Semiconductor nanocrystals are interesting candidates as new light-absorbing materials for photovoltaic (PV) devices. They can be dispersed in solvents and cheaply deposited at low-temperature on various substrates. Also, the nanocrystals have unique optical properties depending on their size due to the quantum size effect and moreover it is easy to uniformly control their stoichiometry. CdTe/CdSe/CdTe heterostructure nanorods and I-III-VI₂ nanocrystals were selected to synthesize and investigate in order to utilize the benefits of colloidal nanocrystals described above. Colloidal nanorods with linear CdTe/CdSe/CdTe heterojunctions were synthesized by sequential reactant injection. After CdTe deposition at the ends of initially formed CdSe nanorods, continued heating in solution leads to Se-Te interdiffusion across the heterojunctions and coalescence to decreased aspect ratio. The Se-Te interdiffusion rates were measured by mapping the composition profile using nanobeam energy dispersive X-ray spectroscopy (EDS). The rate of nanorod coalescence was also measured and compared to model predictions using a continuum viscous flow model. The synthetic method of monodisperse chalcopyrite (tetragonal) CuInSe₂ nanocrystals was also developed. The nanocrystals have trigonal pyramidal shape with one polar and three non-polar surface facets. When drop-cast onto carbon substrates, the nanocrystals self-assemble into close-packed monolayers with triangular (honeycomb) lattice structure. Moreover, the effect of excess Cu precursor (CuCl) was studied for the formation of monodisperse trigonal pyramidal CuInSe₂ nanocrystals. The formation mechanism of monodisperse trigonal pyramidal CuInSe₂ nanocrystals was suggested with regard to excess amount of CuCl precursor, based on the nucleationgrowth model of colloidal nanocrystal formation. A new wurtzite phase of CuInS₂, CuInSe₂, and Cu(InxGa1-x)Se₂ (CIGS) was observed in nanocrystals synthesized by heating metal precursors and Se-(or S-)urea in alkylamine. X-ray diffraction (XRD) showed the predominant phase to be wurtzite (hexagonal) instead of chalcopyrite (tetragonal). High resolution transmission electron microscopy (TEM), however, revealed polytypism in the nanocrystals, with the wurtzite phase interfaced with significant chalcopyrite domains. / text

Silicon nanowires, silicon nanorods, and magnetic nanocrystals have shown interesting size, shape, mechanical, electronic, and/or magnetic properties and many have proposed their use in exciting applications. However, before these materials can be applied, it is critical to fully understand their properties and how to synthesize them economically and reproducibly. Silicon nanowires were synthesized in high boiling point ambient pressure solvents using gold and bismuth nanocrystals seeds and trisilane as the silicon precursor. Reactions temperatures as low as 410°C were used to promote the solution-liquid-solid (SLS) growth of silicon nanowires. The silicon nanowires synthesis was optimized to produce 5 mg of silicon nanowires with average diameters of 30 nm and lengths exceeding 2 [mu]m by adjusting the silicon to gold ratio in the injection mixture and reaction temperature. Silicon nanorods were synthesized using a solution-based arrested-SLS growth approach where gold seeds, trisilane, and a dodecylamine were vital to the success. Dodecylamine was found to prevent gold seed coalescence at high temperatures -- creating small diameter rods -- and bond to the crystalline silicon surface -- preventing silicon nanorod aggregation. Furthermore, an etching strategy was developed using an emulsion of aqua regia and chloroform to remove the gold seeds from the silicon nanorods tip. A thin silicon shell surrounding the gold seed of the silicon nanorod was subsequently observed. Multifunctional colloidal core-shell nanoparticles of iron platinum or iron oxide encapsulated in fluorescent dye doped silica shells were also synthesized. The as-prepared magnetic nanocrystals are initially hydrophobic and were coated with a uniform silica shell using a microemulsion approach. These colloidal heterostructures have the potential to be used as dual-purpose tags, exhibiting a fluorescent signal that could be combined with enhanced magnetic resonance