces entités chirales associées à divers motifs permet la modulation de ces propriétés. Dans une première partie de ce manuscrit, nous nous sommes intéressés à l’association des hélicènes avec le motif tétrathiafulvalène (TTF) associant ainsi les propriétés redox du TTF à la chiralité des hélicènes. Une seconde partie concerne la préparation d’hélicènes luminescents à base de benzothiadiazole et de BODIPY avec pour objectif l’émission de lumière circulairement polarisée (CPL). Dans une troisième partie, nous avons étudié l’autoassemblage et la réactivité des motifs hélicéniques sur différentes surfaces de cuivre ou d’or. Enfin, nous avons réalisé des jonctions moléculaires à base d’hélicènes comme molécules uniques. En conclusion, nous avons développé différents motifs chiraux redox et photo-actifs ainsi que la formation de domaines auto-assemblés et des jonctions moléculaires à base d’hélicènes. / The development of new chiral molecules is a major challenge since few decades. This PhD work focuses on the synthesis and the characterisation of a variety of molecules based on helicenes. Indeed, helicenes are chiral and show exceptional chiroptical properties. Therefore, combining these chiral entities with various motifs allow the modulation of their properties. In a first part of this manuscript, we were interested in the association of helicenes with tetrathiafulvalene (TTF), thus combining the redox properties of TTF with the chirality of helicenes. The second part concerns the preparation of luminescent helicenes based on benzothiadiazole and BODIPY for circularly polarised light luminescence (CPL). In a third part we investigated the self-assembly and the reactivity of helicenes on gold and copper surfaces. Finally, we have prepared single molecule junctions based on helicenes. In Conclusion, we developed different redox and photoactive helicenes with applications towards the self-assembly on surfaces and single molecular junctions.
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Study on novel photochromic systems based on chromophores with six-membered ring as central ethene bridge / Etude de nouveaux systèmes photochromes basés sur des chromophores comportant un cycle à six atomes au niveau du pont éthène centralYang, Yuheng 05 June 2012 (has links)
Une série de bisthiényléthènes (BTE), chromophores photochromes, à différents ponts éthène centraux a été synthétisée. Jusque là, la conception rationnelle des BTE a reposé sur la nature des substituants des groupes latéraux. Dans notre travail, nous avons étudié l'influence de l'aromaticité du pont sur les propriétés photochromes. De plus, alors que les cycles à cinq atomes sont le plus souvent utilisés, nous avons introduit des cycles à six atomes au niveau de ce pont. Dans le Chapitre 1, les définitions principales liées au photochromisme, ainsi que des exemples, sont donnés. Le Chapitre 2 est dédié au BTTE, un BTE à pont benzobisthiadiazole, doté d'excellentes propriétés photochromes. Sa fluorescence peut être modulée par solvato- et photochromisme. c-BTTE, l'isomère fermé, a une excellente stabilité dans divers solvants et à l'état solide. Il ne présente pas de retour thermique typique des BTE à pont cyclique à six atomes. Le Chapitre 3 est consacré à des composés comportant des ponts de divers degrés d'aromaticité (BTE-NA, BTA et BTTA). Leur fluorescence peut être modulée par solvato- et photochromisme. Une faible aromaticité peut être corrélée à une irréversibilité thermique, comme illustré par le cas du BTTA à pont benzobisthiadiazole. De plus, la faible barrière énergétique entre les conformations parallèle et anti-parallèle et la grande différence d'absorption entre isomères conduisent à une conversion totale de BTTA à c-BTTA. Des molécules à pont benzothiadiazole, conçues pour la complexation et la commutation de propriétés optiques non linéaires, ont été obtenues (Chapitres 4 et 5). Cependant, pour l'instant, les propriétés visées n'ont pas été mises en évidence. / A series of photochromic bisthienylethenes (BTE) chromophores with different central ethene bridges were synthesized. Up to date, the rational design of BTE have been mainly carried out on the side aryl groups. In our work, the influence of the aromaticity of the central ethene bridge on the photochromic properties was studied. Moreover, unlike in the literature where most of BTE have a five-membered ring bridge, six-membered ring bridges were used. In Chapter 1, examples of photochromes are given, along with the main definitions. Chapter 2 deals with BTTE, a BTE with a benzobisthiadiazole bridge and with excellent photochromic properties. c-BTTE, the closed isomer, exhibits excellent thermal stability in various solvents and in the solid state. Its fluorescence can be modulated by solvato- and photochromism. It eliminates the usual bias of thermal back reaction, typical of BTE with a six-membered ring ethene bridge. Chapter 3 is devoted to compounds with bridges having different aromaticities (BTE-NA, BTA and BTTA). Their fluorescence can be modulated by solvato- and photochromism. The relation between aromaticity and thermal stability was established: the low aromaticity of the central ethene bridge with benzobisthiadiazole unit leads to a thermal irreversibility for BTTA, and the small energy barrier between the parallel and anti-parallel conformers and the great difference in absorption between BTTA and c-BTTA allow the full conversion from BTTA to c-BTTA. Molecules with a benzothiadiazole bridge, designed for complexation and for switchable nonlinear optical properties were prepared (Chapters 4 and 5). However, the targeted properties were not evidenced up to now.
