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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

PURIFICATION, CHEMISTRY AND APPLICATION OF CARBON NANOTUBES

Hu, Hui 01 January 2004 (has links)
Purification, chemistry and application are three very important aspects of current research on carbon nanotubes (CNTs). In the dissertation, the purification of nitric acid treated single-walled carbon nanotubes (SWNTs), the dissolution and dichlorocarbene addition of SWNTs, and the effects of chemically functionalized CNTs on neuronal growth are discussed.The nitric acid treated SWNTs were purified by chemical treatment, cross-flow filtration, and centrifugation methods. The effects of nitric acid treatment on the SWNTs and the efficiency of different purification methods was evaluated by the measurement of purify of SWNTs via solution phase NIR. Nitric acid reflux followed with controlled pH centrifugation can produce SWNTs with high purity. This purification mechanism was explained by the relationship of the concentration of the acidic sites on SWNTs and the zeta potential of SWNTs.The dissolution of SWNTs was achieved via chemical functionalization of SWNTs with octadecylamine (ODA). Dichlorocarbene addition to the sidewall of both ODA functionalized and as-prepared SWNTs was investigated. ODA functionalized HiPco-SWNTs were found to have the highest functionality of dichlorocarbene. Vis-NIR spectra of the dichlorocarbene functionalized SWNTs showed a significant decrease in the interband transitions of the semiconducting SWNTs, which indicated that the chemical functionalization of the sidewall of SWNTs changes the electronic properties of SWNTs. Far-IR spectra of the dichlorocarbene functionalized SWNTs showed a dramatic decrease in the electronic transitions at the Fermi level of metallic SWNTs, which was opposite to the effect of ionic doping by bromine. This difference in the far-IR spectroscopy can be used to distinguish covalent chemical functionalization and ionic doping effects of SWNTs.Chemically functionalized multi-walled carbon nanotubes (MWNTs) were applied as substrates for neuronal growth. By manipulating the charge carried by functionalized MWNTs we are able to control the outgrowth and branching pattern of neuronal processes. Chemically functionalized water soluble SWNTs graft copolymers were used in the modulation of outgrowth of neuronal processes. The graft copolymers were prepared by the functionalization of SWNTs with poly-m-aminobenzene sulphonic acid and poly-ethylene glycol. These functionalized water soluble SWNTs were able to increase the length of selected neuronal processes after their addition to the culturing medium.
2

FUNCTIONALIZATION OF SINGLE WALL CARBON NANOTUBES USING RF-PLASMA: THE ROLE OF DEFECTS IN SIDEWALL FUNCTIONALIZATION

JAYASINGHE, CHAMINDA 05 October 2007 (has links)
No description available.
3

Espectroscopia Raman ressonante em nanotubos de carbono funcionalizados / Resonant Raman Spectroscopy in carbon nanotubes functionalized

