89 research outputs found
Assemblage de complexes inorganiques sur nanotubes de carbone monoparoi (Applications à la spintronique moléculaire et à la photocatalyse)
La spintronique molĂ©culaire et la photocatalyse sont deux domaines en constante Ă©volution. Le premier s attache Ă exploiter la possibilitĂ© de coupler deux phĂ©nomĂšnes physiques, Ă savoir le transport d un flux de porteurs de charges et le spin de l Ă©lectron, tandis que le second se concentre sur l exaltation des propriĂ©tĂ©s chimiques de transfert d Ă©lectrons d une espĂšce donnĂ©e grĂące au phĂ©nomĂšne physique d irradiation lumineuse. Depuis quelques annĂ©es, les nanotubes de carbone ont suscitĂ© un grand intĂ©rĂȘt Ă la fois en tant que composant pour la spintronique molĂ©culaire, en raison de leur grande cohĂ©rence de spin, et en tant que support idĂ©al pour la catalyse molĂ©culaire, grĂące Ă leurs exceptionnelles propriĂ©tĂ©s Ă©lectroniques de surface. Au cours de ce travail de thĂšse, nous nous sommes attachĂ©s Ă concevoir des complexes inorganiques possĂ©dant des propriĂ©tĂ©s physiques, (magnĂ©tiques ou optiques) et des propriĂ©tĂ©s chimiques (permettant leur assemblage non-covalent sur des nanotubes de carbone monoparoi) de maniĂšre Ă former des adduits complexes inorganiques-nanotubes aux propriĂ©tĂ©s exploitables en spintronique molĂ©culaire et en photocatalyse. Les propriĂ©tĂ©s des complexes synthĂ©tisĂ©s ont Ă©tĂ© extensivement caractĂ©risĂ©es (Chapitre 2), et les plus prometteurs de ces composĂ©s ont Ă©tĂ© assemblĂ©s avec succĂšs sur les nanotubes de carbone (Chapitre 3), comme en attestent les mesures spectroscopiques rĂ©alisĂ©es. Enfin, les deux domaines d applications concernĂ©s par nos travaux faisant intervenir des phĂ©nomĂšnes de transport Ă©lectronique, des Ă©tudes spĂ©cifiques sur des dispositifs Ă©lectriques de type transistor Ă effet de champ dont le canal de conduction est constituĂ© de nanotubes de carbone ont Ă©tĂ© rĂ©alisĂ©es (Chapitre 4). Celles-ci mettent Ă chaque fois en Ă©vidence l existence d une communication Ă©lectronique entre les complexes inorganique et les nanotubes de carbone sur lesquels ils sont assemblĂ©s au sein des dispositifs. Bien qu au final un couplage entre les propriĂ©tĂ©s magnĂ©tiques des complexes synthĂ©tisĂ©s et les propriĂ©tĂ©s de transport des nanotubes n ait pas pu ĂȘtre mis en Ă©vidence, de nombreux phĂ©nomĂšnes inattendus et extrĂȘmement intĂ©ressants tels que des effets ambipolaires, des transferts de charge ou des ruptures de liaisons ont Ă©tĂ© observĂ©s. Par contre, un fort couplage opto-Ă©lectronique a pu ĂȘtre obtenu entre un complexe et le flux de porteurs de charge des dispositifs, ce qui s avĂšre ĂȘtre de trĂšs bon augure pour des futures applications en photocatalyse.Molecular spintronic and photocatalysis are two fields in constant evolution. While the first deals with the coupling of two physical properties, the flux of charge carriers and the spin of the electron, the second is focusing on the enhancement of the electron transfer of chemical species under light irradiation. Recently, there has been an increasing interest in carbon nanotubes as new components for molecular spintronics, since they possess high spin coherence, and as ideal materials for molecular catalysis, for their tremendous electronic surface properties. Our work consisted in conceiving inorganic complexes with both physical (magnetic or optic) and chemical (ability of realizing non covalent assembly on single-walled carbon nanotubes) properties, in order to create new nanotube-complex nanohybrids which could be exploited for molecular spintronics or photocatalysis applications. The properties of the synthesized complexes were extensively characterized (Chapter 2), and the most promising molecules were successfully assembled onto carbon nanotubes, as is proven by the spectroscopic measurement