A aplicação de nanotubos de carbono em nanotecnologia está condicionada ao controle das propriedades eletrônicas e geométricas das amostras. Recentemente, tem crescido o uso de polímeros conjugados para suspender seletivamente nanotubos semicondutores com uma distribuição estreita de diâmetro. Em 2007, Adrian Nish e colaboradores mostraram que o polímero conjugado poli[9,9-dioctilWuorenil-2,7-diil] (PFO) suspende seletivamente nanotubos semicondutores de cerca de 1,0nm de diâmetro e ângulo quiral próximo de 25. Em seguida, o grupo de Maria Antonietta Loi foi capaz de medir a Wuorescência do PFO envolvido em nanotubos, medindo pela primeira vez as propriedades ópticas de um polímero ao interagir com os nanotubos. Mais recentemente, diversos grupos conseguiram suspender nanotubos semicondutores com diâmetros maiores que 1,0 nm através do enovelamento de polímeros conjugados. Diferentes cadeias principais apresentaram resultados, como homopolímeros derivados dos Wuorenos e tiofenos e copolímeros em que unidades Wuoreno foram combinadas com piridinas, antracenos e outros compostos aromáticos. A natureza da cadeia principal parece ter um papel na seletividade de quiralidades especíVcas. Entretanto, a solubilização de nanotubos de grandes diâmetros com frequência utiliza polímeros com cadeias laterais alquiladas com pelo menos 12 carbonos. Neste trabalho, desenvolvemos um método para simular o espectro de emissão de uma molécula em condições dinâmicas a Vm de capturar a variedade de conformações acessíveis à molécula interagindo com o ambiente. Isso nos permitiu obter um espectro de emissão mais realista. Aplicamos esse método no sistema PFO + nanotubos e observamos, juntamente com uma análise das energias de interação, que o polímero se encontra enrolado em hélice ao redor do tubo e que a interação entre as cadeias laterais rege o o comportamento do polímero. Buscamos compreender o mecanismo de seletividade e suspensão de nanotubos de maior diâmetro através de dinâmica e mecânica molecular. Observamos, com o uso de simulações de dinâmica de impulso, que a eVciência do recobrimento da superfície do tubo pelo polímero está associada à relação entre a circunferência do tubo e o comprimento da cadeia lateral. Tubos de diâmetro incompatível com os radicais acabam por ter suas paredes expostas ao solvente e, consequentemente, ao reagrupamento com outros nanotubos. Finalmente, propusemos um modelo granulado que permitiria obter informações sobre a interação entre os polímeros e os nanotubos em uma escala temporal maior, da ordem de s. Relatamos aqui os resultados parciais dos testes deste modelo e a rota para seu futuro desenvolvimento. / The eUective use of carbon nanotubes in nanotechnology depends on the Vne tuning of electronic and geometric properties of the samples. Recently, the use of conjugated polymers to selectively suspend semiconducting nanotubes of a narrow diameter distribution has received attention in the literature. In 2007, Andrian Nish and collaborators showed that the conjugated polymer poly[9,9- dioctylWuorenyl-2,7-diyl] (PFO) selectively suspends nanotubes with diameter of the order of 1.0nm and chiral angles close to 25. Subsequently, Maria Antonietta Lois group was able to measure the Wuorescence of PFO chains wrapped around nanotubes, hence for the Vrst time measuring the optical properties of a polymer interacting with nanotubes. More recently, various groups reported the successful suspension of semiconducting nanotubes with diameters larger than 1.0nm by wrapping with conjugated polymers. DiUerent polymer backbones showed positive results, such as homopolymers based on Wuorene and thiophene and copolymers based on Wuorene units combined with pyridines, anthracenes and other aromatic compounds. The backbone structure seems to have an eUect on the chirality selectivity. On the other hand, the solubilization of large-diameter nanotubes frequently involves polymers having alkyl sidechains with at least 12 carbon atoms. In this work, we developed a method to simulate the emission spectrum of a molecule in dynamic conditions in order to capture the variety of accessible conformations of the molecule interacting with the environment. This allowed us to obtain a more realistic emission spectrum. We applied this method to the PFO + nanotube system and observed, in association with binding energy analysis, that the polymer wraps around the nanotube in an helical conformation and that the sidechain interaction governs the polymer behavior. We were able to understand the selectivity mechanism for large-diameter tubes through molecular mechanics and molecular dynamics simulations. We observed, using impulse dynamics simulations, that the nanotube surface coverage eXciency depends on the relation between the nanotube circumference and the sidechain length. Tubes whose diameter is incompatible with the sidechain length present wall regions that are exposed to the solvent, therefore exposed to rebundling with other tubes. Lastly, we proposed a coarse-grained model that could provide information about the long-term behavior of the NT + PFO complexes, in the s range. Here we report partial test results for this model and outline the route for future developments.

