Orientador: Carlos Alberto Luengo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-22T18:52:15Z (GMT). No. of bitstreams: 1 Filizola_AlexandreRodrigues_M.pdf: 3632264 bytes, checksum: 03e1e31881e49ad653e27f6ff8d6fc88 (MD5) Previous issue date: 2013 / Resumo: O objetivo deste trabalho é o desenvolvimento e a caracterização de nanocatalisadores ativos na catálise heterogênea da obtenção de gás de síntese a partir de bio-óleos. Com este fim pretende-se utilizar nanotubos de carbono NTC como suportes tridimensionais para os metais catalíticos. A amostra obtida pelo método de arco elétrico automatizado foi caracterizada utilizando-se as técnicas de espectroscopia Raman, medidas de área superficial (BET) e distribuição de tamanho de poro (BJH), difração de Raios-X, medidas de magnetização SQUID e microscopia de transmissão eletrônica TEM. Espera-se que estes nanocatalisadores diminuam a temperatura do processo de gaseificação dos bio-óleos / Abstract: The aim of this thesis is the development and characterization of nanocatalysts for the heterogeneous conversion of bio-oils into synthesis gas. To this end we intend to use carbon nanotubes (NTC) as unconventional supports for the catalytic transition metals. The sample obtained by a computer controlled electric arc method was characterized using the techniques of Raman spectroscopy, surface area measurement (BET) and pore size distribution (BJH), X-ray diffraction, SQUID magnetization measurements and transmission electron microscopy TEM. It is expected that these nanocatalysts would reduce the temperature of the gasification process of the bio-oil samples / Mestrado / Física / Mestre em Física

Nanokomposit innehållande högdensitetspolyeten och kolnanorör återvanns och analyseradesför att undersöka hur materialets egenskaper påverkas av återvinning. Kompositenproducerades med 3 viktprocent kolnanorör och återvanns tio gånger genom att extrudera ochmala ner materialet. Analyser gjordes efter varje cykel av extrudering. Dessutom utfördessimulerade tester med kontinuerlig extrudering i 20, 100 och 200 minuter motsvarande 10, 50och 100 cykler. Därav kunde nedbrytningen av kompositen efter längre tids bearbetninganalyseras. I projektet studerades ett referensmaterial bestående av den rena polymeren för attkunna jämföra resultat. Karaktärisering av materialen för att bestämma mekaniska egenskapergjordes med dragprovning, böjningstest och slagprovning. För att undersöka termiskaegenskaper användes Differential Scanning Calorimetry (DSC) och Gel PermeationChromatography (GPC) användes för att hitta molekylviktsändringar. Fourier TransformInfrared Spectroscopy (FTIR) utfördes för att identifiera materialet. Resultaten visade ingenstörre skillnad i egenskaper efter tio återvinningscykler, vilket indikerade att materialet harförmåga att behålla sina egenskaper vid återvinning. I de simulerade cyklerna minskade denoxidativa induktionstiden efter 50 och 100 cykler, vilket berodde på att antioxidanterkonsumerats under bearbetningen. Efter 50 simulerade cykler hade molekylvikten börjat sjunkaoch efter 100 cykler kunde en signifikant minskning obseveras, vilket tydde på attpolymerkedjorna förkortats under bearbetningen. För kompositen däremot var molekylviktenstabil, på grund av att kolnanorören skyddade polymeren vid nedbrytning. / Nanocomposite containing High Density Polyethylene (HDPE) and Carbon Nanotubes (CNTs)was reprocessed and characterised to investigate the effect on properties during recycling. Thecomposite was prepared with 3 wt-% CNTs and was recycled ten times by alternatereprocessing and grinding and thereafter the material was characterised. Furthermore, simulatedcycles with continuous processing at 20, 100 and 200 minutes were conducted, representing 10,50 and 100 cycles respectively, in order to investigate the degradation after longer time ofprocessing. In both trials, a reference material containing neat HDPE was studied. Thecharacterisation of the materials produced was conducted using tensile, flexural and charpyimpact testing for investigation of mechanical properties. Differential Scanning Calorimetry(DSC) was used for determining the thermal behaviour and Gel Permeation Chromatography(GPC) to find molecular weight changes. Fourier Transform Infrared Spectroscopy (FTIR) wasused for identification of the material. The results showed no major difference in propertiesafter ten recycling steps, which indicated that the material had the ability to retain its propertiesduring recycling. In the simulated cycles, the oxidative induction time was decreased after 50and 100 cycles, meaning that antioxidants had been consumed during processing. After 50cycles the molecular weight for the reference material was slightly decreased and after 100cycles significantly decreased, indicating chain scission of the polymer chains. For thecomposite the molecular weight was stable, due to that the carbon nanotubes protect thepolymer matrix during degradation.