which were performed (Chapter 3). Finally, since both domains of applications we considered involve electronic transportation, specific studies were realized on field effect transistor devices with carbon nanotubes as the conduction channel (Chapter 4). They evidence strong electronic communications between the inorganic complexes and the carbon nanotubes onto which they are assembled in the devices. Even if in the end no coupling was observed between the magnetic properties of the inorganic complexes and the transport ones of the carbon nanotubes, numerous unexpected and very interesting phenomena such as ambipolar behavior, charge transfer effect or bond cleavage were evidenced. As for the optoelectronic coupling which was investigated for photocatalytic applications, a first step was made as the transport of the carbon nanotube field effect transistor devices onto which a complex was assembled shows a strong dependence with the applied light irradiation.PARIS11-SCD-Bib. Ă©lectronique (914719901) / SudocSudocFranceF
Excitation transfer and luminescence in porphyrin-carbon nanotube complexes
Functionalization of carbon nanotubes with hydrosoluble porphyrins (TPPS) is
achieved by "-stacking". The porphyrin/nanotube interaction is studied by
means of optical absorption, photoluminescence and photoluminescence excitation
spectroscopies. The main absorption line of the porphyrins adsorbed on
nanotubes exhibits a 120 meV red shift, which we ascribe to a flattening of the
molecule in order to optimize interactions. The porphyrin-nanotube
complex shows a strong quenching of the TPPS emission while the
photoluminescence intensity of the nanotubes is enhanced when the excitation
laser is in resonance with the porphyrin absorption band. This reveals an
efficient excitation transfer from the TPPS to the carbon nanotube
Electrical-field-induced structural change and charge transfer of lanthanide-salophen complexes assembled on carbon nanotube field effect transistor devices.
International audienceThe application of a negative gate voltage on a carbon nanotube ïŹeld eïŹect transistor decorated by a binuclear Tb(III) complex leads to the generation of a negatively charged mononuclear one, presenting an electron density transfer to the nanotube and ambipolar behaviour
Charge Transfer and Tunable Ambipolar Effect Induced by Assembly of Cu (II) Binuclear Complexes on Carbon Nanotube Field Effect Transistor Devices
International audienceAssembly of paramagnetic Cu2 complexes with a SchiïŹ base scaïŹold possessing extended electron delocalization together with a quasi-planar structure onto carbon nanotubes induces a diameter-selective charge transfer from the complex to the nanotubes leading to an interestingly large and tunable ambipolar eïŹect. We used complementary techniques such as electron paramagnetic resonance, absorption spectroscopy, and photoluminescence to ensure the success of the assembly process and the integrity of the complex in the nanohybrid. We carried out density functional theory type calculations to rationalize the experimental results,evidencing the selective enhanced interaction of the metal complexes with one type of nanotube
Light control of charge transfer and excitonic transitions in a carbon nanotube/porphyrin hybrid
Carbon nanotubeâchromophore hybrids are promising building blocks in order to obtain a controlled electro-optical transduction effect at the single nano-object level. In this work, a strong spectral selectivity of the electronic and the phononic response of a chromophore-coated single nanotube transistor is observed for which standard photogating cannot account. This paper investigates how light irradiation strongly modifies the coupling between molecules and nanotube within the hybrid by means of combined Raman diffusion and electron transport measurements. Moreover, a nonconventional Raman enhancement effect is observed when light irradiation is on the absorption range of the grafted molecule. Finally, this paper shows how the dynamics of single electron tunneling in the device at low temperature is strongly modified by molecular photoexcitation. Both effects will be discussed in terms of photoinduced excitons coupled to electronic levels
