Este trabalho tem como principais objetivos: desenvolver procedimentos sintéticos e novos materiais poliméricos que apresentem boa condutividade elétrica, estudar o comportamento eletro-óptico dos polímeros obtidos, desenvolver procedimentos para a construção de dispositivos eletroluminescentes, caracterizá-los e correlacionar as características eletro-ópticas observadas com a constituição da camada ativa polimérica. Foram realizadas diversas sínteses objetivando a preparação de polifluorenos com diferentes estruturas químicas a partir de monômeros difuncionais aromáticos boronados e bromados, utilizando uma mesma rota de acoplamento de Suzuki. Assim, foram preparados três polímeros, poli[2,7-(9,9-dioctilfluoreno)] (PF, polifluoreno), poli[1,4-fenileno-alt-2,7- (9,9-dioctilfluoreno)] [PFP, poli(fluoreno-fenileno)] e poli[(1,4-fenileno-2-flúor)-alt-2,7-(9,9- dioctilfluoreno)] [PFPF, poli(fluoreno-fenileno)fluorado]. Para obtenção destes polifluorenos com bom rendimento e com pureza adequada para a preparação de dispositivos poliméricos eletroluminescentes, foi necessário testar diversas condições de reação, até a otimização de um procedimento sintético robusto. Os polifluorenos preparados foram exaustivamente purificados por extração e solubilização-precipitação. Todos os polifluorenos tiveram a sua estrutura e composição químicas caracterizadas e confirmadas pelas técnicas de espectroscopia no infravermelho (FTIR), espectroscopia de ressonância magnética nuclear de hidrogênio (¹HNMR) e espectroscopia de energia dispersiva de raios-X (EDX). As massas molares médias e a polidispersão foram determinadas por cromatografia de permeação em gel (GPC). Soluções em clorofórmio dos polifluorenos foram analisadas por espectroscopias de absorção e emissão no UV-Vis. Estes resultados nos forneceram informações importantes quanto às propriedades de fotoluminescência dos polifluorenos obtidos. Até o momento, sabe-se que todos os três polímeros emitem cor azul e dentre as três estruturas estudadas, o PFPF apresentou maior intensidade de fluorescência. Para a fabricação dos P-OLEDs (Diodos Orgânico-Polimérico Emissor de Luz) foram feitas soluções de clorofórmio em concentrações de 1% dos três tipos de polímeros. Também foi estudada a influência dos compostos ETL (electron transport layer) (Alq3 ou butyl-PBD) com concentrações de 0,5%. Quando aplicada uma tensão no dispositivo, o PFPF apresentou menor tensão de operação entre os polímeros estudados. A partir das curvas de tensão vs. corrente, verificou-se que a adição do butyl-PBD nos três tipos de polímeros diminui a tensão de limiar em comparação com os dispositivos sem composto ETL. Os comprimentos de onda de eletroluminescência dos dispositivos polarizados permaneceram constante mesmo com a adição dos dois compostos ETL (Alq3 ou butyl-PBD). / This work has as main objectives: develop synthetic procedures and new electroluminescent polymeric materials that have good electrical conductivity, study the behavior of polymer systems thus obtained, and develop procedures for the construction of electroluminescent devices, characterize them and correlate the photo- electrical behavior with the features of the constitutive active polymeric layer Several syntheses were performed aiming at preparing polyfluorenes with different structures from boronated and brominated difunctional aromatic monomers using a Suzuki coupling route. So far, three polymers were prepared, poly[2,7-(9,9-dioctylfluorene)] (PF, polyfluorene), poly[1,4-phenylene-alt-2,7-(9,9-dioctylfluorene)] [PFP, poly(fluorenephenylene)] and poly[1,4-phenylene-2-fluoro)-alt-2,7-(9,9-dioctylfluorene)] [PFPF, fluorinated poly(fluorene-phenylene)]. To obtain these polyfluorenos with good yield and purity suitable for preparing polymeric electroluminescent devices, it was necessary to test various reaction conditions and to optimize a robust synthetic procedure. The polyfluorenes prepared were thoroughly purified by extraction and solubilization-precipitation. All polyfluorenes have had their structures and chemical composition characterized and confirmed by infrared spectroscopy (FTIR), and hydrogen and carbon-13 nuclear magnetic resonance spectroscopy (¹HNMR and 13CNMR). The average molar masses and polydispersity were determined by gel permeation chromatography (GPC). Polyfluorenes in chloroform solutions were analyzed by the UV-Vis absorption and emission spectroscopy. These results provided us with important information regarding the photoluminescence properties of polyfluorenes thus obtained. Until now, it is known that all three polymers emit in the blue region and among the three structures, the PFPF has the highest fluorescence intensity. The construction of PLEDs was carried out from the chloroform solutions at concentrations of 1% for each of the all three types of polymers. The influence of an ETL (electron transport layer) compound (Alq3, PBD) was also studied, and its concentration was kept constant at 5% in the polymer solution. Tests of the devices under applied voltage have shown a higher stability for PFPF among all. From the voltage vs. current curves, it was possible to observe that the addition of PBD decreased the threshold voltage for the devices prepared from the three types of polymers. The wavelength of electroluminescence remained constant despite the addition of the ETL compound (Alq3 or butyl-PBD).