Saraiva, Gilberto Dantas January 2008 (has links)
SARAIVA, Gilberto Dantas. Espectroscopia Raman ressonante em nanotubos de carbono funcionalizados. 2008. 145 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2008. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-05-04T19:13:31Z No. of bitstreams: 1 2008_tese_gdsaraiva.pdf: 6765379 bytes, checksum: ded06cc237d77dabfc5886e3ed738be4 (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-05-07T14:32:02Z (GMT) No. of bitstreams: 1 2008_tese_gdsaraiva.pdf: 6765379 bytes, checksum: ded06cc237d77dabfc5886e3ed738be4 (MD5) / Made available in DSpace on 2015-05-07T14:32:02Z (GMT). No. of bitstreams: 1 2008_tese_gdsaraiva.pdf: 6765379 bytes, checksum: ded06cc237d77dabfc5886e3ed738be4 (MD5) Previous issue date: 2008 / In this Thesis we report a study of the synthesis and functionalization of carbon nanotubes. Regarding the synthesis, we produced carbon nanotubes samples using the chemical vapor deposition method. Both single-wall and multi-wall carbon nanotubes were produced. The basic difference between these two growth results was the catalyst employed. We also have changed the exposure time of catalyst particle to the hydrogen gas to find out the optimal parameters for growing the nanotubes. The obtained samples were characterized by resonance Raman spectroscopy and thermal analysis. The obtained samples show higher thermal stability compared with some commercially available samples. Regarding functionalization of the tubes we studied three different systems. Firstly, we investigated the effect of Si+ and C+ ions bombardment on the structural and electronic properties of highly pure double wall carbon nanotubes (DWNTs). The implantation was performed at room temperature with high fluencies of ions varying from 1 to 100 x( 10 13 ions/cm2) and the Raman spectroscopy was the main technique employed for studying the ion implantation-induced changes in the nanotubes. The effects of the Si+ implantation is stronger than that of C+ and this is attributed to the larger ionic radius of Si. The D to G band intensity ratio was used for probing the ion concentration for which the system looses its sp2 character leading to a highly disordered system with a high concentration of sp3 bonds. We observed that as the ion implantation dosage increases, the D-band intensity increases and the radial breathing modes (RBM) of the semiconducting (outer) and metallic (outer) tube disappear first, before from the inner tubes. At higher ion-implantation dosage, the carbon nanotubes are completely deformed and the Raman spectrum is typical of highly disordered graphite. Secondly, we investigated the effects of H2SO4 doping on DWNTs and SWNTs where the diameter of SWNTs are in the same range as the inner tube of the DWNTs. The comparison of these two systems allow to further improve the knowledge of doping effects on the constituents of DWNTs as well as to establish differences between the exohedral doping of SWNTs and DWNTs bundles. Upon doping with H2SO4 the Breit-Wigner-Fano lineshape of metallic tubes in the SWNTs samples decreases and the G band frequencies increase thus indicating that an electronic charge transfer is occurring from the nanotubes to the dopant molecule. The effect on the DWNTs is opposite to that of SWNTs thus evidencing that the inner and outer shell interaction seems to affect the inner tube electronic transitions more than those of the outer tubes. Thirdly, we report a detailed characterization of a novel carbon nanotube-based system that is a coaxial nanocable made of carbon as core and selenium as shell. Carbon nanotube bundles are wrapped up within a trigonal selenium shell. We have demonstrated that the Butyl-lithium compound plays an important role in promoting the interaction between the carbon nanotubes and the selenium shells and thus enables the preparation of these nanocable structures. The Raman spectra of the SWNTs in the residue and the Se-CNT