Esta tese de doutorado é resultado do estudo da fotocondutividade em materiais poliméricos, com particular enfoque em diodos poliméricos com camada ativa de derivados do poli (p-fenileno vinileno) (PPV): OC10-PPV, SY e MEH-PPV, em estrutura tipo sanduíche (ITO/polimérico/Metal) de camada única, utilizando eletrodos metálicos com diferentes funções trabalho depositados sobre o mesmo filme. Para isso, foi necessária a realização de todas as etapas de fabricação de dispositivos orgânicos, como descritas neste trabalho, para obter resultados com o máximo de reprodutibilidade, bem como o domínio das técnicas de caracterização. As propriedades ópticas dos filmes poliméricos foram analisadas através dos espetros de absorção e de fluorescência estacionária na região do visível. O comportamento fotocondutivo dos dispositivos foi realizado através de medidas de corrente-tensão (I-V) e da espectroscopia de fotocorrente no estado estacionário em regime dc sob incidência de luz com diferentes comprimentos de onda, ora através do ITO, ora através dos eletrodos metálicos semitransparente, para o dispositivo sob diferentes valores de tensões aplicadas. A variação desses parâmetros permitiu verificar como estes influenciam na fotogeração e no transporte de portadores de cargas e assim adaptar e aplicar um modelo teórico que levasse em consideração o campo elétrico aplicado para ajustar a fotocorrente obtida experimentalmente, obtendo informações sobre as propriedades de fotocondutividade dos materiais estudos. / This thesis is a study about photoconductivity in polymeric materials, in particular diodes with single-layer sandwich structure derivates of poly(para-phenylene vinylene) (PPV): OC10-PPV, SY and MEH-PPV. Different metallic electrodes were deposited on the same polymeric layer. Therefore, it was necessary to realize the devices fabrication process step by step as well to dominate the characterization techniques. The optical properties of polymeric film were analyzed through the absorption and emission spectrum in the visible region. The photoconductivity behavior was studied by dc current-voltage (I-V) and photocurrent action spectra through the absorption and emission spectrum in the visible region. The photoconductivity behavior was studied by dc current-voltage (I-V) and photocurrent action spectra through the both side of device under applied voltages. The variation of these parameters allowed verifying how are influencing in the charge carrier photo-generation and the charge transport and then to adapt and apply a theoretical model wich considers the electric field applied to fit the photocurrent action spectra of devices. The values of the parameters allow to survey important about photoconductivity properties of the materials

Recentemente tem sido observado grande avanço na área de fotovoltaicos orgânicos e híbridos. Esses dispositivos baseiam-se em diferenças de energia eletrônica nas interfaces dos componentes de uma heterojunção, onde as heterojunções dispersas obtidas via arranjos interpenetrantes com estes dois compostos, em dimensões sub-20-nm, permite coleção efetiva dos portadores de carga fotogerados, mesmo com pequeno comprimento de difusão do éxciton e baixa mobilidade dos portadores de carga. Desta maneira, o estudo e a modificação da interface entre as duas fases é essencial para melhorar a eficiência de conversão desses dispositivos. Este trabalho tem como objetivo investigar heterojunções de dióxido de titânio (TiO2)/poli(3-hexil tiofeno) (P3HT) como camadas ativas em dispositivos fotovoltaicos híbridos. Essas heterojunções são atraentes para fotovoltaicos híbridos por permitir a nanoestruturação do metalóxido antes da incorporação do polímero, levando à obtenção de elevada área interfacial e com a possibilidade de ajustar as propriedades interfaciais mantendo o caráter aceitador/doador desta heterojunção. Os filmes de TiO2 foram obtidos a partir de dispersões coloidais de nanopartículas de anatase, enquanto aqueles de P3HT foram obtidos a partir de sua solução de 1,2-diclorobenzeno. Como eletrodos foram utilizados o óxido de índio dopado com óxido de estanho (ITO) e ouro (Au). A caracterização elétrica e espectroscópica indicou que os parâmetros fotovoltaicos, bem como absorção e fotoluminescência, dependem da submissão dos dispositivos a