Abstract The main objective of this thesis is to study unique cases for computer-assisted finite element modeling (FEM) of thermal, mechanical and thermo-mechanical problems related to silicon and carbon. Computational modeling contributed to solve scientific problems either by validating the experimental results obtained earlier or by predicting the behavior of a particular system. In the model generation phase, emphasis is placed on simplification of a physical problem without loosing the validity or important details. As a consequence of reasonably reduced variables and also degrees of freedom of the elements in our models, the simulations could be performed using a commercial FEM software package, ANSYS®. To test the capabilities of the method (i) a steady-state finite element thermal analysis has been accomplished and verified by experiments for the case of laser-assisted heating of different materials. (ii) Mechanisms (Dember and Seebeck effects) responsible for the reduction of gold ions and deposition of metallic gold on p-type semiconductors from liquid precursors have been investigated by computing the surface temperature profiles of silicon wafers exposed to laser irradiation. (iii) Temperature field in a multi-component system caused by laser illumination was modeled to determine the heat affected zone in the case of laser soldering of flip-chips on transparent printed circuit board assemblies. (iv) Origin of the experimentally observed residual strain in thermally oxidized porous silicon structures was revealed by computing the strain fields in silicon-silicon oxide porous materials considering both intrinsic and thermal stress components. (v) Finally, we demonstrated that Joule heat generated on a silicon chip can be removed efficiently using micro-fin structures made from aligned carbon nanotubes. Computational fluid dynamics and thermal-electric finite element models were developed to study the steady-state laminar coolant flow and also the temperature distribution for the chips. The presented novel results have potential in silicon and carbon nanotube based technologies, including deeper understanding of the processes and problems in manufacturing electronic devices.

In the last decade, carbon nanotubes (CNTs) and Graphene nanoplatelets (GNPs) have attracted a lot of attentions in various polymeric and ceramic composite systems, in an effort to improve their mechanical and functional properties. Al2O3 has attracted considerable interests in ceramics community, in particular as a matrix material for composite fabrications. The high stiffness, excellent thermal stability and chemical resistance of Al2O3 make it practically a very important engineering material, and if we can overcome its brittleness issue, its applications will be much wider. Adding CNTs as a reinforcement to the Al2O3 matrix to improve the toughness is one of the most promising methods. Similarly, GNPs have recently also been shown to be very promising for the same purpose. It has been demonstrated that by adding a mixture of the 2D-GNPs and 1D-CNTs into a polymer matrix, the toughest or strongest man-made ropes have been made. However, the homogenous dispersion of CNTs or GNPs is more of a challenge in a ceramic matrix than in polymeric matrices, owing to the tendency of CNT agglomerations and more steps are needed to completely transfer the useful properties of CNTs and GNPs into ceramics. In this thesis, nanocomposites of Al2O3 reinforced with a hybrid of GNTs (a blend of GNPs and CNTs) were first fabricated. The hybrid GNT reinforcements were mixed with the Al2O3 using a wet chemical technique under ultrasonic treatment. The effects of varied GNT contents on the microstructural features and mechanical properties of the nanocomposites were then investigated. It is found that the well-dispersed GNT fillers resulted in high sintered densities (>99%) in the composites, whilst the fracture mode alteration, grain refinement and improved flexural strength of the composites are all associated with the inclusion of CNTs and GNPs. The average fracture toughness of the nanocomposites reached up to 5.7 MPa·m1/2, against 3.5 MPa·m1/2 of the plain Al2O3, and the flexural strength improved from 360 MPa to 424 MPa respectively, at a hybrid addition of 0.5 wt% GNPs and 1 wt% CNTs. The toughening mechanisms attributed with the unique morphologies and