Pulmonary arterial hypertension in adult onset Stillâs disease: a case report of a severe complication
Assemblage de complexes inorganiques sur nanotubes de carbone monoparoi : Applications à la spintronique moléculaire et à la photocatalyse
Molecular spintronic and photocatalysis are two fields in constant evolution. While the first deals with the coupling of two physical properties, the flux of charge carriers and the spin of the electron, the second is focusing on the enhancement of the electron transfer of chemical species under light irradiation. Recently, there has been an increasing interest in carbon nanotubes as new components for molecular spintronics, since they possess high spin coherence, and as ideal materials for molecular catalysis, for their tremendous electronic surface properties. Our work consisted in conceiving inorganic complexes with both physical (magnetic or optic) and chemical (ability of realizing non covalent assembly on single-walled carbon nanotubes) properties, in order to create new nanotube-complex nanohybrids which could be exploited for molecular spintronics or photocatalysis applications. The properties of the synthesized complexes were extensively characterized (Chapter 2), and the most promising molecules were successfully assembled onto carbon nanotubes, as is proven by the spectroscopic measurement which were performed (Chapter 3). Finally, since both domains of applications we considered involve electronic transportation, specific studies were realized on field effect transistor devices with carbon nanotubes as the conduction channel (Chapter 4). They evidence strong electronic communications between the inorganic complexes and the carbon nanotubes onto which they are assembled in the devices. Even if in the end no coupling was observed between the magnetic properties of the inorganic complexes and the transport ones of the carbon nanotubes, numerous unexpected and very interesting phenomena such as ambipolar behavior, charge transfer effect or bond cleavage were evidenced. As for the optoelectronic coupling which was investigated for photocatalytic applications, a first step was made as the transport of the carbon nanotube field effect transistor devices onto which a complex was assembled shows a strong dependence with the applied light irradiation.La spintronique molĂ©culaire et la photocatalyse sont deux domaines en constante Ă©volution. Le premier sâattache Ă exploiter la possibilitĂ© de coupler deux phĂ©nomĂšnes physiques, Ă savoir le transport dâun flux de porteurs de charges et le spin de lâĂ©lectron, tandis que le second se concentre sur lâexaltation des propriĂ©tĂ©s chimiques de transfert dâĂ©lectrons dâune espĂšce donnĂ©e grĂące au phĂ©nomĂšne physique dâirradiation lumineuse. Depuis quelques annĂ©es, les nanotubes de carbone ont suscitĂ© un grand intĂ©rĂȘt Ă la fois en tant que composant pour la spintronique molĂ©culaire, en raison de leur grande cohĂ©rence de spin, et en tant que support idĂ©al pour la catalyse molĂ©culaire, grĂące Ă leurs exceptionnelles propriĂ©tĂ©s Ă©lectroniques de surface. Au cours de ce travail de thĂšse, nous nous sommes attachĂ©s Ă concevoir des complexes inorganiques possĂ©dant des propriĂ©tĂ©s physiques, (magnĂ©tiques ou optiques) et des propriĂ©tĂ©s chimiques (permettant leur assemblage non-covalent sur des nanotubes de carbone monoparoi) de maniĂšre Ă former des adduits complexes inorganiques-nanotubes aux propriĂ©tĂ©s exploitables en