ZnO material based hetero-junctions are a potential candidate for the design andrealization of intrinsic white light emitting devices (WLEDs) due to several advantages overthe nitride based material system. During the last few years the lack of a reliable andreproducible p-type doping in ZnO material with sufficiently high conductivity and carrierconcentration has initiated an alternative approach to grow n-ZnO nanorods (NRs) on other ptypeinorganic and organic substrates. This thesis deals with ZnO NRs-hetero-junctions basedintrinsic WLEDs grown on p-SiC, n-SiC and p-type polymers. The NRs were grown by thelow temperature aqueous chemical growth (ACG) and the high temperature vapor liquid solid(VLS) method. The structural, electrical and optical properties of these WLEDs wereinvestigated and analyzed by means of scanning electron microscope (SEM), current voltage(I-V), photoluminescence (PL), cathodoluminescence (CL), electroluminescence (EL) anddeep level transient spectroscopy (DLTS). Room temperature (RT) PL spectra of ZnOtypically exhibit one sharp UV peak and possibly one or two broad deep level emissions(DLE) due to deep level defects in the bandgap. For obtaining detailed information about thephysical origin, growth dependence of optically active defects and their spatial distribution,especially to study the re-absorption of the UV in hetero-junction WLEDs structure depthresolved CL spectroscopy, is performed. At room temperature the CL intensity of the DLEband is increased with the increase of the electron beam penetration depth due to the increaseof the defect concentration at the ZnO NRs/substrate interface. The intensity ratio of the DLEto the UV emission, which is very useful in exploring the origin of the deep level emissionand the distribution of the recombination centers, is monitored. It was found that the deepcenters are distributed exponentially along the ZnO NRs and that there are more deep defectsat the root of ZnO NRs compared to the upper part. The RT-EL spectra of WLEDs illustrateemission band covering the whole visible range from 420 nm and up to 800 nm. The whitelightcomponents are distinguished using a Gaussian function and the components were foundto be violet, blue, green, orange and red emission lines. The origin of these emission lines wasfurther identified. Color coordinates measurement of the WLEDs reveals that the emitted lighthas a white impression. The color rendering index (CRI) and the correlated color temperature(CCT) of the fabricated WLEDs were calculated to be 80-92 and 3300-4200 K, respectively.

Nanotechnology is an emerging inter-disciplinary paradigm which encompasses diverse fields of science and engineering converge at the nanoscale. This nanoscale science and nanostructure engineering have well demonstrated in the fabrication of sensors/transducers devices with faster response time and better sensitivity then the planer version of the sensor’s configurations. Nanotechnology is not just to grow/fabricate nanostructures by just mixing nanoscale materials together but it requires the ability to understand and to precisely manipulate and control of the developed nanomaterials in a useful way. Nanotechnology is aiding to substantially improve, even revolutionize, many technology and industry sectors like information technology, energy, environmental science, medicine/medical instrumentation, homeland security, food safety, and transportation, among many others. Such applications of nanotechnology are delivering in both expected and unexpected ways on nanotechnology’s promise to benefit the society. The semiconductor ZnO with wide band gap (~ 3.37 eV) is a distinguish and unique material and its nanostructures have attracted great attention among the researchers due to its peculiar properties such as large exciton binding energy (60 meV) at room temperature, the high electron mobility, high thermal conductivity, good transparency and easiness of fabricating it in the different type of nanostructures. Based on all these fascinating properties, ZnO have been chosen as a suitable material for the fabrication of photonic, transducers/sensors, piezoelectric, transparent and spin electronics devices etc. The objective of the current study is to highlight the recent developments in materials and techniques for electrochemical sensing and hetrostructure light emitting diodes (LEDs) luminescence properties based on the different ZnO nanostructures. The sensor devices fabricated and characterized in the work were applied to determine and monitor the real changes of the chemical or biochemical species. We have successfully demonstrated the application of our fabricated devices as primary transducers/sensors for the determination of extracellular glucose and the glucose inside the human fat cells and frog cells using the potentiometric technique. Moreover, the fabricated ZnO based nanosensors have also been applied for the selective determination of uric acid, urea and metal ions successfully. This thesis relates specifically to zinc oxide nanostructure based electrochemical sensors and photonic device (LED) applications.