tratamentos térmicos post-production, evidenciando que o aquecimento induz a mudanças conformacionais no polímero, alterando a interface óxido/polímero. A introdução de grupos carboxilato nas ramificações 3-hexil do P3HT permite melhor contato entre óxido/polímero, sendo favorecido por tratamento térmico. Mais ainda, a infiltração do polímero em filmes de TiO2 nanocristalino levou à obtenção de dispositivos fotovoltaicos de considerável estabilidade, apresentando atividade mesmo após 6 meses após a elaboração destes. Finalmente, neste trabalho também é proposta a utilização de um complexo a base de ftalocianina de zinco como modificador de interface do TiO2, cuja absorção estende a janela espectral do dispositivo até o vermelho e infravermelho próximo. Estudos de fenômenos de transporte, levando-se em conta a fotogeração de portadores e sua recombinação, foram realizados por medidas do espectro de fotocondução no dispositivo / Recently a fast development in organic and hybrid photovoltaic field has been observed. Such devices are fabricated by organic semiconductors within components of a heterojunction, in which bulk heterojunctions obtained via interpenetrating networks at the sub-20-nm length scale. It permits the effective collection of photogenerated charge carriers even with low exciton diffusion length and low charge carrier mobilities. Therefore, the study of material properties and the interface modification are essential to improve the power efficiency of such devices. The goal of this work is to investigate heterojunctions of titanium dioxide (TiO2) and poly(3-hexyl thiophene) (P3HT) as active layers in hybrid photovoltaic devices. Such heterojunctions are attractive since the metaloxide can be nanostructured previous the infiltration of the polymer within the nanocrystalline phase, leading on large interfacial area with the possibility to tune the interfacial properties keeping the acceptor/donor character of the two components. Titania films were obtained from colloidal dispersions of anatase nanoparticles, while P3HT from its solution in 1,2-dichlorobenzene. The electrodes were indium-tin oxide (ITO) and gold (Au). Electrical and spectroscopic characterization shows the photovoltaic parameters, as well as absorption and photoluminescence, depends on post-production treatments, evidencing that heating induces conformational changes in the polymeric phase, changing the oxide/polymer interface. The introduction of carboxyl groups at 3-hexyl ramifications in P3HT permits better contacts between oxide and polymer by chemisorption, being favored by thermal treatment. Furthermore, the infiltration of the polymer within the nanocrystalline TiO2 leads on enhanced stability of the devices, working even six months after their preparation. Finally, in this work is also proposed the utilization of a interface modifier based on zinc phtalocyanine complex, which has extended the device absorption window up to the red/ near infrared, increasing light harvesting, and a transport study related to photocarriers generation and recombination process was carried out by photoconductivity action spectra

Nesta dissertação, visamos o entendimento de processos intermediários que regem a transferência de energia e determinam as propriedades ópticas de polímeros conjugados, a fim de encontrar meios para aumentar a eficiência de emissão e o tempo de vida dos ?LED?s? orgânicos. Estudamos especificamente o polímero PPV, poli(p-fenileno vinilideno), sintetizado através de novo método desenvolvido no Grupo de Polímeros do Instituto de Física de São Carlos, por Marletta e colaboradores[1], na forma de filmes finos depositados pelas técnicas ?spincast? e de automontagem (LbL). Para o trabalho utilizamos técnicas espectroscópicas de luminescência, excitação seletiva e absorbância. Por meio de técnicas de engenharia molecular e através do ordenamento induzido da rede polimérica, avaliamos o peso que têm os eventos intermediários à emissão. Estiramos gradualmente filmes de PTHT/PPV depositados sobre Teflon, sob um eixo preferencial, e constatamos a dependência da polarização da luz emitida com processos de transferência de energia e com a anisotropia da matriz polimérica. Realizamos a separação das cadeias do copolímero a fim de analisar separadamente a transferência de energia entre os