imaging contrast. Compositionally-ordered, single domain, antiferromagnetic L1₂ FePt₃ and ferromagnetic L1₀ FePt nanocrystals were synthesized by coating colloidally-grown Pt-rich or stoichiometricly equal Fe-Pt nanocrystals with thermally-stable SiO₂ and annealing at high temperature. Without the silica coating, the nanocrystals transform predominately into the L1₀ FePt phase due to interparticle diffusion of Fe and Pt atoms. Magnetization measurements of the L1₂ FePt₃ nanocrystals revealed two antiferromagnetic transitions near the bulk Neél temperatures of 100K and 160K. Combining L1₂ FePt₃ nanocrystals with L1₀ FePt nanocrystals was found to produce a constriction in field-dependent magnetization loops that has previously been observed near zero applied field in ensemble measurements of single domain silica-coated L1₀ FePt nanocrystals. Dipole interactions between FePt@SiO₂ nanoparticles with varying SiO₂ shell thickness was also explored. / text

Grâce au récent développement des synthèses chimiques en suspension colloïdale, de nouveaux photosensibilisateurs possédant une grande surface spécifique ont été envisagés dans cette thèse pour supporter des réactions d'oxydoréduction induite par la lumière. Ce travail s'inscrit donc dans la recherche de nouvelles sources d'énergie pour répondre aux problèmes inhérents à l'appauvrissement des énergies fossiles. Ainsi des nanobâtonnets quantiques de composition cœur@coquille et des nanobâtonnets d'or ont été synthétisés. Leur anisotropie de forme permet également de les assembler dans des phases cristal liquides. Grâce à une méthode de séchage originale, des assemblages hiérarchiques ont été obtenus, ce qui est prometteur pour réaliser des réactions de photocatalyses sur ces assemblages par la suite. Par ailleurs, un catalyseur naturel, une hydrogénase, a été greffée avec succès sur les nanocristaux et étudié en électrochimie. Ces systèmes permettraient d'améliorer les performances des biopiles à combustibles. / With the recent development of chemical synthesis in colloidal suspension, new photosensitizers with high surface area have been considered in this thesis to support redox reactions induced by light. This work is therefore in the scope of finding new energy sources to meet the problems posed by the depletion of fossil fuels. Quantum nanorods with a core@shell composition and gold nanorods were synthesized. Their shape anisotropy permits to assemble them in liquid crystal phases. Thanks to an original method of drying, hierarchical assemblies were obtained, which is promising to perform photoredox reactions on these assemblies thereafter. Furthermore, a natural catalyst, a hydrogenase was successfully grafted onto the nanocrystals and studied in electrochemistry. These systems would improve the performance of biofuel cells.

Im Bereich opto-elektronischer Sensortechnik ist ein eindeutiger Trend hin zu immer kleineren Bauelementen und immer spezifischeren Messanwendungen zu erkennen. Plasmonische Materialien auf der Basis von Nanostrukturen bieten sich hierbei hervorragend für dieses Aufgabenfeld an. Deren optische Absorbanzpeaks lassen sich über die geometrischen Parameter der Nanostrukturen einfach und präzise steuern und reagieren äußerst empfindlich auf Brechungsindexänderungen im Umgebungsmedium. Die Herstellung von aufrecht stehenden, teppichartig angeordneten Nanorods auf Basis von anodisierten Aluminiumoxidmatrizen bietet als skalierbares Bottom-up-Verfahren eine einzigartige Kombination aus Prozessgeschwindigkeit, Steuerbarkeit und Kosteneffizienz. In der vorliegenden Dissertation wurde untersucht, wie sich verschiedene Sputterparameter während der Herstellung von Aluminiumdünnschichten auf deren Anodisierungseigenschaften, sowie die anschließende Porenbefüllung und die plasmonischen Eigenschaften des so erzeugten Materials auswirken. Hierzu wurde reines Aluminium bei verschiedenen Sputterleistungen und -raten abgeschieden und hinsichtlich seiner Oberflächenkonfiguration und Prozessierbarkeit im bereits etablierten Nanorodproduktionsverfahren untersucht. Gleichwohl fanden Versuche statt, Aluminiumschichten mit einer schwachen Siliziumlegierung sowie durch reaktives Sputtern mit Sauerstoff voroxidiertes Aluminium zu anodisieren und für die Nanorodherstellung zu nutzen. Als typisches Ergebnis dieser Versuche zeigt sich eine deutliche Verbesserung des Anodisierungs- und Abscheideverhaltens, wenn die Sputterparameter so gewählt werden, dass eine möglichst feinkristalline Schicht abgeschieden wird. Während die Variation der Sputterleistung nur in einer mäßigen Verbesserung und die Siliziumlegierung sogar in einer Verschlechterung der optischen Eigenschaften resultieren, zeigt sich die Sauerstoffzugabe als äußerst vorteilhaft für den Herstellungsprozess sowie die plasmonischen Eigenschaften der fertigen Strukturen. Hierbei weisen Aluminiumschichten mit einem Sauerstoffanteil von 10 22 at.