One-dimensional ZnO nanostructures have great potential applications in the fields of optoelectronic and sensor devices. Therefore, it is really important to realize the controllable growth of one-dimensional ZnO nanostructures and investigate their properties. The main points for this thesis are not only to successfully realize the controllable growth of ZnO nonawires, nanorods and quantum dots (QDs), and also investigate the structure and optical properties in detail by the methods of scan electron microscope(SEM), transmission electron microscope(TEM), resonant Raman, photoluminescence(PL) and low-temperature time resolved PL spectrum. to grown ZnO nanorod arrays (ZNAs) on Si substrates. Firstly, the effects of ZnO nanoparticles, pH value of chemical solution, angel θ between substrate and beaker bottom on the structures of the samples were symmetrically investigated and the optimized growth condition to grow ZNAs can be concluded as follows: seed layer of ZnO nanoparticles, pH=6 and θ=70°. On the basis of these, the diameter of ZNAs was well controlled from 150nm~40nm through adjusting the diameter and density of the ZnO nanoparticles pretreated on the Si substrates. The experimental results indicated that both diameter and density of ZnO nanoparticles on the substrates determined the diameter of ZNAs. But when the density is higher than the critical value of 2.3×108cm-2, the density will become the dominant factor to determine the diameter of ZNAs. One the other hand, the optical properties of ZNAs were investigated in detail. The Raman and photoluminescence (PL) results showed that after an annealing treatment around 500oC in air atmosphere, the crystal structure and optical properties became much better due to the decrease of surface defects. The resonant Raman measurements excited by 351.1nm not only revealed that the surface defects play a significant role in the as-grown sample, but also suggested that the strong intensity increase of some Raman scatterings was due to both outgoing resonant Raman scattering effect and deep level defects scattering contribution for ZnO nanorods annealed from 500°C to 700°C. It is the first time to the best of our knowledge that the Raman measurements can be used to monitor the change of surface defects and deep level defects in the CBD grown ZnO nanorods. We have also presented, for the first time, a time resolved PL study in CBD grown ZnO nanorods with different diameters. The results show that the decay time of the excitons in the nanorods strongly depends on the diameter of the nanorods. The altered decay time is mainly due to the surface recombination process. The effective time constant related to the surface recombination velocity was deduced. A thermal treatment under 500°C will suppress the surface recombination channel, resulting in an improvement of the optical quality for the ZnO nanorods. This thesis not only provides the effective way to control the size of ZNAs, but also obtains some beneficial results in aspects of their optical properties, which builds theoretical and experimental foundation for much better and broader applications of one-dimensional ZnO nanostructures.

Ultimamente têm-se buscado tratamentos menos invasivos para o câncer, como os que utilizam campos magnéticos ou luz, e dentre esses últimos, aqueles que fazem uso de materiais, geralmente metálicos, com propriedade de ressonância plasmônica de superfície. O tratamento hipertérmico encaixa-se neste perfil e já apresenta resultados promissores com nanoshells de sílica recoberta por ouro e com nanobarras de ouro maciço, apesar de pouco se saber sobre o mecanismo de ação e sobre como as vias de morte celular são ativadas em tal tratamento. A síntese das nanobarras envolve o uso do composto brometo de cetiltrimetilamônio (CTAB), o qual permanece aderido à superfície das mesmas, porém é caracterizado por apresentar extrema citotoxicidade, fato que incita a modificação do recobrimento das nanopartículas por um biopolímero mais compatível. Estudos recentes indicam que o CTAB aderido à membrana não apresenta citotoxicidade considerável, porém há poucos dados que confirmem tal hipótese na literatura. Este trabalho se propôs a investigar a via de ativação da morte celular, bem como confirmar a hipótese de que as partículas recobertas por CTAB podem ser utilizadas para tratamento antitumoral fototérmico in vivo de forma segura. Para isso, nanobarras de ouro foram sintetizadas pelo método de seeding, sendo parte delas centrifugadas e lavadas com água deionizada por três vezes para retirar o CTAB e a outra parte deixada com CTAB no meio. As partículas foram testadas in vitro pelo teste de citotoxicidade pelo [brometo de 3-(4, 5-dimetiltiazol-2-yl)-2,5-difeniltetrazólio] (MTT) nas linhagens celulares HTC, HepG2, HT-29 e 786-O, e também foram testadas quanto à sua viabilidade com o tempo decorrido desde sua síntese. Após confirmar que as nanobarras centrifugadas