nanocables suggests that this selenium-carbon interaction is stronger for semiconducting nanotubes than for metallic nanotubes. The chemistry of Selenium would allow the synthesis of carbon nanotubes decorated with other functional Se-based structures, such as CdSe, ZnSe, among others. / Esta tese consiste no estudo do processo de síntese e funcionalização de nanotubos de carbono. A síntese dos nanotubos de carbono foi realizada usando a técnica de deposição química a partir da fase vapor (CVD). Foram sintetizados Nanotubos de parede simples (SWNTs) e múltipas (MWNTs) . A diferença básica das metodologias usadas para preparar as amostras foi o uso de diferentes catalisadores expostos ao gás hidrogênio por diferentes intervalos de tempo. As amostras obtidas foram caracterizadas por espectroscopia Raman ressonante e análise térmica. Os resultados de análise térmica mostraram que as amostras sintetizadas apresentam uma excelente estabilidade térmica, quando comparada com algumas amostras disponíveis no mercado. Foram estudados três diferentes sistemas em relação ao processo de funcionalização de nanotubos de carbono. No primeiro sistema, investigamos o efeito da irradiação de íons de silício (Si+) e carbono (C+) nas propriedades eletrônicas e estruturais dos nanotubos de parede dupla (DWNTs). A implantação foi realizada à temperatura ambiente com concentrações de íons que variam de 1 a 100 x (1013 íons/cm2); e a espectroscopia Raman ressonante foi a principal técnica utilizada para estudar os efeitos da implantação. Os efeitos da implantação dos íons de Si+ na estrutura dos nanotubos são mais fortes do que os íons de C+ o que é atríbuido ao maior raio iônico do Si+. A razão das intensidades das bandas D e G foi usada para investigar a concentração de íons para a qual o sistema perde a característica sp2, deixando o sistema muito desordenado e com grande concentrações de ligações sp3. Observamos que o aumento da dosagem de íons aumenta a intensidade da banda D e os modos radiais de respiração dos nanotubos semicondutores (tubo externo) e metálicos (tubo externos) desaparecem primeiramente do que os tubos internos. Para altas dosagens de implantação de íons de silício ou carbono observamos que os nanotubos são completamente deformados e os espectros Raman apresentam aspectos de grafite altamente desordenados. No segundo sistema estudado, investigamos os efeitos da dopagem da molécula de H2SO4 nos SWNTs e DWNTs com distribuição de diâmetros dos SWNTs similar aos tubos internos dos DWNTs. A comparação destes dois sistemas permitiu ter um maior conhecimento dos efeitos da molécula H2SO4 nos sistemas DWNTs como também estabelecer diferenças entre a dopagem por intercalação nos feixes de SWNTs e DWNTs. A dopagem com H2SO4 torna o perfil Breit-Wigner-Fano (BWF) dos nanotubos metálicos nos sistemas SWNTs menos acentuado e a freqüência da banda G aumenta indicando que uma transferência de carga ocorre dos nanotubos para as moléculas de H2SO4. O efeito nos DWNTs é o oposto ao que foi evidenciado para os SWNTs, mostrando que a interação entre os tubos internos e externos no sistema DWNTs parece afetar mais fortemente as transições eletrônicas dos tubos internos do que as transições dos tubos externos. No terceiro sistema estudado, caracterizamos de maneira detalhada um novo sistema híbrido baseado em nanotubos de carbono que consiste de um cabo coaxial com carbono no interior e uma casca de selênio como tubo exterior. Demonstramos que o composto Butil-Lítio promove a interação entre os nanotubos de carbono e a casca de selênio levando a formação destes nanocabos. O espectro Raman dos SWNTs da amostra resíduo e selênio-nanotubos sugere que os nanocabos de selênio carbono interagem mais fortemente com os nanotubos semicondutores do que com os nanotubos metálicos. Estimamos que a química do selênio permitirá sintetizar nanocabos de selênio-carbono decorados com outros compostos funcionais tais como CdSe, ZnSe entre outros.
4