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Synthesis and structure-properties relationship of alternated π-conjugated copolymers / Synthèse et relation structure-propriétés de copolymères alternés π-conjuguésOriou, Jules 10 December 2013 (has links)
Tout au long du siècle dernier, l’électronique s’est révélé être un progrès technologique majeur, et ses applications sont tellement nombreuses qu’elles ont envahi notre vie de tous les jours. De par leurs propriétés bien spécifiques, les semi-conducteurs organiques représentent une remarquable alternative aux matériaux inorganiques utilisés actuellement. Cependant, leurs propriétés électriques peuvent être limitées, et l’efficacité des dispositifs composés de tels matériaux ne permet pas encore de rivaliser avec ceux basés sur des matériaux inorganiques. Dans ce contexte, ce travail de thèse a pour objectif de synthétiser et caractériser de nouveaux polymères conjugués et d’étudier leurs propriétés, dans le but d’ajouter de nouveaux matériaux au déjà riche catalogue de polymères semi-conducteurs disponibles, ainsi que de permettre une meilleure compréhension de la relation structure-propriétés dans les systèmes conjugués. Des copolymères alternés composés de motifs carbazole, benzothiadiazole ou encore squaraine ont été synthétisés et caractérisés. De plus, des polymérisations originales et sans catalyseurs métalliques ont été développées. / Within the last century, electronics have become a major technological breakthrough and the resulting applications are so numerous that it has invaded our every-day life. Due to their properties, organic semiconductors have attracted much attention and represent a great alternative to the nowadays used inorganic materials. However, their electrical properties can be limited, and the efficiencies of the resulting devices are still not completely competitive against the inorganic-based ones. In this context, this PhD goal was to synthesize novel conjugated polymers (CPs) and investigate their properties, in order to add novel materials to the already wide catalogue of semiconducting polymers and allow a better comprehension of the structure-properties relationship in conjugated systems. Alternated copolymers based on carbazole, benzothiadiazole, or squaraine were synthesized and characterized. Furthermore, original and metal catalyst-free polymerizations were successfully developed.
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Combination Of Donor Characters In Donor-acceptor-donor Type Polymers Containing Benzothiadiazole And Quinoxaline As The Acceptor UnitsSendur, Merve 01 December 2011 (has links) (PDF)
Donor-acceptor-donor approach is one of the effective ways to synthesize low band gap polymers. The monomers that will be designed with respect to donor-acceptor-donor approach have low band gap achieved by the coupling of a strong donor with high HOMO level to a strong acceptor with low LUMO level. Thus, the new donor-acceptor material will have a reduced bandgap (Eg) relative to either of its parent components. Due to this point of view, in this study, new electroactive benzothiadiazole and 2,3-bis(4-(tert-butyl)phenyl)quinoxaline monomers substituted with different donor groups (3,4-ethylenedioxythiophene and thiophene) were synthesized to explain the effect of different donor groups on the electronic and optical properties of DAD type polymers. The characterizations of the monomers were performed by 1H and 13C NMR techniques. Electrochemical behavior of both monomers and polymers were studied by cyclic voltammetry. The electrochromic properties of the synthesized conducting polymers were investigated by several methods like spectroelectrochemistry, kinetic and colorimetry studies. The polymers have two different donor units may behave as a copolymer of the symmetric monomer having the same donor groups. Hence, the properties of copolymers were investigated with the co-monomers having either thiophene or 3,4-ethylenedioxythiophene as the donor group.
