Dissertations / Theses on the topic 'Nanoparticle injection'

L'utilisation des nanobiotechnologies dans le domaine de la santé est en plein essor. Les nanoparticules de poly(acide lactique) (PLA) représentent un nanosystème biocompatible capable d'accroître la spécificité et l'efficacité de traitements thérapeutiques et vaccinaux administrables par voie muqueuse et intraveineuse. Toutefois, l'optimisation de ces nanosystèmes se heurte à une caractérisation incomplète de leur biodistribution in vivo, en particulier à l'échelle cellulaire.L'objectif de ce travail de thèse est d'enrichir les connaissances sur la biodistribution des nanoparticules de PLA in vivo après administration muqueuse ou intraveineuse, dans le but d'élargir les perspectives d'optimisation et d'utilisation. Animal complexe et adapté pour les études sur organisme-entier, le modèle du poisson-zèbre (Danio rerio) a été utilisé. Pour mener à bien ce projet, une méthodologie rigoureuse d'analyse de la biodistribution des nanoparticules de PLA a été développée. Ce qui permit, après administration par balnéation, d'en révéler le fort tropisme inné envers les cellules dendritiques muqueuses. Ces données ont servi à élaborer une stratégie de ciblage, utilisant la lectine agglutinine de cacahuète, capable d'augmenter la prise en charge des nanoparticules de PLA par les branchies et la peau. Enfin, l'étude du devenir de ces nanoparticules après injection intraveineuse, a révélé de nombreuses interactions avec le système circulatoire. Ce travail a permis d'approfondir la connaissance des interactions des nanoparticules de PLA avec le vivant, soulignant le potentiel prometteur de ces nanoparticules pour la vaccination muqueuse
Medecine shows a growing interest regarding nanobiotechnologies. Among them are poly(lactic acid) (PLA) nanoparticles, which represent a biocompatible and competent nanosystem to heighten the specificity and efficacy of diverse therapeutic and vaccine treatments, following mucosal and intravenous administration. However, the further optimization of such nanosystem is poised by the lack of informations regarding their in vivo biodistribution, especially at the cellular level.The main objective of this PhD is to increment the knowledge about PLA nanoparticles biodistribution in vivo, after muquous and intravenous administration, to further expand their optimisation and use perspectives. The zebrafish model has been utilized to perform this research because of his conserved complexity as well as his suitability for whole-organism studies.To fulfill this project, a precise methodology has been developed to analyze the PLA nanoparticles biodistribution. Which allowed, after bathing administriation, to unveil their robust innate tropism toward mucous dendritic cells. From these data has been established a targeting strategy, utilizing the peanut agglutinin lectin, which has been proved to enhance nanoparticle uptakes by both gills and skin mucosae. Finally, the study of PLA nanoparticles behavior and destiny after intravenous injection, revealed numerous elaborated interactions with the circulatory system.Overall, this work has been able to strengthen our understandings of PLA nanoparticles among living organisms, furthermore highlighting their promizing potential as nanovehicles for mucosal vaccines

L'apparition de métastases cérébrales multiples est une évolution critique de nombreux cancers avec un impact majeur sur la survie globale. Une nouvelle nanoparticule à base de gadolinium, l’AGuIX®, a récemment démontré son efficacité en tant que radiosensibilisant et agent de contraste IRM dans plusieurs études précliniques. L’objectif de cette thèse est d’établir une preuve de concept sur un modèle animal puis de réaliser la première administration chez l’homme de ce nouveau médicament dans le cadre d’un essai de phase 1.La première partie de ce travail a consisté à l’irradiation en 6 MeV après injection d’AGuIX® d’un modèle de rat Fisher porteur du gliome cérébral 9L suivi par IRM. Nous avons mis en évidence une distribution favorable des nanoparticules dans la tumeur par effet EPR (Enhanced Permeability and Retention) avec une concentration de gadolinium dans la tumeur 20 fois plus importante que dans le cerveau sain. L’effet radiosensibilisant a été démontré avec une diminution significative (p=0.02) de la taille des tumeurs dans le groupe irradié après injection d’AGuIX®. Ces résultats, associés au profil de tolérance favorable sur les modèles animaux ont motivés le transfert chez l’homme de ce nouveau médicament dans une étude de phase 1 nommée NANO-RAD (EudraCT 2015-004259-30 ; NCT02820454). Il s’agit d’une étude monocentrique, ouverte, évaluant la faisabilité et la tolérance d'AGuIX® associé à une irradiation panencéphalique (30 Gy, 10 Fr de 3 Gy) pour des patients atteints de métastases cérébrales multiples. L'objectif principal est de déterminer la dose maximale tolérée des nanoparticules avec un schéma d’escalade de dose par palier de 3 patients à 15, 30, 50, 75 et 100 mg/kg. Les objectifs secondaires sont l’étude pharmacocinétique de la distribution d'AGuIX® par IRM, de la survie sans progression intracrânienne et de la survie globale. La première administration chez l’homme a été réalisée au CHU de Grenoble le 18 juillet 2016 et le dernier patient (n=15) a été inclus le 06 février 2018. L’ensemble des lésions, quelques soit l’origine histologique (poumon, mélanome, sein) ont eu une prise de contraste d’AGuIX® dont la concentration retrouvée dans la tumeur était proportionnelle à la dose injectée. La demi-vie sanguine moyenne est de 1h09 (± 26min). La tolérance au traitement a été bonne avec une escalade de dose jusqu’à 100 mg/kg qui devient ainsi la dose retenue pour la suite des essais cliniques. Sur les 14 patients évaluables, 12 ont eu un bénéfice clinique du traitement avec une diminution du volume tumoral. Les résultats préliminaires sont prometteurs en termes de tolérance, de distribution et d’efficacité et devront être confirmés par l’étude de phase 2 multicentrique randomisée prévue pour la fin de l’année 2018