Espectroscopia Raman ressonante em nanotubos de carbono funcionalizados. / Resonant Raman Spectroscopy in carbon nanotubes functionalized

Gilberto Dantas Saraiva 24 June 2008 (has links)
Esta tese consiste no estudo do processo de sÃntese e funcionalizaÃÃo de nanotubos de carbono. A sÃntese dos nanotubos de carbono foi realizada usando a tÃcnica de deposiÃÃo quÃmica a partir da fase vapor (CVD). Foram sintetizados Nanotubos de parede simples (SWNTs) e mÃltipas (MWNTs) . A diferenÃa bÃsica das metodologias usadas para preparar as amostras foi o uso de diferentes catalisadores expostos ao gÃs hidrogÃnio por diferentes intervalos de tempo. As amostras obtidas foram caracterizadas por espectroscopia Raman ressonante e anÃlise tÃrmica. Os resultados de anÃlise tÃrmica mostraram que as amostras sintetizadas apresentam uma excelente estabilidade tÃrmica, quando comparada com algumas amostras disponÃveis no mercado. Foram estudados trÃs diferentes sistemas em relaÃÃo ao processo de funcionalizaÃÃo de nanotubos de carbono. No primeiro sistema, investigamos o efeito da irradiaÃÃo de Ãons de silÃcio (Si+) e carbono (C+) nas propriedades eletrÃnicas e estruturais dos nanotubos de parede dupla (DWNTs). A implantaÃÃo foi realizada à temperatura ambiente com concentraÃÃes de Ãons que variam de 1 a 100 x (1013 Ãons/cm2); e a espectroscopia Raman ressonante foi a principal tÃcnica utilizada para estudar os efeitos da implantaÃÃo. Os efeitos da implantaÃÃo dos Ãons de Si+ na estrutura dos nanotubos sÃo mais fortes do que os Ãons de C+ o que à atrÃbuido ao maior raio iÃnico do Si+. A razÃo das intensidades das bandas D e G foi usada para investigar a concentraÃÃo de Ãons para a qual o sistema perde a caracterÃstica sp2, deixando o sistema muito desordenado e com grande concentraÃÃes de ligaÃÃes sp3. Observamos que o aumento da dosagem de Ãons aumenta a intensidade da banda D e os modos radiais de respiraÃÃo dos nanotubos semicondutores (tubo externo) e metÃlicos (tubo externos) desaparecem primeiramente do que os tubos internos. Para altas dosagens de implantaÃÃo de Ãons de silÃcio ou carbono observamos que os nanotubos sÃo completamente deformados e os espectros Raman apresentam aspectos de grafite altamente desordenados. No segundo sistema estudado, investigamos os efeitos da dopagem da molÃcula de H2SO4 nos SWNTs e DWNTs com distribuiÃÃo de diÃmetros dos SWNTs similar aos tubos internos dos DWNTs. A comparaÃÃo destes dois sistemas permitiu ter um maior conhecimento dos efeitos da molÃcula H2SO4 nos sistemas DWNTs como tambÃm estabelecer diferenÃas entre a dopagem por intercalaÃÃo nos feixes de SWNTs e DWNTs. A dopagem com H2SO4 torna o perfil Breit-Wigner-Fano (BWF) dos nanotubos metÃlicos nos sistemas SWNTs menos acentuado e a freqÃÃncia da banda G aumenta indicando que uma transferÃncia de carga ocorre dos nanotubos para as molÃculas de H2SO4. O efeito nos DWNTs à o oposto ao que foi evidenciado para os SWNTs, mostrando que a interaÃÃo entre os tubos internos e externos no sistema DWNTs parece afetar mais fortemente as transiÃÃes eletrÃnicas dos tubos internos do que as transiÃÃes dos tubos externos. No terceiro sistema estudado, caracterizamos de maneira detalhada um novo sistema hÃbrido baseado em nanotubos de carbono que consiste de um cabo coaxial com carbono no interior e uma casca de selÃnio como tubo exterior. Demonstramos que o composto Butil-LÃtio promove a interaÃÃo entre os nanotubos de carbono e a casca de selÃnio levando a formaÃÃo destes nanocabos. O espectro Raman dos SWNTs da amostra resÃduo e selÃnio-nanotubos sugere que os nanocabos de selÃnio carbono interagem mais fortemente com os nanotubos semicondutores do que com os nanotubos metÃlicos. Estimamos que a quÃmica do selÃnio permitirà sintetizar nanocabos de selÃnio-carbono decorados com outros compostos funcionais tais como CdSe, ZnSe entre outros. / In this Thesis we report a study of the synthesis and functionalization of carbon nanotubes. Regarding the synthesis, we produced carbon nanotubes samples using the chemical vapor deposition method. Both single-wall and multi-wall carbon nanotubes were produced. The basic difference between these two growth results was the catalyst employed. We also have changed the exposure time of catalyst particle to the hydrogen gas to find out the optimal parameters for growing the nanotubes. The obtained samples were characterized by resonance Raman spectroscopy and thermal analysis. The obtained samples show higher thermal stability compared with some commercially available samples. Regarding functionalization of the tubes we studied three different systems. Firstly, we investigated the effect of Si+ and C+ ions bombardment on the structural and electronic properties of highly pure double wall carbon nanotubes (DWNTs). The implantation was performed at room temperature with high fluencies of ions varying from 1 to 100 x( 10 13 ions/cm2) and the Raman spectroscopy was the main technique employed for studying the ion implantation-induced changes in the nanotubes. The effects of the Si+ implantation is stronger than that of C+ and this is attributed to the larger ionic radius of Si. The D to G band intensity ratio was used for probing the ion concentration for which the system looses its sp2 character leading to a highly disordered system with a high concentration of sp3 bonds. We observed that as the ion implantation dosage increases, the D-band intensity increases and the radial breathing modes (RBM) of the semiconducting (outer) and metallic (outer) tube disappear first, before from the inner tubes. At higher ion-implantation dosage, the carbon nanotubes are completely deformed and the Raman spectrum is typical of highly disordered graphite. Secondly, we investigated the effects of H2SO4 doping on DWNTs and SWNTs where the diameter of SWNTs are in the same range as the inner tube of the DWNTs. The comparison of these two systems allow to further improve the knowledge of doping effects on the constituents of DWNTs as well as to establish differences between the exohedral doping of SWNTs and DWNTs bundles. Upon doping with H2SO4 the Breit-Wigner-Fano lineshape of metallic tubes in the SWNTs samples decreases and the G band frequencies increase thus indicating that an electronic charge transfer is occurring from the nanotubes to the dopant molecule. The effect on the DWNTs is opposite to that of SWNTs thus evidencing that the inner and outer shell interaction seems to affect the inner tube electronic transitions more than those of the outer tubes. Thirdly, we report a detailed characterization of a novel carbon nanotube-based system that is a coaxial nanocable made of carbon as core and selenium as shell. Carbon nanotube bundles are wrapped up within a trigonal selenium shell. We have demonstrated that the Butyl-lithium compound plays an important role in promoting the interaction between the carbon nanotubes and the selenium shells and thus enables the preparation of these nanocable structures. The Raman spectra of the SWNTs in the residue and the Se-CNT nanocables suggests that this selenium-carbon interaction is stronger for semiconducting nanotubes than for metallic nanotubes. The chemistry of Selenium would allow the synthesis of carbon nanotubes decorated with other functional Se-based structures, such as CdSe, ZnSe, among others.
5