spintronique molĂ©culaire et en photocatalyse. Les propriĂ©tĂ©s des complexes synthĂ©tisĂ©s ont Ă©tĂ© extensivement caractĂ©risĂ©es (Chapitre 2), et les plus prometteurs de ces composĂ©s ont Ă©tĂ© assemblĂ©s avec succĂšs sur les nanotubes de carbone (Chapitre 3), comme en attestent les mesures spectroscopiques rĂ©alisĂ©es. Enfin, les deux domaines dâapplications concernĂ©s par nos travaux faisant intervenir des phĂ©nomĂšnes de transport Ă©lectronique, des Ă©tudes spĂ©cifiques sur des dispositifs Ă©lectriques de type transistor Ă effet de champ dont le canal de conduction est constituĂ© de nanotubes de carbone ont Ă©tĂ© rĂ©alisĂ©es (Chapitre 4). Celles-ci mettent Ă chaque fois en Ă©vidence lâexistence dâune communication Ă©lectronique entre les complexes inorganique et les nanotubes de carbone sur lesquels ils sont assemblĂ©s au sein des dispositifs. Bien quâau final un couplage entre les propriĂ©tĂ©s magnĂ©tiques des complexes synthĂ©tisĂ©s et les propriĂ©tĂ©s de transport des nanotubes nâait pas pu ĂȘtre mis en Ă©vidence, de nombreux phĂ©nomĂšnes inattendus et extrĂȘmement intĂ©ressants tels que des effets ambipolaires, des transferts de charge ou des ruptures de liaisons ont Ă©tĂ© observĂ©s. Par contre, un fort couplage opto-Ă©lectronique a pu ĂȘtre obtenu entre un complexe et le flux de porteurs de charge des dispositifs, ce qui sâavĂšre ĂȘtre de trĂšs bon augure pour des futures applications en photocatalyse
La ville est un dessin.
Par Ă©tapes successives, la ville se transforme. Par un entremĂȘlement dâhistoire et gĂ©ographie, certaines villes font Ă©voluer leurs espaces Ă un tel point que lâon ne peut souvent ni reconnaĂźtre, ni comprendre un espace que lâon traverse et quâon a pourtant bien connu il nây a pas si longtemps. Le lien qui nous liait avec le territoire est soit rompu, soit inexistant. Ă lâheure oĂč les villes se transforment en mĂ©tropoles ou en mĂ©gapoles, mon objectif est de contribuer Ă ..
Assemblage de complexes inorganiques sur nanotubes de carbone monoparoi : Applications à la spintronique moléculaire et à la photocatalyse
Molecular spintronic and photocatalysis are two fields in constant evolution. While the first deals with the coupling of two physical properties, the flux of charge carriers and the spin of the electron, the second is focusing on the enhancement of the electron transfer of chemical species under light irradiation. Recently, there has been an increasing interest in carbon nanotubes as new components for molecular spintronics, since they possess high spin coherence, and as ideal materials for molecular catalysis, for their tremendous electronic surface properties. Our work consisted in conceiving inorganic complexes with both physical (magnetic or optic) and chemical (ability of realizing non covalent assembly on single-walled carbon nanotubes) properties, in order to create new nanotube-complex nanohybrids which could be exploited for molecular spintronics or photocatalysis applications. The properties of the synthesized complexes were extensively characterized (Chapter 2), and the most promising molecules were successfully assembled onto carbon nanotubes, as is proven by the spectroscopic measurement which were performed (Chapter 3). Finally, since both domains of applications we considered involve electronic transportation, specific studies were realized on field effect transistor devices with carbon nanotubes as the conduction channel (Chapter 4). They evidence strong electronic communications between the inorganic complexes and the carbon nanotubes onto which they are assembled in the devices. Even if in the end no coupling was observed between the magnetic properties of the inorganic complexes and the transport ones of the carbon nanotubes, numerous unexpected and very interesting phenomena such as ambipolar behavior, charge transfer effect or bond