e lavadas podem ser utilizadas no tratamento hipertérmico sem riscos à saúde e após verificar que as seeds e as nanobarras devem ser utilizadas até 48 horas depois de sua síntese, as nanopartículas foram utilizadas para tratamento de tumor de Ehrlich (induzido no dorso de camundongos). Para isso, foram organizados quatro grupos experimentais: L (camundongos não receberam nanopartículas, irradiados com laser em 808 nm), N (camundongos receberam nanopartículas, não irradiados com laser), H (camundongos receberam nanopartículas e irradiados com laser em 808 nm) e Controles (camundongos não receberam nanopartículas nem irradiação por laser). O material tumoral foi coletado após a irradiação e submetido à análise histológica, ao teste de quimiluminescência para avaliar a lipoperoxidação de membrana e ao teste de TRAP (do inglês, Total Radical-Trapping Antioxidant Parameter) para avaliar a capacidade antioxidante total. Após a irradiação com 2 W/\'CM POT.2\' ou 720 mW/\'CM POT.2\' de intensidade, houve evidente redução do volume tumoral nos animais do grupo H tratados com laser na maior potência utilizada, com um aumento de 47ºC (temperatura final de 79ºC) observado localmente. Nos animais do grupo H tratados com laser na menor potência utilizada, os danos foram menores. Os animais dos grupos L e H apresentaram semelhante lipoperoxidação, maior que no grupo N (estatisticamente significante somente nos animais tratados com laser em intensidade de 2 W/\'CM POT.2\'), e a capacidade antioxidante dos tumores dos animais do grupo H foi elevada no protocolo com laser em 2 W/\'CM POT.2\'. Os resultados indicam que a necrose é a via de morte ativada prioritariamente neste caso e que o tratamento com as nanobarras se mostrou eficaz. / Less invasive cancer treatments, likewise those based on magnetic fields or light, are in the most common aims of researchers nowadays. Regarding light based treatments, those in which metallic, plasmonic materials are highlighted in research field. Hiperthermic treatment fits this profile, once it already presents promising results with gold-coated silica nanoshells and with gold nanorods, although little is known about its action mechanism or about how cell death pathways are activated. The compound cetyltrimethylammonium bromide (CTAB) is necessary for the nanorods synthesis, but is known to be extremely cytotoxic, fact that instigates the modification of nanorods surface coating by a compatible biopolymer. Recent studies indicate that surface-adhered CTAB does not present significant cytotoxicity, but there are few evidences to confirm this hypothesis in the literature. This study aims to investigate the cell death pathway that can be activated, as well as to confirm the possibility of safe CTAB-coated nanoparticles use in antitumor in vivo treatments. For that, gold nanorods were synthesized by the seeding method and part of them were centrifuged and washed with deionized water to eliminate CTAB of the solution and the rest remained with CTAB. The particles were tested in vitro by [3-(4, 5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) cytotoxicity test, in HTC, HepG2, HT-29 and 786-O cancer cell lines, and investigated regarding their viability through time after their synthesis. After confirming that centrifuged and washed nanorods can be used in hiperthermic therapy without health risks, and after find out that seeds and nanorods must be used within 48 hours after their synthesis, those nanoparticles were used for in vivo hyperthermic Ehrlich tumor (induced on the back of mices) treatment. Four experimental groups were organized: L (mice did not receive nanoparticles, treated with laser at 808 nm), N (mice received nanoparticles, not treated with laser), and H (mice received nanoparticles and treated with laser at 808 nm) and Controls (mice did not receive nanoparticles and were not treated with laser). A tumor biopsy was taken after laser irradiation and was subjected to histological analysis, by a chemiluminescence assay to evaluate membrane lipoperoxidation, and by Total Radical-Trapping Antioxidant Parameter (TRAP) assay as well, to evaluate total antioxidant capacity. After irradiation with laser (intensities of 2 W/\'CM POT.2\' or 720 mW/\'CM POT.2\'), there was an evident tumor volume reduction in animals of H group treated with higher power laser, with a 47ºC rise in temperature (final temperature was 79ºC) observed locally. The damages in the tumors irradiated with lower power laser were less intense. The animals of L and H groups showed similar membrane lipoperoxidation, which was more intense than in N animals (statistically significant just in the animals treated with higher intensity of radiation). The antioxidant capacity of H animals tumor was elevated also in the animals treated with higher energy. Our results indicate that necrosis is the main activated cell death pathway in this case, and that nanorods treatment is worth it.