Spectroscopic Studies of Carbon Nanotubes

Zhang, Ru 25 April 2008 (has links)
No description available.
6

Development of single wall carbon nanotube transparent conductive electrodes for organic electronics

Jackson, Roderick Kinte' 22 June 2009 (has links)
Organic electronic devices are receiving growing interest because of their potential to employ lightweight, low-cost materials in a flexible architecture. Typically, indium tin oxide (ITO) is utilized as the transparent positive electrode in these devices due to its combination of high transmission in the visible spectrum and high electrical conductivity. However, ITO may ultimately hinder the full market integration of organic electronics due to its increasing cost, the limited availability of indium, lack of mechanical flexibility, and sustainability with regards to the environment and material utilization. Therefore, alternatives for ITO in organic electronics are currently being pursued. Transparent electrodes comprised of single wall carbon nanotubes (SWNTs) are an appealing choice as a surrogate because of the extraordinary electrical and mechanical properties these 1-D structures posses. As such, the research presented in this dissertation has been conducted to advance the goal of manufacturing SWNT networks with transparent electrode properties that meet or exceed those of ITO. To this end, SWNT films were characterized with regard to the collective and individual optoelectronic properties of the SWNTs that comprise the network. Specifically, corroborative theoretical and experimental observations were employed to expand the understanding of how the optoelectronic properties of polydisperse and monodisperse SWNT networks are enhanced and sustained through chemical treatment and subsequent processing. In addition, the impact of interfacial electrical contact resistance between SWNT electrodes and metallic fingers often used in photovoltaic system applications was elucidated. In summary, the research presented in this dissertation can be leveraged with present state of the art in SWNT films to facilitate future SWNT electrode development.
7