structures of the GNT fillers were also discussed based on analyses on the morphology, grain sizes and fracture mode. The effects of hot-pressing (HP) and spark plasma sintering (SPS) methods on the grain size, microstructural features, and mechanical behaviour of GNT-reinforced Al2O3 nanocomposites were then comprehensively studied. Identical overall reinforcement contents at various GNP/CNT ratios were selected to prepare the composites using both HP and SPS. Highly densified samples (>98%) were obtained at 1650°C under 40 MPa in Ar atmosphere, with dwell times of 1 h and 10 min for HP and SPS respectively. Both types of sample showed a mixture of inter- and trans-granular fracture behaviour. A 50% grain size reduction was observed for samples prepared by HP, compared with the SPS samples. Both types of samples achieved a high flexural strength and fracture toughness of > 400 MPa and 5.5 MPa·m1/2, respectively, whilst the properties of the SPS samples peaked at relatively lower GNT contents than those of the HP samples. Based on analyses of the morphology, grain sizes and fracture mode, similar toughening mechanisms for both types of sample were observed, involving the complex characteristics of the combined GNT fillers. The tribological performance of the HPed pure Al2O3 and its composites containing various hybrid GNT contents was further evaluated under different loading conditions using a ball-on-disc method. Benchmarked against the pure Al2O3, the composite reinforced with a 0.5 wt% GNP exhibited a 23% reduction in the friction coefficient along with a promising 70% wear rate reduction, and a hybrid reinforcement consisting of 0.3 wt.% GNPs + 1 wt.% CNTs resulted in even better performance, with a 86% reduction in the wear rate. The extent of damage to the reinforcement phases caused during wear was studied using Raman spectroscopy. The wear mechanisms for the composites were analysed according to the mechanical properties, brittleness index and microstructural characterization. The combination between GNPs and CNTs contributed to the excellent wear resistance properties for the hybrid GNT-reinforced composites. The GNPs played an important role in the formation of a tribofilm on the worn surface by exfoliation; whereas the CNTs contributed to the improvement in fracture toughness and prevented the grains being pulled out during the tribology test. Finally, Graphene Oxide (GO) was used to replace the GNPs in the hybrid, to prepare Al2O3-GONT nanocomposites, by adopting a new sol-gel processing, in addition to powder mixing. It has been found that sol-gel process leads to an impressive grain size reduction of 62%, the fracture toughness and flexural reached 6.2 MPa·m1/2 and 420 MPa (i.e. 70% and 14% improvement), respectively, than those of pure Al2O3, which even marginally outperformed the previously optimised Al2O3-GNP nanocomposites by 8% in fracture toughness. The success of our new sol-gel strategy opens up new opportunities for choosing hybrid reinforcements for the fabrication of advanced ceramic nanocomposites.

Ph.D. (Chemistry) / Please refer to full text to view abstract

This dissertation investigates the heterogeneous electron transfer dynamics and electrocatalytic behaviour of the following molecules immobilized on gold electrode: (a) 2-dimethylaminoethanethiol (DMAET), with and without integration with poly (m-aminobenzenesulfonic acid) functionalised single-walled carbon nanotubes (SWCNT-PABS); (b) SWCNT-PABS and iron (II) phthalocyanine nanoparticles (nanoFePc); (c) Colloidal gold / Gold nanoparticles (AuNP) and nanoFePc (d) ; water-soluble iron (II) tetrasulfophtalocyanine (FeTSPc) and SWCNT-PABS, and (e) novel monolayer protected gold nanoparticles (MPCAuNPs) by means of either (i) layer-by-layer (LBL) self-assembly or (ii) self-assembled monolayer (SAM) fabrication strategy. Atomic force microscopy and electrochemical studies (cyclic voltammetry, and electrochemical impedance spectroscopic) were used to monitor the substrate build-up, via strong electrostatic interaction. The surface pKa of DMAET was estimated at 7.6, smaller than its solution pKa of 10.8. It is also shown that SWCNT-PABS is irreversibly attached to the DMAET SAM. For layered films involving SWCNT-PABS and nanoFePc (Au-DMAET- SWCNT-PABS-nanoFePc) n (n=1-5 layers) as the number of bilayers increase, the electron transfer kinetics of the [Fe(CN) 6]3-/4 redox probe decreases. On the contrary, LBL assembly involving AuNP and nanoFePc (Au-DMAET-AuNP-nanoFePc) n (n=1-4 layers) shows an increase followed by a decrease in electron transfer kinetics subsequent to the adsorption of nanoFePc and AuNP layers, respectively. For SAMs involving FeTSPc and SWCNT-PABS, the mixed hybrid (Au-DMAET-SWCNT-PABS/FeTSPc) exhibited fastest charge transport compared to other electrodes. For the novel MPCAuNPs, the protecting or stabilizing ligands investigated were the (1-sulfanylundec-11-yl) tetraethylene glycol (PEG-OH) and the (1-sulfanylundec-11-yl) polyethylene glycolic acid (PEG-COOH). Three different mass percent ratios (PEG-COOH : PEG-OH), viz. 1:99 (MPCAuNP-COOH1%), 50:50 (MPCAuNP-COOH50%) and 99:1 (MPCAuNP-COOH99%) were used to protect the gold nanoparticles. The impact of these different ratios on the electron transfer dynamics in organic and aqueous media was explored. The average electron transfer rate constants (ket / s-1) in organic medium decreased as the concentration of the surface-exposed –COOH group in the protecting monolayer ligand increased: MPCAuNP-COOH1% (~ 10 s-1) > MPCAuNP-COOH50% (~ 9 s-1) > MPCAuNP-COOH99% (~ 1 s-1). In aqueous medium, the trend is reversed. This behaviour has been interpreted in terms of the hydrophobicity (quasi-solid nature) and hydrophilicity (quasi-liquid nature) of the terminal –OH and –COOH head groups, respectively. The ionization constants of the terminal groups (i.e., surface pKa) was estimated as ~ 8.2 for the MPCAuNP-COOH1%, while both MPCAuNP-COOH50% and MPCAuNP-COOH99% showed two pKa values of about 5.0 and ~ 8.0, further confirming the hydrophilicity / hydrophobicity of these surface functional groups. Hydrogen peroxide (H2O2), epinephrine (EP) and ascorbic acid (AA) were used as model analytes to examine electrocatalytic ability of these nanostructured assemblies. The electrochemical reduction of H2O2 at a constant concentration was amplified upon increasing bilayer formation of SWCNT-PABS and nanoFePc, while SWCNT-PABS/FeTSPc showed the best response towards the detection of epinephrine. MPCAuNP-COOH99% showed an excellent suppression of the voltammetric response of the AA and an enhanced electrocatalytic activity towards the detection of EP compared to the other MPCAuNPs. / Thesis (PhD)--University of Pretoria, 2010. / Chemistry / unrestricted

For the first time, new metallophthalocyanine (MPc) complexes: (i) nanostructured MPc (nanoMPc, where M = iron or cobalt); (ii) octabutylsulphonylphthalocyanine (MOBSPc, where M = iron or cobalt); and (iii) iron (II) tetrakis(diaquaplatinum)octacarboxyphthalocyanine (PtFeOCPc) were synthesized and characterized using advanced microscopic and spectroscopic techniques such as MS, AFM, HRTEM, FESEM, and EDX. Electrochemical techniques such as cyclic voltammetry, square wave voltammetry, chronoamperometry, rotating disk electrode, and electrochemical impedance spectroscopy, were used to explore the redox chemistry, heterogeneous electron transfer kinetics (HET), and electrocatalytic properties of these MPc complexes towards oxygen reduction reaction (ORR), oxidation of formic acid, thiocyanate and nitrite on a edge plane pyrolytic graphite electrode (EPPGE) platform pre-modified with or without acid functionalized multi-walled carbon nanotubes (MWCNTs). The MWCNT-MPc platforms exhibit enhanced electrochemical response in terms of (i) HET towards an outer-sphere redox probe ([Fe(CN)6]3-/[Fe(CN) 6]4-), and (ii) catalytic activities towards the investigated analytes. The MWCNTnanoMPc electrode exhibits faster HET constant (kapp ≈ 30 – 56 x 10-2 cms-1 compared to their bulk MPc counterparts (≈ 4 – 25 x 10-2 cms-1). The MWCNT-nanoMPc exhibited enhanced electrocatalytic properties (in terms of sensitivity and limit of detection, LoD) towards the detection of thiocyanate and nitrite in aqueous solutions. ORR was a 4- electron process with very low onset potential (-5 mV vs. Ag|AgCl saturated KCl). HET and ORR at MOBSPc complexes supported on MWCNTs showed that the MWCNT–MOBSPc exhibited larger Faradaic current responses than the electrodes without MWCNTs. The rate constant at the MWCNT-MOBSPc electrodes (kapp ≈ (22 – 37) x 10-2 cms-1) is about a magnitude higher than the electrodes without MWCNT (kapp ≈ (0.2 – 93) x 10-3 cms-1). The MWCNT–FeOBSPc electrode gave the best ORR activity