Les travaux de recherche effectués lors de cette thèse s'articulent autour de deux matériaux carbonés: les nanotubes de carbone et le graphène. Leur point commun réside dans la technique de mise en suspension qu'est la dissolution douce. Cette méthode se base sur la réduction des nanostructures carbonées en polyélectrolytes, autrement dit en nanostructures chargées négativement. Nous nous sommes intéressés d'une part à la préparation et à l'étude de films transparents conducteurs à base de nanotubes de carbone pour des applications en électronique organique en tant qu'électrode transparente et en électrochimie. D'autre part, les travaux présentent une étude des solutions de graphène. Nous nous sommes notamment attachés à démontrer la présence de graphène en suspension dans certains solvants organiques par analyse directe de ces solutions. / Two carbon materials have been studied during this thesis: carbon nanotubes and graphene. Their common point is the method used to prepare suspensions which is the mild dissolution. Using this method, carbon nanostructures can be reduced into polyelectrolytes, id. into negatively charged nanostructures. The first part deals with transparent and conductive films of carbon nanotubes which have been prepared and studied as transparent electrode for electronic applications and for electrochemistry. The second part of this work deals with graphene in solution in different solvents. The aim of this work was to show the presence of graphene by direct analysis of these graphene solutions.

The deformation between interface, adhesion mechanism and the transparency of multi-layer flexible electronics composite were discussed. First, ITO (Indium Tin Oxide), Al (Aluminum) and ZnO (Zinc Oxide) were sputtered on a PET (Poly Ethylene Terephthalate) substrate by PVD (Physical Vapor Deposition) sequentially, to form ZnO/ITO/PET and ZnO/Al/PET which is the essential multi-layer structure in the transducer of flexible electronics. ITO/PET structure was widely applied to the touch panel. PET substrate possesses a good optical penetrability, low thermal expansion coefficient and lower price. However, the heat-resisting and chemical stability are poor. In this study, we explore the feasibility of the PDMS (Polydimethylsiloxane) substrate. It not only possesses good optical penetrability, but also exhibits higher PH selectivity than PET. In the analysis, the periodic external force was pressed on the flexible composite films to realize the difference between before and after experiment. Then the composite films were examined by nanoindentation and nanoscratch system (Berkovich and Conical probe with the radius of curvature of 20nm and 10um), four-point probe and spectrometer to measure the mechanical, electrical and optical properties, respectively. To investigate the effect of external force on these composite films, the interaction of films was discussed through external force testing by nanoscratch test.

Indium tin oxide (ITO) thin films were formed on glass substrates by sol-gel method. Coating sols were prepared using indium chloride tetrahydrate (InCl3&bull / 4H2O) and tin-chloride pentahydrate (SnCl4&bull / 5H2O) stabilized in organic solvents (acetylacetone and ethanol). First attempt was to synthesize ITO thin films using standard/unmodified coating sols. The effect of calcination treatment in air (300 &ndash / 600 &deg / C) and number of coating layer(s) (1, 4, 7 or 10) on optoelectronic properties (electrical conductivity and optical transparency), crystal structure and microstructure of ITO thin films were investigated. In addition, single-layer ITO thin films with optoelectronic properties comparable to multi-layered films were prepared by employing organically modified coating sols. Oxalic acid dihydrate (OAD) &ndash / a drying/microstructure control agent&ndash / addition to standard sol formulation was achieved. The rationale was to improve the optoelectronic properties of ITO films through enhancement in microstructure and chemical characteristics upon OAD addition. The effects of OAD content in the sol formulation and post-coating calcination treatment on electrical/optical properties of ITO films have been reported. Finally, the effects of post coating drying temperature (100 &ndash / 200 &deg / C) and time (10 &ndash / 60 min) on optoelectronic and microstructural properties of OAD-modified ITO thin films were discussed. Thin films have been characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD),x-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-Vis) spectroscopy, fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and four-point probe measurement techniques. It was shown that film formation efficiency, surface coverage and homogeneity were all enhanced with OAD addition. OAD modification also leads to a significant improvement in electrical conductivity without affecting the film thickness (45&plusmn / 3 nm). Highly transparent (98 % transmittance in visible region) ITO thin films with a sheet resistance as low as 3.8&plusmn / 0.4 k&Omega / /sqr have been obtained by employing coating sols with optimized OAD amount (0.75 M). The optimum post-coating drying temperature (100 &deg / C) and drying time (10 min) was also determined for 0.75 M OAD-modified ITO thin films.

In the past few years, the synthesis and fabrication of inorganic nanostructures with manipulated morphology and size have attracted considerable attention due to their fundamental importance and potential wide-ranging applications. Silver nanowires are particularly interesting to study because bulk silver has the highest electric conductivity among all metals. A number of chemical approaches have been explored to synthesize 1D silver nanowires. We demonstrate a simple method to synthesize silver wires by thermal reduction of aqueous AgNO3 droplet with catalytic anatase TiO2 nanoparticles which were spin-coated on ITO or glass. Our simple method can be also applied to generate CuO with donut-shaped microstructure by using ITO conducting glass as matrix. We have found that the size and reproducibility are well-controllable. A single phase of CuO donut-shaped microstructure with outer diameters ranging from ∼ 13 to 17 £gm and inner diameters ranging from ∼ 1.4 to 3.3 £gm was obtained. The composition of CuO microdonut was confirmed by thin-film XRD and XPS analyses.