The occurrence of multiple brain metastases is a critical evolution of many cancers with a major impact on overall survival. A new gadolinium-based nanoparticle, AGuIX®, has recently demonstrated its efficacy as a radiosensitizer and MRI contrast agent in several preclinical studies. The objective of this thesis is to establish a proof of concept on an animal model and then to perform the first administration of this new drug in humans in a phase 1 trial. The first part of this work consisted of a 6 MeV irradiation after AGuIX® injection of a Fisher rat model carrying 9L cerebral gliomas assessed by MRI. A favorable distribution of nanoparticles was observed by EPR effect (Enhanced Permeability and Retention) with a concentration of gadolinium into the tumor 20 times higher than in healthy brain. The radiosensitizing effect was demonstrated with a significant decrease in tumor size (p=0.02) for the irradiated group with AGuIX® injection. These results, combined with the favorable safety profile in animal models, motivated the transfer of this new drug to humans in a Phase 1 study named NANO-RAD (EudraCT2015-004259-30; NCT02820454). This is a monocentric, open-label study evaluating the feasibility and safety of AGuIX® combined with whole brain radiation therapy (30 Gy, 10 Fr of 3 Gy) for patients with multiple brain metastases. The main objective is to determine the maximum tolerated dose of nanoparticles with a dose escalation scheme by steps of 3 patients at 15, 30, 50, 75 and 100 mg/kg. Secondary objectives are the pharmacokinetics, distribution of AGuIX® by MRI, intracranial progression-free survival and overall survival. The first human administration was performed at Grenoble University Hospital on 18 July 2016 and the last patient (n=15) was included on 06 February 2018. All metastases, whatever the histological type (lung, melanoma, breast) had a uptake of AGuIX® whose concentration in the tumor was proportional to the injected dose. The average blood half-life is 1h09 (± 26 min). Tolerance to the treatment was good with a dose escalation up to 100 mg/kg, which became the dose selected for further clinical trials. Of the 14 evaluable patients, 12 had a clinical benefit of treatment with a decrease in tumor volume. These preliminary results are promising in terms of safety, distribution and efficacy and should be confirmed by the randomized multicenter Phase 2 study planned for the end of 2018

In the latter half of the 20th century the first active environmentalist movements such as Greenpeace and the International Energy Agency were born and initiated a gradual rethinking of environmental awareness. Against all expectations the sole agency under international law for climate protection policy, called the United Nations Framework Convention on Climate Change, was formed 20 years later. Today the awareness of sustained, regenerative and environmental policies permeates throughout all areas of life, science and industry. But energy provision is the most decisive topic, especially since the discussions concerning the phase out of nuclear power where the voices calling for alternative energy sources have become much more vociferous. In addition the depletion of fossil fuels is expected to occur in the not too distant future. All new energy generation methods are required to meet the present and future energy demands, need to be ecological and need to exhibit the same or significantly lower cost expenditure than current energy sources. Unfortunately mankind is confronted with the problem that current commercial alternative energies are more expensive and not yet remotely as efficient as the present energy sources. Although energy provision based on water, wind, sun and geothermal sources have a huge potential because of their continuous presence, unfortunately, they are plagued by inefficient energy conversion caused by the state of technology i.e. the conversion of sun light into electricity loses energy through heat emission, reflection of the sun light, the inability of the material to absorb the entire sun spectrum and the ohmic losses in the transmission of electric current. The sun power is the most exhaustless resource and moreover through photovoltaic action, one of the most direct and cleanest source for use in energy conversion. Presently incoming sun light is not transformed in its entirely, as much degradation occurs during photon absorption and electron transfer processes. A number of other innovative possibilities have also been researched. With respect to cost and efficiency one of the most promising devices is injection solar cells (ISC). By dint of the dye sensitised solar cell (DSSC) Grätzels findings provided the foundations for much research into this type of solar cell where the light absorbing molecule employed in is a dye.[1] The current is obtained through charge separation in the dye, which is initiated through the connection between the dye and a metal oxide on the one hand and a matched redox couple on the other. In a variant of the DSSC the charge separation processes can also occur between a nanoporous metal oxide and nanoparticles giving rise to a quantum dot sensitised solar cell (QDSSC).