Investigations Of Graphene And Open-Framework Metal Carboxylates

Ghosh, Anupama 09 1900 (has links) (PDF)
The thesis contains two parts. Part 1 describes the investigations on graphene and contains five sections. Section 1, gives a brief overview of graphene and other nanocarbons. The other four sections deal with various aspects of single-layer and few-layer graphene such as functionalization and solubilization, surface properties and gas adsorption, molecular charge transfer interaction and some properties and applications. Section 2 describes covalent and noncovalent functionalization and solubilization of few-layer graphene samples prepared by different methods as well as of single-walled carbon nanotubes (SWNTs). It includes covalent functionalization of graphene with organometallic reagents, noncovalent functionalization of graphene and SWNTs with surfactants as well as large aromatic molecules, and exfoliation of few-layer graphene by a water-soluble coronene carboxylate. Section 3 deals with surface properties and gas adsorption (mainly H2 and CO2) of few-layer graphenes. It is found that graphene samples with high surface area can adsorb even more than 3 wt% of H2 at high pressure which makes it promising material for gas-storage applications. Section 4 describes the molecular charge-transfer interaction of single and few-layered graphenes and SWNTs with different electron-donor and -acceptor molecules probed by both ITC measurements and Raman spectroscopy. Electron–acceptor molecules interact more strongly with graphene and SWNTs than the -donor molecules and nature of interaction of metallic SWNTs are different than the as-prepared ones. A Raman study of the interaction of single-layer graphene, prepared by micromechanical cleavage as well as chemical route, with an electron donor molecule such as tetrathiofulvalene (TTF) and an electron acceptor molecule such as tetracyanoethylene (TCNE) is examined. In Section 5, some properties and applications of graphene are discussed. These include fluorescence quenching phenomena observed with few-layer graphene samples on two fluorescent molecules such as coronene and perylene derivatives. Fabrication of a sensing device as well as of FETs prepared from doped and undoped few-layer and single-layer graphene samples forms part of this section. Part 2 of the thesis includes a brief introduction of hybrid open-framework material and synthesis, characterization and crystal structure of various open-framework metal carboxylates, starting with different transition and main group metals. The carboxylic acids used to form these frameworks vary such as simple aliphatic amino acids such as beta-alanine and aspartic acid or simple aliphatic hydroxyl carboxylic acid such as malic acid in its chiral and achiral forms or five-membered heterocyclic aromatic acid, such as imidazole dicarboxylic acid.
8

Investigation Of Inorganic Nanomaterials & Polymer Films

Ghosh, Sandeep 01 1900 (has links) (PDF)
The thesis is divided into two parts. The first part deals with the research work carried out on the synthesis and chemical modification of nanomaterials whereas the second part describes the preparation and characterisation of polymer films and their use as separation membranes. Part I of the thesis describing the synthetic strategies and chemical manipulation schemes employed on various types of nanomaterials is divided into six chapters. Chapter 1 describes a chemist’s approach towards synthesizing and tuning the properties of different classes of nanomaterials along with a brief account of their potential applications. Chapter 2 of the thesis describes the synthesis and characterization of various metal nanostructures (viz. nanoparticles, nanorods, nanosheets etc.) of nickel, ruthenium, rhodium and iridium using a solvothermal procedure. Chapter 3 deals with the nanoparticles of the novel oxide metal ReO3. ReO3@Au, ReO3@Ag, ReO3@SiO2 and ReO3@TiO2 core-shell nanostructures with ReO3 as the core nanoparticle have been synthesized through a two-step process and characterized. Dependence of the plasmon band of the ReO3 nanoparticles on the interparticle separation has been examined by incorporating the nanoparticles in various polymer matrices and the results compared with those obtained with gold nanoparticles. Chapter 4 presents the dispersion of nanostructures of metal oxides such as TiO2, Fe3O4 and ZnO in solvents of differing polarity (water, DMF and toluene) in the presence of several surfactants. In Chapter 5 of the thesis, fluorous chemical method of separation of metallic and semiconducting single-walled carbon nanotubes is described. This method involves the selective reaction of the diazonium salt of a fluorous aniline with the metallic nanotubes in an aqueous medium and subsequent extraction of the same in a fluorous solvent leaving the semiconducting nanotubes in the aqueous layer. Chapter 6 presents the studies on the interaction of single walled nanotubes and graphene with various halogen molecules (I2, IBr, ICl and Br2) of varying electron affinity probed by employing Raman spectroscopy and electronic absorption spectroscopy. Part II of the thesis describes a general method of fabricating ultrathin free-standing cross-linked polymer films and their subsequent use as separation membranes. A particular class of 1-D nanomaterials namely cadmium hydroxide nanostrands were used in this method throughout, to generate a sacrificial layer upon which the polymer films were generated.
9

Synthèse par « Click Chemistry » de matériaux hybrides et éudes de leurs assemblages supramoléculaires / Synthesis of hybrid materials via "click-chemistry" and studies of their supramolecular assemblies