% die gleichmäßigste Anodisierung sowie die schmalsten Plasmonenresonanzpeaks auf, bei gleichzeitig hoher Reproduzierbarkeit. Für derartige Proben konnte eine annähernd vollständige Porenbefüllung erreicht werden. Weiterhin ist die Breite der Plasmonenresonanz hier vergleichbar mit der eines simulierten, defektfreien Nanorodarrays mit perfekt hexagonaler Nanorodanordnung, sodass von einer deutlichen Optimierung gesprochen werden kann, welche nun weitere Untersuchungen an diesem System oder sogar eine großtechnische Produktion ermöglicht Letztendlich offenbart eine quantitative Analyse der Strom-Zeit-Kurve der Anodisierung, dass diese in Form und Ausprägung mit der Güte der plasmonischen Eigenschaften der so produzierten Strukturen korreliert. Somit bietet sich diese als schnelles und günstiges Verfahren zur Qualitätskontrolle in einem sehr frühen Prozessstadium an. / Optical sensing witnesses an increasing trend towards smaller components and more specific applications. Nanostructure-based materials excellently fulfil these kinds of task. Their optical absorbance peaks are easily and precisely controllable by changing the structures‘ geometrical parameters, and have shown to be highly sensitive to refractive index changes of the surrounding medium. The fabrication of free-standing arrays of metallic nanorods based on anodised aluminium oxide matrices as a scalable bottom-up process offers a unique combination of throughput in production, process control and cost efficiency. The scope of the present dissertation thesis is the exploration of different sputtering parameters and techniques for the fabrication of aluminium thin-films, their influence on the anodisation properties as well as subsequent pore filling, and of course the optical properties of the final plasmonic structure. For this, pure aluminium was deposited at different sputtering powers and rates, and was investigated regarding its surface configuration as well as its usability within the well-established nanorod fabrication process. Similarly, attempts were made to anodise aluminium alloyed with small quantities of silicon as well as substoichiometric aluminium oxide, which was prepared by reactive sputtering under partial oxygen pressure. As a typical result of these studies, it was found that a considerable improvement of anodisation and electroplating behaviour could be achieved, provided the sputtering conditions were chosen such that the deposited films\' crystal size becomes as small as possible. While the variation of the sputtering power lead only to a marginal improvement and the silicon admixture even deteriorated the sample quality, the use of partially oxidised aluminium layers proved to be highly advantageous for the fabrication process as well as the plasmonic properties of the final structures. The optimal oxygen content was found to be 10 22 at.%, with these samples showing the most regular anodisation behaviour, the smallest absorbance peak width, and at the same time a high reproducibility. Furthermore, the peak width of these samples is comparable to that of simulated, defect-free nanorod arrays in a perfect hexagonal arrangement. These fabrication parameters can therefore be viewed as highly optimised and well-suited for further investigations of this material or even a large-scale production process. Finally, a quantitative analysis of the current-time-curve of an anodisation process reveals a correlation between its characteristics and the samples’ plasmonic qualities. Hence, the analysis of this curve may be used as a fast and cheap method of quality control at the early stages of the fabrication process.