[2] The use of nanoparticle (NP) properties can be utilized for the harvesting of solar energy, as demonstrated by Kamat and coworkers[3] who were able to exploit these findings subsequently and prepare a number of nanoparticle based solar cells. Nanoparticle research has comprised a wide field of science and nanotechnology for a number of years. As the size of a material approaches dimensions on the nm scale the surface properties contribute proportionally more to the sum of the properties than the volume due to the increase in the surface to volume ratio. These dimensions also constitute a threshold in which quantum physical effects need to be taken into account. Hence the properties of devices or materials in this size regime are inevitably size dependent. The basic principles can be described by two different theories, one of which is based on molecular orbital theory in which the particle is treated as a molecule. For this reason n atomic orbitals with the same symmetry and energy can build up n molecular orbitals through their linear combination based on the LCAO method (Linear Combination of Atomic Orbitals).[4] In the case of solids the orbitals build up energy bands, where the unoccupied states form the quasi continous conduction band (CB) and the occuppied states form the quasi continous valence band (VB). The energy \"forbidden\" area in between these two bands is called the band gap. The band gap is a fixed material property for bulk solids but depends on size in the case of the nanoparticles. In contrast to the LCAO method, simplified solid state theory will be used throughout the present work, the theoretical background of which is provided by the effective mass approximation.[5] When an absorption of a photon occurs, an exciton (electron-hole pair) can be generated. By promoting an electron (e-) from the valence band into the conduction band a hole (h+) may be said to remain in the valence band. By comparison to bulk solids, in a small particle the free charges can sense the potential barrier i.e. the edges of the nanoparticle. Analogous to the particle in a box model this potential barrier interaction results in an increase in the band gap as the particle size decreases. In a solar cell NPs with a particle size which possess a band gap energy in the near infrared (NIR) may be utilised and therefore the NPs will be able to absorb in this spectral region. However NPs also have the ability to absorb higher energy photons due to the continuum present in their band structure, so that almost the entire sun spectral range from the NIR up to UV wavelengths may be absorbed just by using the appropriate NP material and size. Suitable NPs are metal chalcogenides e.g. MX (where M = cadmium, zinc or lead and X = sulfur, selenium or tellurium) because of their bandgap size[6–10] and their relative band positions compared to those of the semiconductor oxide states. Both the TiO2/CdSe[11–14] and TiO2/CdTe[15–18] systems have already been successfully fabricated and many of the anomalies reported.[3] Much interest in the lead chalcogenides has been generated by reports that they may feature the possibility to exhibit multiple exciton generation (MEG) where the absorption of one high energy photon can result in more than one electron-hole pairs.[19–25] Currently electrochemical impedance spectroscopy (EIS) is being used more and more to clarify processes at polarisable surfaces and materials such as nanoparticles. Likewise this method has been rediscovered in photovoltaic research and its use in the characterisation of DSSCs has been discussed in the literature.[26–31] In a number of publications the evaluation of nanoporous and porous structures has been quite extensively explored.[28,29,32–34] Since the mid-20th century Jaffé’s[35] theoretical work concerning the steady- state ac response of solid and liquid systems lead to the formation of the basics of EIS. Further developments in the measurement technology have lead to a broader range of analysis becoming possible. Nevertheless the most challenging part still remains the interpretation of the results and especially to merge the measured data with the theoretical model. EIS quantifies the changes in a small ac current response at electrode electrolyte interfaces i.e. the rate at which the polarized domain will respond, when an ac potential is applied. In this way dielectric properties of materials or composites, such as charge transfers, polarization effects, charge recombination and limitations can be measured as a function of frequency and mechanistic information may be unveiled. Hence EIS allows one to draw a conclusion concerning chemical reactions, surface properties as well as interactions between the electrodes and the electrolyte. Other very useful tools that may be employed for quantifying electron transfer processes and their time domains are intensity modulated photocurrent spectroscopy (IMPS) and intensity modulated photovoltage spectroscopy (IMVS). IMPS permits the generation of time-resolved plots of particular photo-processes in the system, each of which may be specifically addressed through varying the excitation wavelength. For the IMPS technique a sinusoidal wave with a small amplitude is applied, analogous to that of electrochemical impedance spectroscopy, but in this case the modulation is applied to a light source and not to the electrochemical cell as in EIS.[35] The current response is associated with the photogenerated charge carriers which flow through the system and finally discharge into the circuit. The amount of generated and discharged charge carriers is often different due to the presence of recombination and capture processes in surface or trap states. Ultimately the phase shift and magnitude of these currents reveal the kinetics of such processes. The only processes that will be addressed will be those that occur in the same frequency domain or on the same time scale as that of the modulated frequency of the illuminated light. In the literature some explanation of the kinetics of simple systems can be found and basic theories and introductive disquisitions may be found elsewhere.