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Development and studies of electrochromic and electrofluorochromic organic materialsYao, Chengzhang 09 1900 (has links)
Les matériaux électrochromiques organiques ont été un domaine de recherche novateur au cours des dernières décennies. Ces composés qui répondent à un potentiel appliqué par un changement de couleur sont dits électrochromes. Leur intérêt est principalement dû à leur synthèse facile, à haut rendement et à leur aspect écologique par rapport à leurs homologues inorganiques. En règle générale, ces composés ne changent de couleur qu’avec un potentiel appliqué. Développer des composés qui changent à la fois leur couleur et leur fluorescence avec un potentiel appliqué pour une utilisation dans des dispositifs électrofluorescents reste un défi majeur. Dans cette étude, une série de composés contenant de la triphénylamine (TPA) et du benzothiadiazole (BZT) ont été évalués. Ils ont été couplés à différents groupes terminaux pour moduler les propriétés photophysiques et électrochimiques. Ces composés ont été entièrement caractérisés par spectroscopie d'absorption, spectroscopie de fluorescence, voltammétrie cyclique, spectroélectrochimie et diffraction des rayons X. Cela nous a permis d'examiner l'influence de leur structure sur les propriétés. Cela nous a également permis d'identifier les composés d'intérêt idéaux pour une utilisation dans des appareils fonctionnels. Les dispositifs contenant du TPA et du BZT sont idéalement employée pour la fabrication de « fenêtre intelligente ». Cela est dû à l'activité électrochimique du TPA ainsi qu'à la fluorescence à l'état solide du noyau BZT. Pour améliorer encore les propriétés des dispositifs, un système passif était le but ultime. Cela contraste avec les dispositifs actifs où un potentiel doit être appliqué en continu pour que la couleur induite soit cohérente. Dans ce but, des couches cathodiques ont été préparées et étudiées dans un dispositif et leur utilisation comme réservoir d'ions dans un dispositif électrochromique / électrofluorescent passif a été testée. Les résultats préliminaires ont montré que les dérivés d'anthraquinone avaient des propriétés idéales pour les couches cathodiques. / Organic electrochromic materials have been a hot area of research during the past decades. These compounds that respond to an applied potential with a color change are said to be electrochromic. Their interest is mainly because of the easy synthesis, convenient mass production, and eco-friendly preparation compared to their inorganic counterparts. Typically, these compounds change only their color with an applied potential. To develop compounds that change both their color and their fluorescence with a potential applied for use in electrofluorescent devices remains a major challenge. In this study, a series of compounds containing triphenylamine (TPA) and benzothiadiazole (BZT) were evaluated. They were coupled with different end groups to tune the photophysical and electrochemical properties. These compounds were fully characterized by absorption spectroscopy, fluorescence spectroscopy, cyclic voltammetry, spectroelectrochemistry, and X-ray diffraction along with other techniques. This allowed us to examine the influence of their structure on the properties. It also allowed us to identify the ideal compounds of interest for use in functioning devices. The devices containing TPA and BZT are ideally ‘smart window’ applications. This is due to the electrochemical activity by TPA as well as the solid state fluorescence of the BZT core. To further improve the properties of devices, a passive device was the ultimate goal. This is in contrast to active devices where a potential must be applied continuously for the induced color to be consistent. Towards this goal, cathodic layers were prepared and investigated in a device and their use as an ion reservoir in a passive electrochromic / electrofluorescent device was tested. Preliminary results, showed that anthraquinone derivatives had ideal properties for the cathodic layers.