No / Spheric and anisotropic gold nanoparticles (GNPs) such as rods, stars or nanoprism prepared using hexadecyltrimethyl ammonium bromide (CTAB) as the stabilising agent have received a great deal of interest in the last years. The literature procedures exploited lead to GNPs in aqueous solution. We herein describe a fast, efficient, and cheap method to transfer particles of different shapes from water into toluene solution via ligand exchange (CTAB to dodecanethiol), which was mediated by acetone as a cosolvent. Absorption spectra and TEM-pictures before and after the transfer revealed that the particles survived the transfer intact and without change in shape.

Im Bereich opto-elektronischer Sensortechnik ist ein eindeutiger Trend hin zu immer kleineren Bauelementen und immer spezifischeren Messanwendungen zu erkennen. Plasmonische Materialien auf der Basis von Nanostrukturen bieten sich hierbei hervorragend für dieses Aufgabenfeld an. Deren optische Absorbanzpeaks lassen sich über die geometrischen Parameter der Nanostrukturen einfach und präzise steuern und reagieren äußerst empfindlich auf Brechungsindexänderungen im Umgebungsmedium. Die Herstellung von aufrecht stehenden, teppichartig angeordneten Nanorods auf Basis von anodisierten Aluminiumoxidmatrizen bietet als skalierbares Bottom-up-Verfahren eine einzigartige Kombination aus Prozessgeschwindigkeit, Steuerbarkeit und Kosteneffizienz. In der vorliegenden Dissertation wurde untersucht, wie sich verschiedene Sputterparameter während der Herstellung von Aluminiumdünnschichten auf deren Anodisierungseigenschaften, sowie die anschließende Porenbefüllung und die plasmonischen Eigenschaften des so erzeugten Materials auswirken. Hierzu wurde reines Aluminium bei verschiedenen Sputterleistungen und -raten abgeschieden und hinsichtlich seiner Oberflächenkonfiguration und Prozessierbarkeit im bereits etablierten Nanorodproduktionsverfahren untersucht. Gleichwohl fanden Versuche statt, Aluminiumschichten mit einer schwachen Siliziumlegierung sowie durch reaktives Sputtern mit Sauerstoff voroxidiertes Aluminium zu anodisieren und für die Nanorodherstellung zu nutzen. Als typisches Ergebnis dieser Versuche zeigt sich eine deutliche Verbesserung des Anodisierungs- und Abscheideverhaltens, wenn die Sputterparameter so gewählt werden, dass eine möglichst feinkristalline Schicht abgeschieden wird. Während die Variation der Sputterleistung nur in einer mäßigen Verbesserung und die Siliziumlegierung sogar in einer Verschlechterung der optischen Eigenschaften resultieren, zeigt sich die Sauerstoffzugabe als äußerst vorteilhaft für den Herstellungsprozess sowie die plasmonischen Eigenschaften der fertigen Strukturen. Hierbei weisen Aluminiumschichten mit einem Sauerstoffanteil von 10 22 at.% die gleichmäßigste Anodisierung sowie die schmalsten Plasmonenresonanzpeaks auf, bei gleichzeitig hoher Reproduzierbarkeit. Für derartige Proben konnte eine annähernd vollständige Porenbefüllung erreicht werden. Weiterhin ist die Breite der Plasmonenresonanz hier vergleichbar mit der eines simulierten, defektfreien Nanorodarrays mit perfekt hexagonaler Nanorodanordnung, sodass von einer deutlichen Optimierung gesprochen werden kann, welche nun weitere Untersuchungen an diesem System oder sogar eine großtechnische Produktion ermöglicht Letztendlich offenbart eine quantitative Analyse der Strom-Zeit-Kurve der Anodisierung, dass diese in Form und Ausprägung mit der Güte der plasmonischen Eigenschaften der so produzierten Strukturen korreliert. Somit bietet sich diese als schnelles und günstiges Verfahren zur Qualitätskontrolle in einem sehr frühen Prozessstadium an. / Optical sensing witnesses an increasing trend towards smaller components and more specific applications. Nanostructure-based materials excellently fulfil these kinds of task. Their optical absorbance peaks are easily and precisely controllable by changing the structures‘ geometrical parameters, and have shown to be highly sensitive to refractive index changes of the surrounding medium. The fabrication of free-standing arrays of metallic nanorods based on anodised aluminium oxide matrices as a scalable bottom-up process offers a unique combination of throughput in production, process control and cost efficiency. The scope of the present dissertation thesis is the exploration of different sputtering parameters and techniques for the fabrication of aluminium thin-films, their influence on the