Orientador: Oswaldo Luiz Alves / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-11T15:46:56Z (GMT). No. of bitstreams: 1 Vieira_LucianaLima_M.pdf: 10012169 bytes, checksum: 3526b70650ff03af91d229d38c75c1e4 (MD5) Previous issue date: 2008 / Resumo: Esta dissertação visa à obtenção de nanoestruturas de sulfeto de molibdênio e sulfeto de tungstênio partindo dos respectivos óxidos com morfologia de nanobastões. Os óxidos precursores foram preparados via rota hidrotérmica (MoO3 e W18O49) via rota térmica (WO3). Os sulfetos foram preparados a partir da reação sólido-gás dos óxidos em atmosfera de H2S. Os nanobastões de óxido de molibdênio foram preparados através do tratamento hidrotérmico do MoO3·2H2O em solução aquosa de ácido acético a 180 °C durante 7 dias. Os nanobastões de MoO3 com diâmetro médio de 150 nm foram submetidos à atmosfera de H2S e H2 5% / N2 95% a 800 °C, obtendo-se como produto nanobastões de sulfeto de molibdênio. Nanobastões de W18O49 foram preparados pelo tratamento hidrotérmico do ácido túngstico (WoO3·nH2O) na presença de sulfato de sódio (0-30 g) e possuem diâmetro de 5- 15 nm. Foi observado que o sulfato de sódio possui um papel importante como direcionador de fase e morfologia do óxido de tungstênio. A sulfidização dos nanobastões de W18O49 foi realizada na presença e na ausência de atmosfera redutora. Em ambos os casos foram obtidos como produto WS2 com morfologia de nanobastões e/ou nanopartículas. Por ser uma fase parcialmente reduzida, não foi necessária a presença de gás hidrogênio para a preparação de nanoestruturas de WS2 através desta rota. Nanobastões de WO3 triclínico foram obtidos através do tratamento térmico de óxido de tungstênio não cristalino (proveniente da reação entre WCl6 e metanol) em atmosfera de nitrogênio a 600-1000 °C. Os nanobastões foram sulfidizados a 800 °C em atmosfera de H2S obtendo-se como produto nanotubos de WS2 com diâmetro entre 20 e 180 nm. Tal rota se mostrou eficiente quanto ao rendimento morfológico, e também interessante na medida que temos um número menor de etapas de síntese envolvidas na obtenção da morfologia e fase desejada. Também foram feitos experimentos de sulfidização alternativa para óxidos de molibdênio e tungstênio sobre condições hidrotérmicas. Tais reações foram realizadas em meio aquoso e utilizando agentes sulfidizantes (compostos que podem gerar H2S ou íons S2-), tais como enxofre, tioacetamida e tiouréia. A sulfidização do óxido de molibdênio foi efetiva, formando sulfeto de molibdênio. Os sulfetos apresentam uma interessante mudança de morfologia do agregado dependendo do tipo de preparação de amostras para microscopia eletrônica, apresentando-se na forma de flores quando a preparação é feita através do tratamento da suspensão aquosa do sólido em ultrassom. A sulfidização alternativa do óxido de tungstênio, por sua vez, não foi efetiva, uma vez que não produz sulfeto de tungstênio, mas apenas a redução parcial do óxido. Porém, nanoestruturas unidimensionais de W18O49 são formadas quando este óxido é submetido a tratamento térmico sob atmosfera inerte. Este óxido mostrou-se bastante interessante para as reações de sulfidização em H2S, uma vez que também pode ser utilizado para a preparação de nanoestruturas cilíndricas de WS2 / Abstract: The main of this Dissertation is the preparation of nanostructured WS2 and MoS2 from a template reaction with the respective nanorods oxides. Molybdenum oxide nanorods with diameters around 100 nm and microscale lengths were prepared from MoO3·2H2O via a one step solvothermal reaction. The formation of MoO3 rods proceeds in acidic media at 180 °C. The oxide was converted in quantitative yield to MoS2 nanorods by H2S in a reducing atmosphere. TEM and SEM analysis reveals that the rod-like morphology of the oxide precursor is preserved during the H2S treatment. Monoclinic