segmentos conjugados pertencentes a cadeias distintas (processos intercadeia) ou ao longo da cadeia (processos intracadeia). Esta separação intercadeia e intracadeia resultaram em um significativo aumento da eficiência da emissão, assim como um deslocamento da banda de emissão para o azul, privilegiando a emissão de segmentos de menor conjugação e que participavam apenas nos processos de relaxação de energia e transferência da excitação e não dos estados emissivos finais. Separamos os segmentos conjugados dentro da própria cadeia do copolímero, regulando o comprimento de conjugação, através da incorporação de DBS. Aqui, verificamos, os processos de transferência intracadeia concorrem em igual peso com processos intracadeia na migração energética em polímeros conjugados. Concluímos que o processo limitante da eficiência de emissão em polímeros conjugados e dispositivos é a eficiente transferência de energia entre cadeias ou ao longo da cadeia para centros supressores de energia. / The main goal of this work is the understanding of intermediated energy relaxation processes that are governed by Energy Transfer. Such processes strongly affect the optical properties of conjugated polymers, reducing the emission efficiency and the life time of OLEDs. We study specifically the polymer poly(p-phenylene vinylene), PPV, synthesized through the new method developed by Marletta and co-workers [1]. The films were prepared by Spincast and self-assembly (Layer-by-Layer) techniques on different substrates. The optical characterization of the polymeric material was carried out by photoluminescence, selective excitation spectroscopy and UV-Vis absorbance measurements. With the use of molecular engineering techniques and by changing the polymeric order induced by uniaxial stretch of the films deposited on a flexible substrate, it was possible to infer the weight of intermediary events in final emission process. A special issue of this work was the study of the optical properties of thin PPV films deposited on flexible Teflon substrates under very low deformation levels. Optical data of low stretched conjugated polymers on transparent substrates were not previously available in the literature. Continuous axial stretch was applied at room temperature to very thin PPV films enabling simultaneous luminescence and absorbance polarization measurements. The optical properties of polymeric light emitting devices are strongly dependent on the structural order of the polymer chains and the energy transport mechanism between the conjugated segments. We demonstrate that such low stretched films presents a very efficient isotropic-to-polarized conversion regarding the fact we are dealing with energy transfer between luminescent chromophore of same species. We also carried out chain separation of conjugated segments of a PPV copolymer in order to analyze two Energy Transfer kinds: one that occurs among PPV segments in different chains (interchain processes) and the other involving the Energy Transfer between PPV segments along the same PPV chain (intrachain processes). To account for the interchain separation of the PPV segments we diluted the PPV chain in an inert polymeric matrix. The novelty, however, lies in the precise control of the separation of PPV segments along the chain by using a copolymer with sequences of conjugated PPV and non-conjugated PTHT distributed randomly along the polymer chain. The efficiency increase together with the spectral blue shif with the segment separation show that inter- and intrachain exciton mobility is enhanced by low range Förster Energy Transfer. For the case of samples without chain separation, it is easier for excitons to move around by energy transfer process and find quenching defects before their radioactive decay. For diluted or low conjugated samples, excitons will not reach defects before recombination since Energy Transfer is suppressed. Thus, we verify, the Intrachain Energy Transfer process have the same influence as for Interchain process produced by the energy migration among conjugated polymers segments. From a more fundamental point of view, the establishment of a controlled ordering and separation of the polymeric chains may reduce effects such as the luminescence quenching that strongly reduce the emission efficiency in organic devices.