anodisation properties as well as subsequent pore filling, and of course the optical properties of the final plasmonic structure. For this, pure aluminium was deposited at different sputtering powers and rates, and was investigated regarding its surface configuration as well as its usability within the well-established nanorod fabrication process. Similarly, attempts were made to anodise aluminium alloyed with small quantities of silicon as well as substoichiometric aluminium oxide, which was prepared by reactive sputtering under partial oxygen pressure. As a typical result of these studies, it was found that a considerable improvement of anodisation and electroplating behaviour could be achieved, provided the sputtering conditions were chosen such that the deposited films\' crystal size becomes as small as possible. While the variation of the sputtering power lead only to a marginal improvement and the silicon admixture even deteriorated the sample quality, the use of partially oxidised aluminium layers proved to be highly advantageous for the fabrication process as well as the plasmonic properties of the final structures. The optimal oxygen content was found to be 10 22 at.%, with these samples showing the most regular anodisation behaviour, the smallest absorbance peak width, and at the same time a high reproducibility. Furthermore, the peak width of these samples is comparable to that of simulated, defect-free nanorod arrays in a perfect hexagonal arrangement. These fabrication parameters can therefore be viewed as highly optimised and well-suited for further investigations of this material or even a large-scale production process. Finally, a quantitative analysis of the current-time-curve of an anodisation process reveals a correlation between its characteristics and the samples’ plasmonic qualities. Hence, the analysis of this curve may be used as a fast and cheap method of quality control at the early stages of the fabrication process.

Doctor of Philosophy / Department of Chemistry / Kenneth J. Klabunde / First, a new tiara Pd(II) thiolate complex-[Pd(SC[subscript]12H[subscript]25)[subscript]2][subscript]6 has been synthesized and fully characterized. Then the complex was further used as a single-source precursor to prepare nearly monodisperse palladium sulfide (PdS) nanoparticles through the high-temperature-induced decomposition in diphenyl ether. Secondly, the influence of dodecanethiol on the product distribution upon heating a Pd(II)-octylamine system was investigated. The molar ratio of octylamine to Pd(II) was fixed at 20:1, and the concentration of dodecanethiol was changed systematically. Without thiol ligand, only aggregated Pd(0) particles were obtained due to the reduction of Pd(II) by octylamine. When the molar ratio of dodecanethiol to Pd(II) was increased to 0.5, highly monodisperse sulfurized palladium nanoparticles with diameter 7.55 [plus or minus] 0.73 nm were generated. When the molar ratio reached to 2, only a thiolate complex-[Pd(SC[subscript]12H[subscript]25)[subscript]2][subscript]6 was found as the final product. Thirdly, we report a facile method to prepare nearly monodisperse Pd nanoparticles by heating Pd(II) ions in 4-tert-butyltoluene solvent, in the presence of oleylamine and trioctylphosphine (TOP) ligands. It has been found the concentration of TOP ligand was highly pivotal for the formation of Pd nanoparticles. Without TOP, only aggregated Pd particles were obtained due to the reduction of Pd(II) by oleylamine. When the molar ratio of TOP to Pd(II) was less than two, well-protected Pd nanoparticles were obtained. However, when the molar ratio reached to two, only Pd(II)-TOP coordination complexes were obtained as the final product. Fourthly, we present a novel way to synthesize cadmium selenide (CdSe) nanoparticles from a heterogeneous system only containing cadmium oxide, trioctylphosphine, and trioctylphosphine selenide. Last, the formation of magnesium oxychloride (Mg[subscript]x(OH)[subscript]yCl[subscript]z•nH[subscript]2O) nanorods from the system MgO-MgCl[subscript]2-H[subscript]2O was investigated. By changing the amounts of the starting materials, short nanorods (< 1 micron) or long nanorods (up to 20 micron) could be obtained readily with the aspect ratio in the range of 10-70. The resulting magnesium oxychloride nanorods could be further transformed to magnesium hydroxide (Mg(OH)[subscript]2) nanorods by treating with NaOH.