[36–38] Furthermore in solar cell research a multiplicity of studies are available which give an account of IMPS measurements on TiO2 nanoporous structures. Such studies permitted proof for the electron trapping and detrapping mechanism in TiO2 surface states.[39,40] An analysis of TiO2 electrodes combined with a dye sensitization step was established in the work of Peter and Ponomarev.[41–43] Hickey et.al.[44,45] have previously published kinetic studies on CdS nanoparticle (NP) modified electrodes. A theory was presented which allows for the IMPS data to be the interpreted in the case of CdS NP based electrodes. The back transfer, recombination and surface states have been demonstrated to be important as was determined from their inclusion in the theory. Similar attempts to explain the kinetics of CdS quantum dots are described by Bakkers et.al.[46]. In the present work the most important questions concern the behaviour of the photovoltaic assembly. Such assemblies can be equated with an electrode in contact with an electrolyte. Preliminary remarks about such electrodes as components of an electrochemical cell will be introduced in the first part of chapter 2. Thereafter the properties of electrodes in contact with the electrolyte and under illuminated conditions are illustrated. This is followed by a description of the important electrochemical and opto-electrochemical methods which have been employed in these studies. In particular, two separate subsections are dedicated to the methods of EIS and IMPS and the experimental section which are then linked to the theoretical section. The synthesis of all substances used and the preparation of the solar cell substrates are also dealt with in this section as will the equipment used and the instrument settings employed. The optical response of the working photoactive electrode is not only dependent on the substances used but also on their arrangement and linkage. The substrate which was employed in chapter 3 consists of a nanoporous ZnO gel layer upon which an organic linker has been placed in order to connect the oxide layer with the light absorbing component, the PbS NPs. Chapter 3 deals with the linker dependence on the ZnO layer and reports the typical optical characteristics and assembly arrangements of six different linkers on the ZnO layer which is an important intermediate stage in the fabrication of an ISC. The questions concerning how the type of linking affects the photo response and other electrochemical interactions of the complete solar cell substrate will be outlined in chapter 4. Further an examination of the electrochemical and opto-electrochemical behaviours of the samples will be presented similar to that presented in chapter 3. The most interesting substrate resulting from the investigations as described in chapter 3 and 4 will be used for a more in-depth characterisation by EIS in chapter 5. A suitable model and the results of the calculation of the ISC and the intermediate stages will be presented. The potential dependence, the dependence on the illuminated wavelength and also the size dependence of the PbS nanoparticles will be discussed. It will be revealed that ZnO is chemically unstable in contact with some of the linkers. For that reason the same linker study has been repeated with the more stable TiO2 employed as the wide band metal oxide. Comparisons between the different semiconductor metal oxides are made in chapter 6. In addition a number of open questions which previously had remained unanswered due to the instability of the ZnO can now be answered. In chapter 7 another highly porous structure different from that of the ZnO gel structure has been studied to determine its suitability as an ISC substrate. The structure arises from the electrodeposition of a ZnO reactant in the presence of eosin Y dye molecules. In the end the desorption of the dye provides a substrate with a high degree of porosity. Compared to the ZnO gel which was prepared and used for measurements in chapter 3 and 4, the electrodeposited ZnO is of a higher crystallinity and possesses a more preferential orientation. This results in a lower amount of grain boundaries which in turn results in fewer trap processes and subsequently yields a higher effective diffusion of the electron through the layer.[47,48] Optical and (opto-)electrochemical methods have been used for the basic characterisation of the untreated ZnO/Eosin Y and all other materials used in the fabrication of the ISC and a comparison with the ZnO gel used in chapter 3 and 4 will be made. Finally in chapter 8 an alternative metal oxide structure will be discussed. The background to this last chapter is to examine the influence of the ISC where the oxidic layer is present as a highly periodic arrangement, known as a photonic crystal. The TiO2 metal oxide which was also used in chapter 6 has been structured to form an inverse opal. First preparative findings and the first illustration of the (opto-)electrochemical results are presented. Consequently suggestions for improvements will be made. It is envisaged that the information gathered and presented here will help to achieve a deeper understanding of solar cells and help to improve the device efficiency and the interplay of the materials. Elementary understanding paves the way for further developments which can also contribute to providing devices for more efficient energy conversion.