Existem algumas técnicas destinadas ao estudo das características fotofísicas de materiais orgânicos ou dispositivos eletrônicos e optoeletrônicos a base de semicondutores orgânicos. A exemplo disso, a técnica de espectroscopia de absorção fotoinduzida de onda contínua (Continuous Wave Photoinduced Absorption/cw-PIA) apresenta grande sensibilidade como método destinado ao estudo dos processos eletrônicos envolvendo espécies excitadas de vida longa. Esta técnica emprega dois feixes ópticos distintos, um para excitação da amostra e outro (feixe de prova) para investigar os estados excitados remanescentes em amostra após bombeio óptico. O presente trabalho tem como objetivo a construção, desenvolvimento e caracterização de um aparato experimental para espectroscopia cw-PIA. A montagem bem sucedida da técnica foi testada em filme do polímero semicondutor P3HT, em filme de blenda (1:1) de P3HT/PCBM (comumente utilizada como camada ativa em células solares orgânicas) e em filmes automontados camada-a-camada (LbL) do tipo doador-aceitador de carga (P3KHT/P6N), sendo que a molécula P6N foi sintetizada pelo Grupo de Polímeros Bernhard Gross do IFSC-USP. Os filmes LbL de P3KHT/P6N, em comparação aos filmes blenda de P3HT/PCBM, demonstraram uma eficiência maior quanto a geração de portadores de carga com tempo de vida longo. / There are some techniques for the study of photophysical characteristics of organic materials or electronic and optoelectronic devices based on organic semiconductors. For example, the technique of continuous wave photoinduced absorption spectroscopy (cw-PIA) is a highly sensitive method for the study of the electronic processes involving long-lived excited species. This technique uses two distinct optical beams, one for sample excitation and another for probing the excited states remaining in the sample after optical pumping. The present work aims at the construction, development and characterization of an experimental apparatus for cw-PIA spectroscopy. The successful implementation of the technique was tested in a film of the semiconducting polymer P3HT and of the blend (1:1) P3HT/ PCBM (usually employed as active layer in organic solar cells), and also in a Layer-by-Layer (LbL) film of donor-acceptor molecules P3KHT/P6N, where the P6N molecule has been synthesized by Polymer Group Bernhard Gross at IFSC- USP. The comparison between P3KHT / P6N LbL film and the blend P3HT/PCBM has demonstrated higher charge carrier generation efficiency (with long lifetime) for the LbL film.

Le sujet de cette thèse se situe dans le contexte de l'électronique organique à base de polymères conjugués et de nanotubes de carbone. Nous avons choisi la famille des polyfluorènes principalement en raison de leur émission dans le bleu, leur bon rendement quantique ainsi que pour la facilité avec laquelle on peut modifier leurs propriétés en greffant différents groupements fonctionnels sur la structure de base du fluorène. L'originalité des recherches effectuées au laboratoire concerne la structure des films électroluminescents que nous réalisons. Leur principe de fonctionnement repose sur l'utilisation de nanotubes de carbone en tant que film support pour le dépôt du polymère. Le travail réalisé au cours de cette thèse a principalement consisté à élaborer des films de polymères avec des épaisseurs et des taux de dopage contrôlés à la surface des nanotubes de carbone en optimisant les divers paramètres de synthèse électrochimique. Nous avons également utilisé des groupements fonctionnels pour améliorer les performances du polyfluorène et augmenter la compatibilité entre les couches polymère/nanotubes de carbone. Dans cette optique, nous avons mis en œuvre l'utilisation de différents outils pour la caractérisation des propriétés des films. Les propriétés intrinsèques des nanotubes de carbone ont donc pour effet de doper le polymère et d'améliorer le transport des charges au sein des couches tout en maintenant les performances de luminescence dans le bleu des polyfluorènes. / The subject of this thesis lies in the context of organic electronic based on conjugated polymers. We have chosen the class of polyfluorene mainly because of their blue emission, good quantum efficiency and possibility of modifying their properties by grafting side chain groups. The originality of our research relies upon the use of a particular devices structure. The structure of our electroluminescent films is based on the use of a thin layer of carbon nanotubes added to the structure of the emissive layer without involving any chemical modification.The work done in this thesis has mainly consisted of deposing polymer films with thicknesses and doping level controlled on the surface of carbon nanotubes by optimizing various parameters of the electrochemical synthesis. Functional groups have also been grafted on the side of chains in order to improve the performances of the polymer and to increase the compatibility between the polymer layer and the carbon nanotube dispersion. The use of carbon nanotubes should improve the charge carriers whitout quenching the photophysical properties of the polymers.