Nanomaterials such as carbon nanotubes, gold nanorods, magnetic nanocrystals, and binary nanocrystal superlattices have exciting potential applications. However, before these ideas can be applied, it is imperative to fully understand the materials synthesis. Multiwall carbon nanotubes were synthesized in supercritical toluene using cobaltocene, nickelocene, ferrocene, or metal nanocrystals as catalysts. Toluene served as both the solvent and carbon source for nanotube growth. The reaction was optimized by introducing supplemental carbon sources; either hexane or ethanol increased the yield relative to pure toluene and catalytic amounts of water minimized carbon filament and amorphous carbon formation. Gold nanorods were synthesized by the colloidal seed-mediated, surfactantassisted approach using cetyltrimethylammonium bromide (CTAB) obtained from ten different suppliers. The gold nanorod yield depended strongly on the CTAB used: with the same recipe, three of the CTABs produced only spherical particles, whereas the other CTABs produced nanorods with nearly 100% yield. Inductively coupled plasma mass spectrometry revealed a trace iodide impurity in the CTABs that did not yield nanorods. Further experiments introducing potassium iodide to the nanorod synthesis verified the detrimental effect of iodide on nanorod formation. Multifunctional colloidal core-shell nanoparticles of magnetic nanocrystals or gold nanorods coated with a fluorescent dye (Tris(2,2 -bipyridyl)dichlororuthenium(II) hexahydrate) doped silica shells were also synthesized. The as-prepared magnetic nanocrystals were initially hydrophobic and silica coated using a microemulsion approach, while the gold nanorods were hydrophilic and silica coated using a Stöber process. These colloidal heterostructures have the potential to be used as dual-purpose tags, exhibiting a fluorescent signal that could be combined with either dark-field optical contrast or enhanced contrast in magnetic resonance imaging. Binary superlattices (BSLs) of large iron oxide and small gold nanocrystals were assembled by slow evaporation of colloidal dispersions on tilted substrates. SEM and grazing incidence small angle X-ray scattering (GISAXS) confirmed the BSLs were simple hexagonal AB2 superlattices with long range order. GISAXS also revealed that the superlattice was slightly contracted perpendicular to the substrate as a result of solvent drying during the deposition process. Additionally, in some BSLs nearly periodic superlattice dislocations consisting of inserted half-planes of gold nanocrystals were observed. / text

The time-dependent wettability of nickel nanorod arrays was studied by measuring their water contact angles as a function of "aging" time in air. The nickel nanorod arrays were deposited on silicon substrates by DC magnetron sputtering using an oblique angle of 85° with respect to the substrate normal. By changing the deposition time from 10 to 90 min., the diameter, height, and separation of the nanorods were varied. The water contact angles of each sample were then periodically measured from a minimum aging time of 30 min. after deposition and exposure to air, up to a maximum aging time of three months. The initial water contact angles for all samples were approximately equal to 8o, indicating that the nickel nanorod arrays were initially superhydrophilic. As the samples aged in air, however, they all showed increasing contact angles as a function of time that were nonlinear with different rates. The results can be grouped into two categories: thinner samples with shorter deposition times (10 to 55 min) demonstrated faster rates of increase in contact angle, and thicker samples with longer deposition times (60 and 90 min.) showed slower rates. The increase in contact angle with time indicates that the Ni nanorods become more hydrophobic with aging time in air. Surface chemical analysis demonstrates that this increase in hydrophobicity may be due to oxidization and hydrocarbon contamination, which depend on the nanorod morphology. X-ray photoelectron spectroscopy results indicate that thinner samples (10-55 min. deposition time) have more adsorbed carbon as compared to thicker samples (60 and 90 min.). It appears that the reactivity of the Ni nanorods with air ambient is enhanced for shorter, smaller-diameter nanorods.