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[en] ALDOL CONDENSATIONS AND CROSS-COUPLING ASSOCIATION AS A STRATEGY FOR OBTAINING PHOTOACTIVE AND BIOACTIVE COMPOUNDS / [pt] ASSOCIAÇÃO DE CONDENSAÇÕES ALDÓLICAS E ACOPLAMENTOS CRUZADOS COMO ESTRATÉGIA PARA A OBTENÇÃO DE COMPOSTOS FOTOATIVOS E BIOATIVOSRAFAELA MARTINS DA COSTA VALEJO 05 September 2022 (has links)
[pt] A partir da associação de condensações aldólicas e acoplamentos cruzados
em blocos de construção arilcarbonílicos já conhecidos, é possível modular as
estruturas conjugadas dos produtos, direcionando-os a diferentes aplicações. Sendo
assim, na presente tese, buscou-se realizar a síntese de todos os compostos por meio
de associações de condensações aldólicas e acoplamentos. Este trabalho está
dividido em quatro capítulos que dizem respeito a: (i) síntese e avaliação fotofísica
de híbridos de chalconas e benzotiadiazolas (BTDs); (ii) síntese e aplicação de
híbridos BTD-chalconas como dispositivos OLEDs; (iii) síntese de chalconas e
BTDs e avaliação de potenciais fotossensibilizadores para DSSCs (células solares
sensibilizadas por corante); (iv) síntese de beta-arilchalconas com potencial atividade
antiestrogênica. Levando em consideração as reconhecidas propriedades fotofísicas
de chalconas e derivados de BTDs, é descrita a síntese de novos híbridos BTDchalcona fotoativos. Os produtos foram obtidos em rotas de duas etapas (reação de
Suzuki e posterior condensação aldólica) com rendimentos reacionais variando
entre 32 e 64 por cento. As modulações nas estruturas foram realizadas de tal forma que os
compostos fossem emissivos no estado agregado. Sabendo das limitações do
desenvolvimento de filmes luminescentes relacionadas ao efeito de quenching
causado por agregação (ACQ), buscou-se sintetizar compostos com propriedades
do tipo AIEE (emissão aumentada induzida por agregação). Os estudos de suas
propriedades fotofísicas demonstraram que o composto com arquitetura arilóxiBTD-chalcona apresentou os melhores resultados nos quais foram observados
aumentos expressivos na intensidade de fluorescência (30x) e no rendimento
quântico de fluorescência (de 0,0070 a 0,143) em estado agregado. Com estes
dados, novos análogos foram sintetizados respeitando o esqueleto do tipo arilóxiBTD-chalcona (ou -fluoreno) com rendimentos que variaram de 42 a 79 por cento. Os
novos análogos também apresentaram AIEE e foram aplicados como camadas
emissoras em OLEDs de estrutura bicamada para avaliação e comparação dos seus
desempenhos eletroluminescentes. A associação de acoplamento cruzado e
condensação aldólica também foi utilizada como estratégia para a produção de
novos fotossensibilizadores para DSSCs. Para tal, buscou-se sintetizar compostos
do tipo D-pi-A-pi-A, nos quais os grupos aceptores terminais têm a função de
ancoradores de TiO2. O uso deste tipo de estrutura facilita a injeção de elétrons
devido à transferência direcional de elétrons do doador para a porção aceptora. Com
base nisso, foram sintetizados novos derivados de chalconas e BTDs. As sínteses
foram realizadas em duas etapas resultado em rendimentos de 35 a 44 por cento. Estudos
eletroquímicos apontaram bons valores de HOMO, LUMO e band gap para todos
os compostos. Os valores de LUMO se mostraram acima da faixa de condução do
semicondutor TiO2 (-4,0 eV), garantindo a força motriz necessária para o
direcionamento dos elétrons. Além disso, os valores de HOMO de todos os
compostos se mostraram inferiores ao potencial redox do eletrólito (-4,8 eV)
gerando uma alta força motriz para regeneração do corante. Por meio de
Espectrometria de UV-Vis, foi observado que os compostos absorvem em região
próxima a 350 nm em diferentes solventes, o que dificulta o uso destes como
DSSCs. Por fim, no último capítulo foi apresentada uma nova estratégia para a
obtenção de moléculas potencialmente bioativas a partir da associação entre
condensações aldólicas e reações de acoplamento. O sistema alfa-beta insaturado da
chalcona torna essa uma interessante plataforma para inserção régio- e
estereosseletiva de substituintes arílicos na porção olefínica do substrato. A partir
de uma estratégia de inserção de porções arílicas já descrita por nosso grupo,
aplicamos estas para a síntese de análogos do tamoxifeno, fármaco utilizado
atualmente no tratamento de alguns tumores de mama. Seis produtos foram
sintetizados por meio de uma reação de Heck, resultando em misturas E/Z de
aproximadamente 50:50 e rendimentos de 29 a 57 por cento. / [en] It is possible to modulate the conjugated structures of the products, directing
them to different applications from the association of aldol condensations and crosscouplings in known arylcarbonyl building blocks,. In this sense, this thesis is
divided into four chapters concerning: (i) synthesis of analogues and hybrids of
chalcones and BTDs; (ii) synthesis and application of chalcone-BTD hybrids as
OLED devices; (iii) synthesis and evaluation of potential photosensitizers for
DSSCs (dye-sensitized solar cells); (iv) synthesis of compounds with potential
antiestrogenic activity. For the synthesis of all compounds, associations of aldol
condensations and cross couplings were performed. Considering the recognized