W18O49 nanorods of 5¿15 nm in diameter have been synthesised by a low temperature hydrothermal route using sodium sulfate as structural and morphological modifier. The important role of Na2SO4 salt in the synthesis has been demonstrated. These nanorods were found suitable as a precursor for the synthesis of nanostructured WS2 by reducing them with H2S at 800 °C for 30 min. This reaction can work out without a reducing atmosphere. The morphological and structural features of WS2 nanotubes, generated from WO3 nanorods, by an in situ heating process, have been studied. The nanorods were prepared by a simple annealing method of a low-crystalline tungsten oxide (from a sol-gel reaction between WCl6 and methanol) at 600-1000 °C. Finally, an alternative route to molybdenum and tungsten sulfide by solution chemical reactions was also explored. The reaction was carried out from the respective oxides and sulfurization reagents such as S, CH3CSNH2 and CSN2H4 through hydrothermal method. MoS2 nanostructures including flower-like particles have been synthesized. The hydrothermal reaction with tungsten has not produced WS2 but W18O49 nanorods after thermal annealing. These oxides were converted in nanostructured WS2 by solid-gas reaction in H2S atmosphere at 800°C / Mestrado / Quimica Inorganica / Mestre em Química

Embora exista considerável progresso na área de biossensores, ainda é primordial aprimorar muitos desses dispositivos. Este trabalho tem por objetivo contribuir para o contínuo crescimento dos biossensores a base de enzimas e de moléculas de DNA, sendo dois biossensores eletroquímicos descritos. O primeiro trata-se de um biossensor enzimático utilizando tirosinase (Tyr) imobilizada por intermédio de cistamina (CYS) e glutaraldeído (GA) para a detecção de compostos fenólicos. Eletrodos de carbono impressos (SPCE) foram modificados com nanobastões de ouro (AuNRs) em filme de poli(amido amina) (PAMAM) geração 4 para o favorecimento da transferência direta de elétrons (DET) entre o eletrodo e o sítio ativo da enzima. Para caracterizar os AuNRs e AuNRs-PAMAM, espectroscopia de absorção no UV-Visível, espalhamento de luz dinâmico (DLS) e microscopia eletrônica de varredura (SEM) foram empregadas. As etapas do biossensor foram estudadas por voltametria cíclica e linear, amperometria e microscopia de força atômica (AFM) na presença de dois analitos: catecol (CAT) e dopamina (DA). A faixa linear para CAT foi de 2,8 a 30,3 μmol L-1 com um limite de detecção (LD) de 1,0μmol L-1 enquanto para a DA, a faixa linear foi de 27,8 a 448,7 μmol L-1 e LD de 10,0 μmol L-1. Além de apresentar ótima resposta frente a possíveis interferentes, o sensor também mostrou excelente desempenho em amostras reais, que atrelados aos testes de repetibilidade e reprodutibilidade mostram a estabilidade e acurácia do biossensor. O segundo sensor, trata-se de um sensor de DNA impedimétrico em eletrodo de ouro para a detecção da mutação c.68_69del relacionada à predisposição ao câncer de mama. A imobilização da sequência de captura (SH-ssDNA) no eletrodo ocorreu pela ligação ouro-enxofre (Au-S) e o modelo de hibridização escolhido foi a hibridização direta. O genossensor distinguiu eficientemente entre as sequências alvo (tarDNA) e não-complementar (ncsDNA), apresentando faixa linear de 1,0 a 200,0 nmol L-1 e LD de 0,14 nmol L-1. Os resultados sugerem que ambos biossensores têm potencial e que as estratégias propostas são promissoras para o desenvolvimento de outros biossensores. / Despite a considerable progress in the area of biosensors, it is still crucial to improve most of these sensors. This study aims to contribute to the ongoing growth of enzyme- and DNA-based biosensors, being described two electrochemical biosensors. The first one is an enzyme-based biosensor with immobilized Tyrosinase (Tyr), through cystamine (CYS) and glutaraldehyde (GA), for detection of phenolic compounds. Screen-printed carbon electrodes (SPCE) were modified by gold nanorods (AuNRs) stabilized with poly(amide amine) PAMAM generation 4 to facilitate direct electron transfer (DET) between electrode and enzyme active site. AuNRs and AuNRs-PAMAM were characterized using UV-Visible absorption spectroscopy, dynamic light scattering (DLS) e scanning electron microscopy (SEM). Biosensor stages were studied by cyclic and linear voltametry, amperommetry and atomic force microscopy (AFM) and tested agains two analytes: catechol (CAT) and dopamine (DA). Detection limit (LD) for CAT is 1 μmol L-1 and linear range from 2.8 to 30.3 μmol L-1, for DA, LD is 10.0 μmol L-1 and linear range 27.8 to 448.7 μmol L-1. Besides, the biosensor shows great response in the presence of interferents, it also had an excellent performance in real samples that along with repeatability and reproducibility tests indicate stability and accuracy of the biosensor. The second sensor is an impedimetric DNA sensor prepared on gold electrode to detect c.68_69del mutation related to breast cancer predisposition. Capture sequence (HS-ssDNA) immobilization occurred due to gold-sulfur bond (Au-S) and direct hybridization was the chosen hybridization model. The genosensor was able to distinguishing between target sequence (tarDNA) and non-complementary sequence (ncsDNA) and linear range and LD were found to be 1.0 to 200.0 nmol L-1 and 0.14 nmol L-1, respectively. Results suggest both biosensors have potential and proposed strategies are promising for other biosensors development.

Cette thèse a eu pour objectif la préparation d’aimants nanostructurés sains terres rares à base d’un assemblage dense de nanobâtonnets de cobalt (Co NBs). Nous avons démontré la faisabilité d’un changement d’échelle du procédé polyol, avec des conditions d’agitation contrôlées, pour obtenir 5 g de NBs monodisperse. La modification de l’agent nucléant nous a permis de contrôler la taille et la forme des NBs conduisant à des valeurs élevées de champ coercitif. La réalisation d’aimants macroscopiques denses et robustes a été possible via la dispersion des bâtonnets dans du chloroforme et son évaporation sous champ magnétique à température ambiante. La valeur de (BH)max résultante a atteint dans le meilleur des cas une valeur de 165 kJ·m-3. Des résultats préliminaires sur la compaction d’assemblées de NBs montre que la fraction volumique magnétique peut être augmenté significativement (jusqu’à 30%). Cette étude prouve que l’approche « bottom-up» est très prometteuse pour obtenir des nouveaux matériaux magnétiques durs qui peuvent compléter le panorama des aimants permanents et combler le fossé entre les ferrites et les aimants NdFeB. / The objective of this thesis is the preparation of nanostructured rare earth free permanent magnets based on dense assemblies of Co nanorods. We demonstrate the up-scaling of the polyol process for the synthesis of 5 g of monodispersed cylindrical Co NR with controlled cylindrical-like shape. Modification of the nucleating agent allows optimizing further the nanorods’ shape, leading to the highest coercivity values measured. Dense and robust macroscopic magnets were obtained via the rods’ alignment under a magnetic field presenting an ideal hysteresis loop. Additional structural and magnetic characterization was accomplished via small angle neutron scattering. A quantitative assessment of the (BH)max values showed a maximum of 165 kJ·m-3. Preliminary compaction experiments resulted in the fabrication of bulk magnets with increased magnetic volume fraction (up to 30%). We prove that the bottom-up approach is very promising to get new hard magnetic materials that can compete in the permanent magnet panorama and fill the gap between the ferrites and the NdFeB magnets.