involving a direct 4-electron mechanism with low onset potential (0.0 mV vs. Ag|AgCl saturated KCl). The onset potential is comparable and even much lower than recent reports. The HET and electrocatalytic properties of PtFeOCPc supported on a MWCNT platform (MWCNT-PtFeOCPc) gave enhanced electrochemical response in terms of (i) HET (kapp ≈ 78 x 10-2 cms-1), (ii) catalytic rate constant (kcat ≈ 41 cm3mol-1s-1) and (iii) tolerance towards CO poisoning during formic acid oxidation. The ORR activity is a direct 4-electron transfer process at a rate constant of 2.78 x 10-2 cms-1; with a very low onset potential approximately 0.0 mV vs. Ag|AgCl saturated KCl. The electrooxidation of formic acid at MWCNT-PtFeOCPc follows the preferred ‘direct pathway’. This work clearly proves that the MWCNT-MPcs hybrid exhibit enhanced electrochemical and electrocatalytic activities towards the selected analytes compared to the MPcs alone. Considering the ease of fabrication of these electrodes (drop-dry method), these nanocomposite materials are promising platform for potential application in sensing and cataly. / Thesis (PhD)--University of Pretoria, 2011. / Chemistry / unrestricted

In this work, a chemiresistor-type sensing platform based on aligned arrays of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) was developed. Our N-MWCNT based sensors can be made on both rigid and flexible substrates; they are small, have low power consumption and are suitable for highly efficient and reliable detection of different biomolecules and gases, at room temperature. The performance of these sensors was demonstrated for avian influenza virus (AIV) subtype H5N1 DNA sequences and toxic gases NO and NH3 at low concentrations. In our study, chemical vapor deposition (CVD) method was applied to synthesize vertically aligned nitrogen doped carbon nanotube arrays on a large area (> 1 cm2) on Si/SiO2 substrate using Fe/Al2O3 layer as a catalyst and a mixture of ethanol and acetonitrile as a C/N source. Especially, the diameter, length, nitrogen-doping concentration and morphology of the nanotubes were controllably tailored by adjusting the thickness of catalyst film, reaction duration and temperature as well as the amount of nitrogen-containing precursor. For integrating N-MWCNTs into chemiresistor devices, we developed a direct contact printing method for a dry, controllable and uniform transferring and positioning of the CVD-grown vertical nanotubes onto well-defined areas of various rigid and flexible substrates. After horizontally aligned N-MWCNT arrays were formed on a target substrate, interdigitated metallic microelectrodes with an interspacing of 3 µm were deposited perpendicular to the nanotube alignment direction to fabricate chemiresistor devices for biomolecule and gas sensing. This way, well-aligned nanotubes were laid across the Au/Cr interdigitated electrode fingers, had a strong adhesion with the electrodes and served as conducting channels bridging the electrodes. The N-MWCNT based chemiresistor device was applied as a label-free DNA sensor for a highly sensitive and fast detection of AIV subtype H5N1 DNA sequences. For this, the nanotubes were functionalized with probe DNA, which was non-covalently attached to sidewalls of the N-MWCNTs via π-π interaction. Such functionalized sensors were applied to quantitatively detect complementary DNA target with concentration ranging from 20 pM to 2 nM after 15 min incubation at room temperature. The sensors showed no response to non-complementary DNA target for concentrations up to 2 µM showing an excellent selectivity. Investigations on the efficient gas sensing of N-MWCNT-based chemiresistor of reducing/ oxidizing gases NH3 and NO were also reported in this work. The aim was to assess the possibility for N-MWCNTs to be applied as innovative sensing materials for room temperature gas sensing. N-MWCNTs with varying doping levels (N/C ratio of 5.6 to 9.3at%) were used as sensing materials and exposed to NH3 (1.5-1000 ppm) and NO (50-1000 ppm) for exploring and comparing their sensing performance. This study offered an effective route for further modification of CNTs according to various sensing application. Finally, our investigations showed a high potential of the developed N-MWCNT-based sensing platform for various applications ranging from environmental monitoring to point-of-care medical diagnostics.