cleavage were evidenced. As for the optoelectronic coupling which was investigated for photocatalytic applications, a first step was made as the transport of the carbon nanotube field effect transistor devices onto which a complex was assembled shows a strong dependence with the applied light irradiation.La spintronique molĂ©culaire et la photocatalyse sont deux domaines en constante Ă©volution. Le premier sâattache Ă exploiter la possibilitĂ© de coupler deux phĂ©nomĂšnes physiques, Ă savoir le transport dâun flux de porteurs de charges et le spin de lâĂ©lectron, tandis que le second se concentre sur lâexaltation des propriĂ©tĂ©s chimiques de transfert dâĂ©lectrons dâune espĂšce donnĂ©e grĂące au phĂ©nomĂšne physique dâirradiation lumineuse. Depuis quelques annĂ©es, les nanotubes de carbone ont suscitĂ© un grand intĂ©rĂȘt Ă la fois en tant que composant pour la spintronique molĂ©culaire, en raison de leur grande cohĂ©rence de spin, et en tant que support idĂ©al pour la catalyse molĂ©culaire, grĂące Ă leurs exceptionnelles propriĂ©tĂ©s Ă©lectroniques de surface. Au cours de ce travail de thĂšse, nous nous sommes attachĂ©s Ă concevoir des complexes inorganiques possĂ©dant des propriĂ©tĂ©s physiques, (magnĂ©tiques ou optiques) et des propriĂ©tĂ©s chimiques (permettant leur assemblage non-covalent sur des nanotubes de carbone monoparoi) de maniĂšre Ă former des adduits complexes inorganiques-nanotubes aux propriĂ©tĂ©s exploitables en spintronique molĂ©culaire et en photocatalyse. Les propriĂ©tĂ©s des complexes synthĂ©tisĂ©s ont Ă©tĂ© extensivement caractĂ©risĂ©es (Chapitre 2), et les plus prometteurs de ces composĂ©s ont Ă©tĂ© assemblĂ©s avec succĂšs sur les nanotubes de carbone (Chapitre 3), comme en attestent les mesures spectroscopiques rĂ©alisĂ©es. Enfin, les deux domaines dâapplications concernĂ©s par nos travaux faisant intervenir des phĂ©nomĂšnes de transport Ă©lectronique, des Ă©tudes spĂ©cifiques sur des dispositifs Ă©lectriques de type transistor Ă effet de champ dont le canal de conduction est constituĂ© de nanotubes de carbone ont Ă©tĂ© rĂ©alisĂ©es (Chapitre 4). Celles-ci mettent Ă chaque fois en Ă©vidence lâexistence dâune communication Ă©lectronique entre les complexes inorganique et les nanotubes de carbone sur lesquels ils sont assemblĂ©s au sein des dispositifs. Bien quâau final un couplage entre les propriĂ©tĂ©s magnĂ©tiques des complexes synthĂ©tisĂ©s et les propriĂ©tĂ©s de transport des nanotubes nâait pas pu ĂȘtre mis en Ă©vidence, de nombreux phĂ©nomĂšnes inattendus et extrĂȘmement intĂ©ressants tels que des effets ambipolaires, des transferts de charge ou des ruptures de liaisons ont Ă©tĂ© observĂ©s. Par contre, un fort couplage opto-Ă©lectronique a pu ĂȘtre obtenu entre un complexe et le flux de porteurs de charge des dispositifs, ce qui sâavĂšre ĂȘtre de trĂšs bon augure pour des futures applications en photocatalyse
Inorganic complexes assembly onto single-walled carbon nanotubes for molecular spintronic and photocatalytic
La spintronique molĂ©culaire et la photocatalyse sont deux domaines en constante Ă©volution. Le premier sâattache Ă exploiter la possibilitĂ© de coupler deux phĂ©nomĂšnes physiques, Ă savoir le transport dâun flux de porteurs de charges et le spin de lâĂ©lectron, tandis que le second se concentre sur lâexaltation des propriĂ©tĂ©s chimiques de transfert dâĂ©lectrons dâune espĂšce donnĂ©e grĂące au phĂ©nomĂšne physique dâirradiation lumineuse. Depuis quelques annĂ©es, les nanotubes de carbone ont suscitĂ© un grand intĂ©rĂȘt Ă la fois en tant que composant pour la spintronique molĂ©culaire, en raison de leur grande cohĂ©rence de spin, et en tant que support idĂ©al pour la catalyse molĂ©culaire, grĂące Ă leurs exceptionnelles propriĂ©tĂ©s Ă©lectroniques de surface. Au cours de ce travail de thĂšse, nous nous sommes attachĂ©s Ă concevoir des complexes