Cette thèse comporte trois parties principales : la première concerne la synthèse et la fonctionnalisation des nanoparticules (NPs) d’or de forme sphérique et cylindrique. Les NPs d’or sont obtenues par réduction d’un sel métallique. En faisant varier certains paramètres de synthèse tels que la concentration en sels et/ou la concentration en réducteur, on peut facilement ajuster la taille de NPs sphériques. Bien qu’il existe diverses méthodes permettant de préparer des NPs cylindriques, il subsiste un problème de reproductibilité basée sur la pureté des produits de synthèse. Les différentes analyses de CTAB nous ont permis de proposer des solutions à ce problème. La fonctionnalisation de la surface des NPs d’or permet d’apporter à ces dernières de nouvelles propriétés tout en conservant leurs propriétés intrinsèques. Le but de cette fonctionnalisation est de modifier la surface des NPs en fonction des applications visées. Nous présentons ainsi différentes études de fonctionnalisation par des polyélectrolytes (PEI et PSS), des couches oxydes de SiO2, et de TiO2 et par le TDBC. La réponse optique des NPs d’or étant sensible à l’indice de réfraction du milieu environnant, il est possible de suivre et de quantifier cette fonctionnalisation par spectroscopie d’absorption. Dans une seconde partie, nous avons développé une voie de synthèse simple permettant de préparer le cœur coquille Au@TDBC sans ajout supplémentaire de sels ou de bases et à température ambiante. Etant donné qu’il est possible de moduler la taille des particules, l’optimisation du couplage fort entre les transitions électroniques du TDBC et les modes plasmon de résonances des Nps d’Au a été obtenu correspondant à une énergie de Rabi de 220 meV valeur qui n’a pas encore été obtenue avec un tel système. Dans une troisième partie, nous avons développé une nouvelle approche basée sur la méthode de Stöber pour fonctionnaliser les NPs avec des couches d’oxyde de SiO2 et de TiO2. L’utilisation des systèmes Au@TiO2 est une perspective intéressante en photocatalyse car le contact entre le métal et le semi-conducteur devrait entrainer une nette augmentation de l’efficacité photocatalytique. En effet, le métal agit comme un réservoir de photoélectrons améliorant le transfert de charges interfaciales tout en retardant la recombinaison des paires électrons-trous photo excités du semi-conducteur. / This thesis has three main parts: the first part relates to the synthesis and the functionalization of spherical gold nanoparticles (NPs) and nanorods. Gold NPs are obtained by chemical reduction of gold salt. By varying some synthesis parameters such as gold salt concentration and or reducing agent concentration, we can easily adjust the size of gold NPs. Different methods can be used to prepare gold nanorods, but there is a problem of reproducibility. This problem is based on the purity of products used to prepare gold nanorods. Different analysis of CTAB allowed us to propose solutions to this problem. Functionalization brings to gold NPs new properties. The aim of the functionalization is to modify the surface of gold NPs based on the intended applications. We present various functionalization of Au NPs by polyelectrolytes (PEI and PSS), oxides (SiO2 and TiO2) and TDBC. The optical response of Au NPs is sensitive to the refractive indexe of the surrounding medium, it is then possible to monitor and quantify this functionalization by absorption spectroscopy. In the second part of this work, we have developed a simple synthetic route for preparing Au@TDBC core shell without additional salts or bases at room temperature. Since it is possible to vary the particle size, optimization of the strong coupling between the electronic transitions of TDBC and the resonance plasmon of Au Nps obtained correspond to Rabi energy of 220 meV value which has not yet been achieved with such a system. In the third part, we have developed a new approach based on the Stöber method to functionalize the NPs with an oxide layer of SiO2 and TiO2. The use of Au@TiO2 core shell system is an interesting perspective in photocatalysis because the contact between metal and semiconductor should cause a marked increase in the photocatalytic efficiency. Indeed, the metal acts as a reservoir of photoelectrons improving the interfacial charge transfer while retarding the recombination of electron-hole pair of the semiconductor.