As key components of flexible organic electronics, the synthesis of polythiophenes via less toxic and more cost-effective routes is demanded. An efficient synthetic route for the production of thienyl-containing homopolymers and copolymers has been developed. The synthetic approach consists of: i) the synthesis in high yield and high purity of thienyl borane monomers protected with N-methyliminodiacetic acid (MIDA) via C-H electrophilic borylation. This reaction uses a combination of inexpensive reagents BCl3, AlCl3, and 2,6-dichloropyridine (Cl2Py) for the regioselective electrophilic aromatic substitution of thiophenes, followed by addition of a second aprotic amine pre-esterification to reduce the Brønsted acidity of the reaction mixture. In situ esterification provided the desired thienyl MIDA boronateester monomers in one-pot at room temperature. ii) Subsequent Suzuki-Miyaura polymerisation of the synthesised monomers to produce well defined thienyl containing pie-conjugated polymers in high molecular weight and high yields. Key reaction parameters for successful Suzuki-Miyaura polymerisation of thienyl-derived MIDA boronate esters under mild temperatures (i.e., 55 °C in THF) were found: a) an optimal monomer:H2O:base ratio, which enables controlled hydrolysis of the BMIDA moiety into its corresponding boronic acid at appropriate rates for high fidelity polymerisation. b) Nature of the base, where K3PO4 provided the best results for production of homopolymers (e.g., rr-P3HT), or KOH which gave excellent results for the formation of copolymers across a range of electronically different comonomers (e.g., pCPDT-BT). Thus, it is demonstrated that the approach is a general strategy for the highly efficient production of thienyl containing pie-conjugated regioregular, regiosymmetric and Donor-Acceptor polymers.

<p>During the last 30 years a new research and technology field of organic electronic materials has grown thanks to a groundbreaking discovery made during the late 70’s. This new field is today a worldwide research effort focusing on exploring this new class of materials that also enable many new areas of electronics applications. In the organic electronics research field conducting organic molecules and polymers are synthesized and used in devices. The reason behind the success of conducting polymers is the flexibility to develop materials with new functionalities via clever chemical design and the possibility to use low-cost production techniques to manufacture devices.</p><p>This thesis reviews and describes different aspects of the organic electronics, here focusing on electrochromic displays; device improvements, the study of degradation and also patterning technology for rational manufacturing processing. The color contrast in electrochromic displays based on conjugated polymers was increased with approximately a factor of two by adding an extra electrochromic polymer. It was found that electrochemical over-oxidation (ECO) limits the flexibility in choosing desired electrochromic materials. ECO is one of the main degradation mechanisms in electrochromic displays. ECO is an efficient and fast process to permanently reduce the electronic conductivity in polythiophenes. From this, a novel patterning process was developed, in which the films of polythiophenes can be patterned through local and controlled deactivation of the conductivity. The ECO has been combined with different patterning tools to enable the use of existing printing tools for manufacturing. In combination with screen-printing, low-cost and high volume roll-to-roll patterning was demonstrated, while together with photolithography, patterning down to 2 µm can be achieved. Systematic studies have shown that conductivity contrasts beyond 107 can be achieved, which is enough for various simple electronic systems. To generate better understanding of the ECO phenomena the effect of pH on the over-oxidation characteristics was studied. The results suggest that a part of the mechanism for over-oxidation depends on the OH– concentration of the electrolyte used.</p>