inorganiques possĂ©dant des propriĂ©tĂ©s physiques, (magnĂ©tiques ou optiques) et des propriĂ©tĂ©s chimiques (permettant leur assemblage non-covalent sur des nanotubes de carbone monoparoi) de maniĂšre Ă former des adduits complexes inorganiques-nanotubes aux propriĂ©tĂ©s exploitables en spintronique molĂ©culaire et en photocatalyse. Les propriĂ©tĂ©s des complexes synthĂ©tisĂ©s ont Ă©tĂ© extensivement caractĂ©risĂ©es (Chapitre 2), et les plus prometteurs de ces composĂ©s ont Ă©tĂ© assemblĂ©s avec succĂšs sur les nanotubes de carbone (Chapitre 3), comme en attestent les mesures spectroscopiques rĂ©alisĂ©es. Enfin, les deux domaines dâapplications concernĂ©s par nos travaux faisant intervenir des phĂ©nomĂšnes de transport Ă©lectronique, des Ă©tudes spĂ©cifiques sur des dispositifs Ă©lectriques de type transistor Ă effet de champ dont le canal de conduction est constituĂ© de nanotubes de carbone ont Ă©tĂ© rĂ©alisĂ©es (Chapitre 4). Celles-ci mettent Ă chaque fois en Ă©vidence lâexistence dâune communication Ă©lectronique entre les complexes inorganique et les nanotubes de carbone sur lesquels ils sont assemblĂ©s au sein des dispositifs. Bien quâau final un couplage entre les propriĂ©tĂ©s magnĂ©tiques des complexes synthĂ©tisĂ©s et les propriĂ©tĂ©s de transport des nanotubes nâait pas pu ĂȘtre mis en Ă©vidence, de nombreux phĂ©nomĂšnes inattendus et extrĂȘmement intĂ©ressants tels que des effets ambipolaires, des transferts de charge ou des ruptures de liaisons ont Ă©tĂ© observĂ©s. Par contre, un fort couplage opto-Ă©lectronique a pu ĂȘtre obtenu entre un complexe et le flux de porteurs de charge des dispositifs, ce qui sâavĂšre ĂȘtre de trĂšs bon augure pour des futures applications en photocatalyse.Molecular spintronic and photocatalysis are two fields in constant evolution. While the first deals with the coupling of two physical properties, the flux of charge carriers and the spin of the electron, the second is focusing on the enhancement of the electron transfer of chemical species under light irradiation. Recently, there has been an increasing interest in carbon nanotubes as new components for molecular spintronics, since they possess high spin coherence, and as ideal materials for molecular catalysis, for their tremendous electronic surface properties. Our work consisted in conceiving inorganic complexes with both physical (magnetic or optic) and chemical (ability of realizing non covalent assembly on single-walled carbon nanotubes) properties, in order to create new nanotube-complex nanohybrids which could be exploited for molecular spintronics or photocatalysis applications. The properties of the synthesized complexes were extensively characterized (Chapter 2), and the most promising molecules were successfully assembled onto carbon nanotubes, as is proven by the spectroscopic measurement which were performed (Chapter 3). Finally, since both domains of applications we considered involve electronic transportation, specific studies were realized on field effect transistor devices with carbon nanotubes as the conduction channel (Chapter 4). They evidence strong electronic communications between the inorganic complexes and the carbon nanotubes onto which they are assembled in the devices. Even if in the end no coupling was observed between the magnetic properties of the inorganic complexes and the transport ones of the carbon nanotubes, numerous unexpected and very interesting phenomena such as ambipolar behavior, charge transfer effect or bond cleavage were evidenced. As for the optoelectronic coupling which was investigated for photocatalytic applications, a first step was made as the transport of the carbon nanotube field effect transistor devices onto which a complex was assembled shows a strong dependence with the applied light irradiation
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