Le ho, Khanh hy 15 November 2012 (has links)
L’approche « bottum-up » via l’auto-assemblage moléculaire est considéré comme une voie prometteuse pour contrôler la fabrication de nouveaux matériaux et leur intégration dans des dispositifs hybrides présentant de propriétés nouvelles. Dans ce travail, nous avons synthétisé plusieurs hybrides à base de molécules organiques (fullerène, porphyrines, phtalocyanine), d’oligonucléotides ou de nanotubes de carbone.Dans un premier temps, nous nous sommes intéressés à la synthèse d’une nouvelle famille de produits constituée d’une unité C60 lié à deux chromophores positionnés face à face et permettant la formation de complexes hôte-invités. Nous avons montré que ces composés s’assemblent pour donner des structures supramoléculaires en solution et sur surface. Les interactions électroniques et la compléxation entre le fullerène et les deux chromophores (porphyrines et phtalocyanines) ont été étudiées par spectroscopie optique et RMN ainsi que par voltammétrie cyclique.Parmi les outils de l’approche « bottom-up », l’ADN a montré son extraordinaire potentiel pour la fabrication d’assemblages bio-dirigés. En effet, la synthèse de matériaux hybrides à base d’ADN permet un contrôle précis (théoriquement à l’échelle d’une base, ~3,4Å) du positionnement des groupements fonctionnels dans un matériau. Dans le but de former des réseaux bi- et tridimensionnels à base d’ADN permettant le positionnement de nano-objets, nous avons synthétisé des hybrides à base d’oligonucléotides et de porphyrines (molécule 2D) ou d’adamantane (molécule 3D). Des édifices supramoléculaires simples ont été réalisés et le travail se poursuit en vue de la réalisation de réseaux fonctionnels.Enfin, dans une dernière partie, nous nous sommes intéressés à la fonctionnalisation des nanotubes de carbone monoparoi (SWNT) avec des chromophores de type porphyrines et phtalocyanines. Alors que les porphyrines présentent une absorption intense presque exclusivement dans le bleu, les phtalocyanines absorbent principalement dans le rouge. Combiner ces deux chromophores à la surface des nanotubes de carbone présente donc un intérêt particulier pour la collecte de lumière car les deux composés absorbent des régions complémentaires du spectre visible. Ce travail ouvre la voie vers l'étude des propriétés optoélectroniques des hybrides à base de nanotubes et en particulier leur utilisation pour la conversion d’énergie lumineuse en énergie électrique (application photovoltaïque). / An Approach "bottum-up" via molecular self-assembly is considered as a promising way to control the manufacture of new materials and their integration into hybrid devices with novel properties. In this work, we have synthesized several hybrids based on organic molecules (fullerene, porphyrin, phthalocyanine), oligonucleotides or carbon nanotubes.At first, we were interested in the synthesis of a new family of products consisting of a unit C60 linked to two chromophores positioned face to face and allowing the formation of host-guest complexes. We have shown that these compounds are combined to give supramolecular structures in solution and on the surface. Electronic interactions and complexation between fullerene and the two chromophores (porphyrins and phthalocyanines) were studied by NMR and optical spectroscopy as well as cyclic voltammetry.Among the tools of the "bottom-up", DNA showed its tremendous potential for the production of bio-directed assembly. Indeed, the synthesis of hybrid materials based DNA allows precise control (theoretically on the scale of a base, ~ 3.4 Å) of the positioning of the functional groups in a material. In order to form networks and bi-dimensional DNA-based for positioning nano-objects, we have synthesized hybrid oligonucleotide-based and porphyrin molecule (2D) or adamantane molecule (3D). Supramolecular structures have been made and this work is ongoing to achieve functional networks.Finally, in a last part, we are interested in the functionalization of single-walled carbon nanotubes (SWNTs) with chromophores like porphyrins and phthalocyanines. While porphyrins exhibit almost exclusively an intense absorption in the blue (around 420-440 nm), phtalocyanines absorb mainly in the red spectral region. Taken together these two chromophores have interesting light harvesting, photophysical and redox properties; the two components will participate independently to increase the overall absorption in the visible range of the solar spectrum. This work opens the route to study the optoelectronic properties of hybrid nanotube and in particular their use for the conversion of light energy into electrical energy (photovoltaic application).

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