photophysical properties of chalcones and BTD derivatives, the synthesis of new
photoactive BTD-chalcone hybrids is described. The products were obtained in
two-step routes (Suzuki reaction and aldol condensation) and reaction yields ranged
from 32 to 64 percent. The modulations in the structures were performed in such a way
that the compounds were emissive in the aggregated state. Knowing the limitations
of the development of luminescent films related to the aggregation-caused
quenching effect(ACQ), compounds were synthesized with AIEE-like properties
(aggregation-induced increased emission). The studies of its photophysical and
electrochemical properties indicated that a compound with aryloxy-BTD-chalcone
architecture presented the best results in which expressive increases were observed
in fluorescence intensity (30x) and in fluorescence quantum yield (from 0.0070 to
0.143) with the aggregation. With these data, new analogs were synthesized
respecting the aryloxy-BTD-chalcone (or -fluorene) with yields ranging from 42 to
79 percent. The new analogues also presented AIEE and were applied as emitting layers
in bilayer structure OLEDs for evaluation and comparison of their electroluminescent performance. The association of cross-coupling and aldol
condensation was also used as a strategy to produce new photosensitizers for
DSSCs. To this end, D-pi-A-pi-A compounds were synthesized in which the terminal
acceptor groups act as TiO2 anchors. The use of this type of structure facilitates the
injection of electrons due to the directional transfer of electrons from the donor to
the acceptor portion. Based on this, new derivatives of chalcones and BTDs were
synthesized. The syntheses were performed in two steps resulting in yields of 35 to
44 percent. Electrochemical studies showed good HOMO, LUMO and band gap values
for all compounds. The LUMO values were above the TiO2 semiconductor
conduction range (-4.0 eV) which guarantees the necessary driving force for the
directioning of electrons. In addition, the HOMO values of all compounds were
lower than the redox potential of the electrolyte (-4.8 eV) generating a high driving
force for dye regeneration. It was observed that the compounds absorb in a region
close to 350 nm in different solvents, which makes their use as DSSCs difficult.
Finally, in the last chapter, a new strategy was presented to obtain potentially
bioactive molecules from the association between aldol condensations and coupling
reactions. The alpha-beta unsaturated system of chalcone makes it an interesting platform
for regio and stereoselective insertion of aryl substituents in the olefinic portion of
the substrate. Based on a strategy of insertion of aryl moieties already described by
our group, tamoxifen, a drug currently used in therapy for the treatment of some
breast tumors, analogues were synthesized. Six products were synthesized via a
Heck reaction, resulting in E/Z mixtures of approximately 50:50 and yields of 29 to
57 percent.
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[en] ARYLOXY-SUBSTITUTED BENZOTHIADIAZOLE DERIVATIVES: A NEW CLASS OF ORGANIC EMITTERS FOR OLEDS / [pt] DERIVADOS DE BENZOTIADIAZOLA ARILÓXISUBSTITUÍDOS: UMA NOVA CLASSE DE EMISSORES ORGÂNICOS PARA OLEDSALESSANDRA PAZINI 07 October 2019 (has links)
[pt] O planejamento racional e a obtenção de novos compostos luminescentes com aplicações específicas continua sendo um importante desafio em síntese orgânica. Derivados do núcleo benzotiadiazola (BTD) com conjugação (Pi) estendida têm sido amplamente sintetizados e aplicados em diferentes aspectos da
tecnologia da luz. Em geral, na estrutura desses derivados, grupos doadores de elétrons (D) são ligados ao anel BTD, que tem caráter aceptor de elétrons (A). Até o presente momento não haviam sido descritos derivados de BTD cuja porção doadora é um grupamento arilóxi. No presente trabalho foi desenvolvida uma rota sintética para derivados de BTD arilóxi-substituídos. Os compostos se mostraram altamente luminescentes em solução (Rendimento quântico de fluorescência de até 74 por cento) e com band gap adequado para aplicação em camadas emissoras de OLEDs. O desenvolvimento/otimização dos compostos foi dividido em duas partes. Na primeira parte, foram determinadas as condições reacionais para a obtenção dos novos derivados e foi avaliada qual a melhor configuração dos compostos: arilóxi-BTD aceptor ou arilóxi-BTD-doador. Um composto com característica arilóxi-BTD-doador se mostrou mais emissivo, assim, construiu-se um dispositivo OLED verde utilizando-o como camada emissora, como uma prova de conceito. Na segunda parte do trabalho, foi realizada uma otimização estrutural mais abrangente, onde oito novos derivados foram sintetizados e caracterizados. Através dessa nova otimização chegou-se no composto líder 4-(4-metoxifenóxi)-7-o-toluilbenzo[c][1,2,5]tiadiazol, que apresentou band gap eletroquímico de 3,2 eV, máximo de emissão em 471 nm (azul), emissão induzida por agregação e 83 por cento de rendimento quântico de fluorescência no estado sólido. A partir desse emissor puramente orgânico otimizado serão construídos novos dispositivos OLED. / [en] The rational planning and obtention of new luminescent compounds with specific applications can be considered an important challenge in organic synthesis. Benzothiadiazole (BTD) derivatives with extended (Pi) conjugation have been widely synthesized and applied in different aspects of light technology. In general, in the structure of these derivatives, electron donor groups (D) are bound to the BTD ring, which has electron acceptor character (A). To date, BTD derivatives in which the donor moiety is an aryloxy group have not been described. In the present work a synthetic route for aryloxy-substituted BTD derivatives has