The research field of conjugated polymers has grown due to the optical and electronic properties of the material, useful in applications such as solar cells and printed electronics, but also in biosensors and for interactions with biomolecules. In this thesis conjugated polymers have been used in two related topics; to detect conformational changes in proteins and to assemble the polymers with biomolecules into nanowires. Within biosensing, conjugated polymers have been used for detection of a wide range of biological events, such as DNA hybridization or enzymatic activity, utilizing both electronic and optical changes in the polymer. Here the focus has been to use the polymers as optical probes to discriminate between native and misfolded protein, as well as to follow the misfolding processes in vitro. The understanding and detection of protein misfolding, for example amyloid fibril formation, is a topic of growing importance. The misfolding process is strongly associated with several devastating diseases such as Alzheimer’s disease, Parkinson’s disease and Bovine Spongiform Encephalopathy (BSE). We have developed detection schemes for discrimination between proteins in the native or amyloid fibril state based on luminescent polythiophene derivatives. Through a synthesis strategy based on polymerization of trimer blocks rather than of monomers, polythiophene derivatives with higher optical signal specificity for amyloid-like fibrils were obtained. Self-assembly of nanowires containing conjugated polymers is a route to generate structures of unique opto-electrical characteristics without the need for tedious topdown processes. Biomolecules can have nanowire geometries of extraordinary aspect ratio and functionalities. The DNA molecule is the most well known and exploited of these. In this thesis work the more stable amyloid fibril has been used as a template to organize conjugated polymers. Luminescent, semi-conducting, conjugated polymers have been incorporated in and assembled onto amyloid fibrils. Using luminescence quenching we have demonstrated that the conjugated material can retain the electro-activity after the incorporation process. Furthermore, the amyloid fibril/conjugated polymer hybrid structures can be organized on surfaces by the means of molecular combing and soft lithography. In the process of generating self-assembled biomolecular nanowires functionalized with conjugated polymers, we have shown a new synthesis strategy for a water-soluble highly conducting polythiophene derivative. This material, PEDOT-S, has shown affinity for amyloid fibrils, but can also be very useful in conventional opto-electronic polymer-based devices.

In order to study their electrochemical and optical properties, two donor-acceptordonor (D-A-D) type monomers / 4&#039 / -(tert-butyl)-4,7-bis(4-hexylthiophen-2- yl)spiro[benzo[d]imidazole-2,1&#039 / -cyclohexane] (BIHT) and 4&#039 / -(tert-butyl)-4,7-bis(2,3- dihydrothieno[3,4-b][1,4]dioxin-5-yl)spiro[benzo[d]imidazole-2,1&#039 / -cyclohexane] (BIED), were electrochemically polymerized. These properties were investigated by cyclic voltammetry and UV&ndash / Vis-NIR Spectroscopy techniques. Effects of different donor groups / 3-hexylthiophene and 3, 4-ethylenedioxythiophene (EDOT), on new benzimidazole group, 4&#039 / -(tert-butyl)spiro[benzo[d]imidazole-2,1&#039 / -cyclohexane], were investigated. These pendant groups cause slight differences in optical band gaps, which are 1.19 eV for PBIHT, 1.15eV for PBIED. PBIHT and PBIED have both nand p- doping. Both of them have broad absorption in the visible region. In NIR region, both polymers revealed 46 % transmittance with high switching times. PBIED and PBIHT showed multichromic properties. PBIED is green at neutral state. For the most oxidized and reduced states, it is blue and red, respectively. PBIHT is blue at neutral state, transmissive-gray in oxidized state and transmissive greenishgray in reduced state.