The Black-Scholes European option pricing formula can be derived in several ways. In this dissertation we present several methods that can be used to derive this formula, including partial differential equation method, the risk-neutral pricing method, the martingale measure method, and the change of numeraire technique

Organic photovoltaics (OPVs) offer the prospect of inexpensive processing compared with conventional crystalline semiconductor cells. These cells are still lower in efficiency than their inorganic counterparts, in part because a detailed understanding of the role that interfaces play in these devices is lacking. The electronic properties of the surface of the common transparent electrode Indium:Tin Oxide (ITO) have been studied both on a macroscopic and nanoscopic scale, and the interface between ITO and organic materials has been studied on a macroscopic scale as well. Little work has been done on the nanoscopic properties of the ITO/organic interface. This dissertation introduces a new conducting-probe atomic force microscope (CP-AFM) technique, Scanning Current Spectroscopy (SCS), for probing the nanoscopic lateral variation in the electronic properties of this interface, and demonstrates its utility by examining the ITO/copperphthalocyanine (CuPc) interface. SCS demonstrates large lateral variations in the hole collection efficiency at that interface on a nanometer length scale, and that the distribution of these variations is affected by ITO pretreatment. Measurements on OPVs demonstrate that the performance of these devices is dependant on the nanoscopic lateral variation in surface properties that SCS measures, and that in the case of the ITO/CuPcinterface SCS explains the observed device behavior better than techniques that yield macroscopic average electronic properties, such as photoelectron spectroscopy. Additionally, this dissertation discusses advances made in the design of an integrated optical refractive index sensor. The sensor uses organic light-emitting diodes (OLEDs) and OPVs as integrated light-sources and detectors on top of a slab waveguide substrate. The platform offers potentially high sensitivities to refractive index changes (and the selective binding of chemical and biological analytes), and is amenable to largescale integration for on-chip multiplexed detection. The refractive index response has been demonstrated previously, but the performance was limited by electrical noise and OLED drift. The use of different absorbing species in the OPV, integration of multiplesensors on a single substrate, addition of a reference channel to monitor OLED drift andthe use of lock-in amplification for signal processing allow the sensor to detect changesof 10-4 refractive index units.

Thesis (Ph. D.)--University of Washington, 1990. / Vita. Includes bibliographical references (leaves [420]-434).

Made available in DSpace on 2014-06-12T18:03:47Z (GMT). No. of bitstreams: 2 arquivo4176_1.pdf: 3353593 bytes, checksum: 96a4aaadd82e2069974188be9b191586 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Universidade Federal de Pernambuco / Desenvolveu-se um processo de produção de filmes finos de óxido de índio dopado com estanho (ITO) com espessuras típicas de 120 nm, depositados em substratos de vidro pela técnica de evaporação térmica reativa (ETR). Os efeitos da pressão parcial de oxigênio durante a deposição e do tratamento térmico em oxigênio nas propriedades elétricas, estruturais e óticas dos filmes foram estudados. Mostramos que a técnica de ETR pode ser utilizada para produzir filmes finos de ITO com alta qualidade, baixa resistividade elétrica (10−3 .cm) e alta transmitância ( 80% na faixa visível). Os resultados obtidos suportam o potencial da utilização de filmes finos de ITO produzidos por ETR para aplicação em dispositivos semicondutores, fotônicos, optoeletrônicos, sensores e detectores. Desenvolveu-se também processos de produção de filmes de silício poroso pelas técnicas de corrosão eletroquímica (CE) e corrosão a vapor (CV). O efeito dos eletrodos de níquel e paládio nas propriedades do silício poroso foram estudados e comparados com os filmes de silício poroso sintetizados por outra técnica (CE com eletrodo de platina e CV). Mostramos que o efeito catalítico do eletrodo utilizado durante a CE, em especial o efeito do eletrodo de paládio, pode ser utilizado para produzir silício poroso de alta qualidade estrutural e com alta luminescência quando comparados com os sintetizados por outra técnica. Os resultados obtidos suportam o potencial dos filmes de silício poroso para aplicação em dispositivos fotônicos e optoeletrônicos.

I den här uppsatsen undersöker jag hur platserna Kurouzu-cho från Junji Itos Uzumaki och Område X från Jeff VanderMeers Annihilation framställs ur ett ekokritiskt perspektiv. Detta genom att titta på växtligheten och naturfenomen, attityder kring platserna, hus och byggnader, samt hur platserna förhåller sig till begreppet agens. Bland annat används Timothy Mortons bok Ecology without Nature och Bruno Latours artikel Agency at the Time of the Anthropocene. Slutligen sammanfattas och diskuteras detta. Jag kommer fram till att platserna nästan fungerar som karaktärer.