Philosophiae Doctor - PhD / Supercapacitors are charge-storage devices. Compared to batteries, they have higher power density, more excellent reversibility and longer cycle life. Therefore, supercapacitors have played an increasingly important role in the fields of power source especially in automotive applications, such as electric and hybrid electric vehicles. The higher power density of supercapacitors offers improved vehicle acceleration and the ability to recover more energy from regenerative breaking, since they can be charged and discharged at high current. Generally, the key for supercapacitors to achieve high specific power depends on the inherent properties and the surface areas of their electrode materials. Therefore, current research in the field of supercapacitors has been carried out with increased emphasis on the development of new electrode materials. Optimal novel synthesis of electrode materials for supercapacitor application in hybrid vehicles was accomplished with polypyrrole nanowires, manganese oxide and its carbon composites, ruthenium oxide and its carbon composites being the products. A set of structural and chemical parameters influencing the performance of synthesized electrode materials were identified. Parameters included crystallinity, particle size, particle size distribution, surface area, electrochemical activity. A large range of analytical tools were employed in characterizing the electrode materials of interest. High accuracy and precision in the quantitative and qualitative structural characterization of electrode materials collected by x-ray diffractometry, transmission electron microscopy, scanning electron microscopy and Fourier transform infra-red spectroscopy was demonstrated. N₂-physisorption produced surface area and pore size distribution data of high quality. Cyclic voltammetry, charge and discharge cycling, electron impedance spectroscopy were employed in the electrochemical characterization of the synthesized electrode materials and both qualitative and quantitative information obtained. The techniques were able to discriminate between various synthesized electrode materials and identify the highly electroactive materials. Preparation variables could be critically evaluated for the synthesis of electrode materials. The techniques were deemed to be applicable in discriminating high and low activity electrode materials based on their structural and chemical properties.

This thesis studies the different ways in which the localized plasmon heating effect of gold nanostructures -activated by plasmon excitation via visible and/or NIR irradiation- can be used to obtain different outcomes following the nanofabrication of applicable devices. Both spatial and temporal control were obtained for each one of the systems developed upon the incorporation of plasmonic gold nanostructures. Spatial control was enabled in hybrid mesoporous drug delivery systems fabricated in this thesis through the localized surface plasmon heating effect that allowed the modification of the dynamics of diffusion of the cargo being delivered, thus giving rise to different rates of release that can be controlled by plasmon excitation. At the same time, the plasmon heating effect proved to be capable of controlling the start of the release by dismantling thermo-responsive gates previously incorporated, thus enabling also a wavelength-controlled feature that enhances the versatility of these systems. Spatial control was also conferred to the photo-patterning applications presented in this dissertation by influencing the degree of motility of gold nanorods (AuNRs) embedded in polymer matrices allowing them to self-assemble when the longitudinal plasmon of the incorporated nanostructures was excited; the patterns generated were quite robust and persisted for extended periods of time. Finally, the feature of spatial heating control was also conferred to catalysis. The Friedel-Crafts alkylation of anisole by benzyl chloride using spherical gold nanoparticles (AuNPs) supported on Nb2O5-based catalysts was performed at bulk temperatures below those necessary for the reaction to occur when using bare or modified Nb2O5; this was the result of the combination of bulk and localized plasmon heating produced -both- via plasmon excitation. This also demonstrates the possibility of using plasmon excitation as an alternative heat source in this type of reactions. By combining the plasmonic properties of metallic nanostructures with those granted by mesoporous materials, polymer matrices and Nb2O5-based materials it was possible to obtain light-activated systems endowed also with temporal control and wavelength control while preserving the original properties of each systems' components. Overall, the content of this thesis describes in detail the practical aspects of combining gold nanostructures with different materials and the rationale behind the development of systems with customized and controllable properties.