In this work, structure/property relationships in polypropylene (PP) nanocomposites have been investigated for different nanofillers. Nanofillers of modified clay based on montmorillonite (MMT) and multi-wall carbon nanotubes (MWNTs) have been selected and incorporated to the PP matrix as either single nanofillers or hybrid nanofillers. Melt mixing via a twin screw extruder and further moulding by injection moulding have been used to prepare PP nanocomposites. Moreover, the dilution of MWNT masterbatch has been used to prepare PP/MWNT and PP/clay/MWNT nanocomposites. Three types of the PP nanocomposites have been obtained: PP/clay, PP/MWNT and PP/clay/MWNT nanocomposites. In all three types of the PP nanocomposites, α- and -PP crystals were observed in the wide angle X-ray diffraction (WAXD) patterns. Furthermore, the addition of nanofillers to the PP did not appear to affect the PP orientation. Slight PP orientation in the PP nanocomposites was shown in the two-dimensional X-ray diffraction (2D-XRD) patterns. Mixed clay layers were combined in the PP/clay and PP/clay/MWNT nanocomposites and investigated by WAXD as well as transmission electron microscopy (TEM). In addition, the aggregated and individual MWNTs were present in both the PP/MWNT and PP/clay/MWNT nanocomposites TEM images. A rough fracture surface with cracks was revealed from the scanning electron microscopy (SEM) images of the three types of PP nanocomposites. Polarized optical microscopy (POM) micrographs were taken at different temperatures during cooling in a hot stage and revealed the limitation of PP spherulite growth upon adding the nanofillers to the PP. The incorporation of nanofillers was found not to affect the glass transition temperature (Tg) of PP which investigated by dynamic mechanical analysis (DMA). However, the increase of both the peak melting temperature (Tm) and the peak crystallization temperature (Tc) of PP with adding the nanofillers was shown by differential scanning calorimetry (DSC) thermograms. In addition, the nanofillers also have been shown to act as nucleating agents. The thermal stability of PP in a nitrogen atmosphere was enhanced by the nanofillers when examined by thermogravimatric analysis (TGA). DMA and tensile testing were performed and showed that the nanofillers act as reinforcement for the PP. The distribution, orientation and deformation of MWNTs in the PP/MWNT and PP/clay/MWNT nanocomposites have been followed by Raman spectroscopy. Significant shifts of the Raman G'-band from the MWNTs was obtained during deformation of the MWNT nanocomposites and the hybrid clay/MWNT nanocomposites as the stress transfer from the PP matrix to the MWNTs has occurred. A correlation between calculated modulus from deformation and measured modulus from DMA and tensile testing has been found for PP/MWNT and PP/clay/MWNT nanocomposites. Finally, the PP nanocomposites have been considered for use in packaging applications.

Dans le domaine du photovoltaïque, les cellules hybrides organiques sont une des voies les plus prometteuses, notamment grâce aux propriétés de collection de lumière des molécules de type chromophore. Les nanotubes de carbone, quant à eux, sont des nano-objets quasi unidimensionnels qui présentent des propriétés de transport exceptionnelles. La réalisation d’un couplage important entre une molécule collectrice de lumière et un nanotube de carbone représente donc une voie importante à explorer. Ce travail de recherche est consacré à l’étude du transfert d’énergie dans les composés nanotubes de carbone/chromophore. Une nouvelle méthode de fonctionnalisation non covalente des nanotubes de carbone est présentée. Basée sur une suspension micellaire de nanotubes, cette méthode permet d’obtenir un fort taux de fonctionnalisation tout en préservant les propriétés intrinsèques des nanotubes. Le transfert d’énergie est mis en évidence sur les composés nanotube/porphyrine par des mesures d’excitation de la photoluminescence sur ensemble de nanotubes ainsi que sur objets uniques. L’évaluation du rendement quantique de transfert par trois méthodes indépendantes montre un couplage de l’ordre de 100% entre la molécule et le nanotube- et ce malgré la faiblesse des interactions entre orbitales «Pi» mises en jeu dans la fonctionnalisation non covalente. Le dernier volet de ce travail est consacré à des mesures d’anisotropie à l’échelle de l’objet unique permettant d’obtenir des informations quant à l’arrangement des molécules à la surface des nanotubes. / In the field of photovoltaic, hybrid organic solar cells are one of the most promising ways, especially due to the light collection properties of chromophore molecules. On the other hand, carbon nanotubes are quasi one-dimensional nano-objects showing exceptional transport properties. The achievement of a significant coupling between a light harvesting molecule and a carbon nanotube is an important route to explore. This research is dedicated to the study of energy transfer in carbon nanotube/chromophore compounds. A new method of non-covalent functionalization of carbon nanotubes is presented. Based on a micellar suspension of nanotubes, this method provides a high degree of functionalization while preserving the intrinsic properties of nanotubes. The energy transfer is shown in nanotube/porphyrin compounds by photoluminescence excitation spectroscopy on ensembles as well as at the single molecule scale. The evaluation of the quantum efficiency of the transfer by three independent methods shows a coupling of the order of 100% between the molecule and the nanotube, despite the weak interactions between “Pi” orbitals involved in the non-covalent functionalization. The final part of this work is dedicated to anisotropy measurements on single compounds to gain information on molecular arrangement on the surface of nanotubes.