been developed. The compounds are highly luminescent in solution (Quantum fluorescence yield up to 74 percent) and display suitable band gaps for application as emitting layers in OLEDs. The development/optimization of the compounds was divided into two parts. In the first part, the reaction conditions were optimized and the best architecture of the compounds was evaluated: aryloxy-BTD-acceptor or aryloxy-BTD-donor. A compound with aryloxy-BTD-donor design displayed more intense emission, thus, a green OLED device was constructed using it as a emitting layer, as a proof of concept. In the second part of the work, a more comprehensive structural optimization was performed, and eight novel derivatives were synthesized and characterized. By means of this new optimization, the lead compound 4-(4- methoxyphenoxy)-7-o-tolylbenzo[c][1,2,5]thiadiazole was obtained, which showed an emission maximum at 471 nm (blue), band gap of 3,2 eV, aggregation emissioninduced and 83 percent of photoluminescence quantum yield in the solid state. This new leader compound will be explored as emissive layer in novel OLED devices.
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Design de polymères conjugués pour des applications dans le photovoltaïque assisté par modélisation moléculaire / Design of π-conjugated polymers for photovoltaic applications assisted by theoretical modellingFradon, Alexis 30 November 2016 (has links)
Ces dernières années, un nouveau type de polymère donneur d’électron pour des applications photovoltaïques a été étudié de manière intensive, les copolymères à faible bande interdite. Ils sont constitués d’un groupement riche en électron (ER) et d’un groupement pauvre (EP) permettant de contrôler les orbitales frontières et d’induire une délocalisation de l’exciton généré lors du processus de photo-excitation. Une large variété de dispositifs est basée sur ces copolymères avec des rendements d’environ 10% et, pour accroitre leur efficacité, il est nécessaire d’avoir une meilleure compréhension de ces polymères pendant le phénomène de photo-absorption. La chimie théorique apparait comme un outil permettant de prédire différentes propriétés optoélectroniques. Au cours de ce travail, nous avons utilisé la théorie de la fonctionnelle de la densité indépendante (DFT) et dépendante du temps (TD DFT) pour simuler les propriétés optiques d’oligomères de taille croissante avec différents groupements ER et EP. Les propriétés optiques des polymères correspondant ont été extrapolées à l’aide du modèle de Kuhn. Ce criblage théorique nous a permis de sélectionner des systèmes prometteurs à base de benzodithiophène, de benzothiadiazole et de benzofurazane qui ont ensuite été synthétisés par couplage de Stille. Les polymères et oligomères obtenus ont été caractérisés par spectroscopie UV-visible et de fluorescence, chromatographie d’exclusion stérique et par RMN dans le but d’observer des relations structure-propriétés et de faire des corrélations entre résultats expérimentaux et théoriques. / During the last decade, a new kind of donor polymers for photovoltaic application have been intensively studied, the low band-gap polymers. They are based on repeating units associating two different moieties, one electron-rich (ER) and one electron-poor (EP), which allow to finely tune the molecular orbitals and to induce a delocalization of the exciton generated upon the photo-excitation process. A large variety of devices are based on such low band-gap polymers, with a power conversion efficiency record around 10%, and, to increase the efficiency, it is necessary to have a better understanding of these polymers during the photo-absorption phenomenon. Computational chemistry isa powerful tool that permits to predict different opto-electronic properties. For this work, we used Density Functional Theory and Time-Dependent Density Functional Theory to compute the optical properties of increasingly large oligomers involving various ER and EP subunits. The optical properties in the polymer limit were then estimated for the different systems by using an extrapolation scheme based on the Kuhn equation. This theoretical screening allowed us to select promising candidates based on benzodithiophene, benzothiadiazole and benzofurazan for syntheses, which were performed by a Stille coupling. The obtained polymers and size-controlled oligomers were further characterized by UV visible spectroscopy, fluorescence, size exclusion chromatography and NMR, in order to extractstructure-properties relationships and correlate experimental results to theoretical data.