Estudos com tratamento hipertérmico de tumores utilizando nanopartículas metálicas têm sido realizados durante as últimas décadas e mostram resultados bons quanto à remissão de tumores, por vezes chegando à cura completa. O mesmo acontece em relação aos tratamentos baseados em ação fotodinâmica de fotossensibilizadores. Tratamentos aliando a terapia hipertérmica com nanopartículas de ouro e a terapia fotodinâmica com diversos fotossensibilizadores tem efeito sinérgico e apresenta excelente potencial terapêutico, em que pese serem necessários mais estudos para que uma nova terapia conjunta possa ser implementada. A proposta deste trabalho foi investigar esse efeito sinérgico utilizando nanobastões de ouro complexados com fotossensibilizadores. Após a síntese dos nanobastões pelo método de seeding, a eficácia do tratamento fotodinâmico e da terapia hipertérmica, separadamente, foi investigada. A metodologia do recobrimento dos nanobastões por fotossensibilizador, em um primeiro momento, não logrou êxito com a porfirina, porém com a ftalocianina tetracarboxilada se mostrou mais eficaz. A taxa de fotodegradação da ftalocianina em solução foi investigada como parâmetro para a eficiência em geração de oxigênio singlete. Após centrifugação e lavagem das nanopartículas, no entanto, evidenciou-se por espectrofotometria que o fotossensibilizador não permaneceu aderido aos nanobastões. Em um segundo momento, optamos por recobrir os nanobastões por porfirinas tetrassulfonadas, com ou sem grupamentos metil-glucamina. Após o processo de recobrimento, essas ftalocianinas formaram complexos iônicos com o CTAB que recobre os nanobastões. Os complexos nanobastões-ftalocianinas foram analisados por microscopia eletrônica de transmissão e as taxas de geração de oxigênio singlete e de radical hidroxil foram investigadas. Além disso, foram utilizadas para testes in vivo e in vitro com células de melanoma melanótico (B16F10) ou amelanótico (B16G4F). As células tumorais em cultura ou os tumores em camundongos C57BL6 foram irradiados com luz em 635 nm e os tumores foram observados por 15 dias após o tratamento. Houve evidente aumento na geração de oxigênio singlete por ambos fotossensibilizadores, e maior geração de radicais livres por parte do fotossensibilizador metilglucaminado. O oposto ocorre com o fotossensibilizador sem metilglucamina. Houve, também, moderada citotoxicidade no escuro quando células foram incubadas com nanopartículas recobertas por ftalocianinas ou não. Quando ativados pela luz, os complexos ftalocianinas-nanobastões desencadearam um aumento de 5ºC no meio de cultura das células, e a morte celular observada foi extensa (91% para a linhagem B16G4F e 95% para a linhagem B16F10). Tanto os resultados in vitro quanto os in vivo indicam que as propriedades das ftalocianinas testadas são melhoradas significativamente quando elas estão complexadas aos nanobastões. Este é um estudo pioneiro por utilizar duas porfirinas tetrassulfonadas específicas e por utilizar o mesmo comprimento de onda para a ativação dos fotossensibilizadores e nanobastões. / Studies with hyperthermic tumor ablation using metallic nanoparticles have been performed on the last decades, and show promising results on tumor remission, sometimes achieving the complete cancer elimination. The same occurs regarding on treatments based on photodynamic activity of photosensitizer compounds. Studies indicate that those therapeutic interventions - hyperthermic therapy using gold nanorods and photodynamic activity with many photosensitizers - together can present a synergistic effect, and offer a great therapeutic potential, although more investigation needs to be performed before such approach could be implemented. We proposed to investigate the effect of the attachment of photosensitizers onto the surface of gold nanorods (well-characterized devices for hyperthermia generation). After nanorods synthesis through a seed-mediated method, the PDT and hyperthermia\'s efficacy was assessed separately. The method used for covering the gold nanorods with photosensitizers did not permit, in a first approach, the attachment of porphyrins onto the nanoparticles surface, but the attachment of tetrasulfonated phthalocyanines was more successful. The phthalocyanine\'s degradation rate was assessed as an indirect parameter of singlet oxygen generation. After centrifuging and washing the nanoparticles, we saw that the photosensitizers do not keep attached to the nanorods. On a second approach, we chose to recover the nanorods with two zinc phthalocyanines - with or without methyl-glucamine groups. After the recovering process, the phthalocyanines formed ionic complexes with the CTAB that is previously recovering the nanoparticles. The nanorod-phthalocyanines complexes were analyzed by TEM, and their singlet oxygen and hydroxyl radical generation yield were assessed. Furthermore, they were tested in vitro in melanoticB16F10 and amelanotic B16G4F melanoma cells, and in vivo. The tumor cells (in vitro) and the tumor tissue (in vivo) with nanoparticles were irradiated with laser (at 635 nm), and the tumor growth in mice was observed for 15 days after the laser irradiation. It is evident the increase in the singlet oxygen generation, and higher HPF activation for the glucaminated Pc, but the inverse for the other photosensitizer. It seems like there is a type I to type II switch on the action mechanism of the latter Pc. A mild cytoxocity was observed with the nanorods conjugated with photosensitizer in the dark, but when they are activated by light (and taken into account a 5ºC rise in the temperature because of the surface plasmon resonance from the gold nanorods), the cell killing is intense (91% for B16G4F cell line, and 95% for B16F10 cell line). Both in vitro and in vivo results indicate that the photodynamic properties of the phthalocyanines tested are enhanced when they are attached onto the nanorods surface. This is a novel study because we used two tetrasulfonated phthalocyanines and because we used the same wavelength to activate both the nanorods and the photosensitizers.