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Electropolymerization and electrochromism of poly(4,7-dithien-2-yl-2,1,3-benzothiadiazole) and its copolymer with 3-methoxythiophene in ionic liquidsTsegaye, Abebaw Adgo January 2013 (has links)
Philosophiae Doctor - PhD / This thesis is based on the study of electropolymerization and electrochromism of poly(4,7- dithien-2-yl-2,1,3-benzothiadiazole) (P(DTBT) and its copolymer with 3-methoxythiophene (MOT) in imidazolium ionic liquids (ILs) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimbf4) hydrophilic, 1-butyl-3-methylimidazolium hexafluorophosphate (bmimpf6) and 1- butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (bmimtnf2) hydrophobic ILs. Traditional organic solvents acetonitrile and dichloromethane in the presence of 0.1 M tetrabutylammonium perchlorate (n-Bu4NClO4) as a supportive electrolyte was also used as a medium for comparison. Besides, a more hydrophobic ionic liquid, 1-octyl-3- methylimidazolium bis(trifluoromethylsulfonyl)imide (octmimtnf2) was also used for the electrodeposition of poly(3-methoxythiophene) (PMOT). The techniques employed are cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), uv-visible spectroelectrochemistry and scanning electron microscopy (SEM). 4,7-Dithien-2-yl-2,1,3-benzothiadiazole (DTBT) a type of donor –acceptor monomer and 3- methoxythiophene (MOT) has been electropolymerized using ionic liquids as growth and supportive electrolytes.
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Color Engineering OfIcli Ozkut, Merve 01 August 2011 (has links) (PDF)
Design of a monomer is a viable route for adjusting the properties of its corresponding polymer. The main goal of this study is to design and synthesize novel soluble polymers having various colors of color palette and amenable for use in electrochromic device applications. In designing the monomers, the factors affecting the properties of the polymers are also considered. For this purpose, each part of the monomers is chosen properly for each desirable properties and the effect of them is investigated separetely. Thus, this study is based on the investigation of the effect of three major parts on the polymer properties: Donor groups, acceptor groups and the length of alkyl chain. For this aim, nine D-A-D type monomers, TSeT, ESeE, PSeP-C10, PSP-C10, PNP-C10, POP-C10, PSeP-C4, PSP-C4 and PSP-C6, and their corresponding polymers, P(TSeT), P(ESeE), P(PSeP-C10), P(PSP-C10), P(PNP-C10), P(POP-C10), P(PSeP-C4), P(PSP-C4) and P(PSP-C6), based on thiophene, 3,4-ethylenedioxythiophene (EDOT), and 3,3-dialkyl-3,4-dihydro-2H-thieno[3,4-b]-[1,4]dioxepine (ProDOT-Cn) as D units and 2,1,3-benzoselenadiazole, 2,1,3-benzothiadiazole, 2-decyl-2H-benzo[d][1,2,3]triazole, and 2,1,3-benzooxadiazole as A units were synthesized. The obtained polymers have somewhat low band gap between 1.13 eV and 1.80 eV, they show electrochromic behaviors. Among them P(POP-C10), P(PSP-C10) and P(PSP-C6) have cyan color which is one leg of CMY (Cyan-Magenta-Yellow) color spaces. Since there have been scant studies on cyan colored polymers in the literature, these polymers are so precious. Via copolymerization of PNP-C10 and PSeP-C10, the first electrochemically synthesized neutral state black polymer was obtained.
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