Im Rahmen dieser Arbeit werden die Nanopartikel mittels verschiedener Beschichtungsverfahren auf eine Zwischenoberfläche (Substrat) appliziert. Diese wird anschließend in die Kavität einer Spritzgießmaschine eingelegt, wobei es während des Spritzgießprozesses zur Übertragung der Nanopartikel auf das PC-Formteil kommt. Als Modellsystem werden dafür Goldnanopartikel (AuNP) verwendet, da diese charakteristische optische, chemische und physikalische Eigenschaften aufweisen. Im weiteren Verlauf wurde die Übertragung von Kohlenstoffnanoröhren (CNT) und Siliziumdioxidnanopartikeln (SiO2-NP) untersucht. Die Oberflächen der SiO2-NP wurden außerdem mithilfe funktioneller Alkoxysilane modifiziert, um den Einfluss der Nanopartikeloberfläche auf die Übertragung zu untersuchen.

We report visualization of spin polarized states in macroscopic ensembles of biologically-produced ferromagnetic palladium nanoparticles using the Faraday effect-based technique of magneto-optical imaging. The ferromagnetic palladium only exists in the form of nanoparticles. Large quantities of palladium nanoparticles may be synthesized via biomineralization from a Pd2+ solution. The ferromagnetic Pd nanoparticles are formed in the periplasmic space of bacteria during the hydrogen-assisted reduction of Pd2+ ions by hydrogenases. The ferromagnetism in Pd comes from itinerant electrons. A high Curie temperature of ferromagnetic palladium, about 200 degrees centigrade above room temperature, would allow for a range of room-temperature magnetic applications. The processes of the isolation of electron spins in separate nanoparticles, spin hopping, spin transport and spin correlations may even form a basis of quantum computing. So far, measurements of the magnetic properties of Pd nanoparticles (PdNP) have been limited by integral techniques such as SQUID magnetometry, magnetic circular dihroism and muon spin rotation spectroscopy ( SR). In the present study, ferromagnetic Pd nanoparticles are characterized using the technique of magneto-optical imaging. This allows visualization of the spin polarization by the variations in the intensity of polarized light. To perform measurements at relatively low magnetic fields, a spin injection from a colossal magnetoresistive material has been used. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35337

La rapamycine est un inhibiteur de mTOR actuellement utilisé comme immunosuppresseur, notamment dans le domaine des greffes. Elle inhibe la voie de signalisation mTOR entrainant la restauration de l'autophagie, processus déficient lors de la physiopathologie de l'arthrose, rendant son utilisation intéressante dans le traitement des arthropathies dégénératives. La rapamycine est cependant responsable d'effets indésirables médicamenteux systémiques notables. Pour réduire ce risque, son injection locale, au sein de l'articulation, est une alternative avantageuse. Néanmoins, cette voie d'administration a des inconvénients : le contact direct du tissu articulaire à des concentrations importantes de principe actif, sa clairance à partir de la cavité articulaire, et la difficulté d'administrer un tel composé hydrophobe. De fait, le développement de nanoparticules est une alternative séduisante pour améliorer son utilisation par voie intra-articulaire. Dans ces travaux, nous avons évalué la cytotoxicité de la rapamycine sur les cellules de l'articulation, à savoir les chondrocytes et les synoviocytes à différentes concentrations et différents temps. Nous avons observé une cytotoxicité dose-dépendante, et une sensibilité plus importante des synoviocytes par rapport aux chondrocytes. La cytotoxicité sur des cellules souches mésenchymateuses osseuses, qui sont utilisées en ingénierie articulaire, a également montré une toxicité dose-dépendante. La rapamycine à 10 µM, décrite comme retardant les lésions cartilagineuses dans l'arthrose expérimentale, n'induit pas de toxicité et permet de réduire l'effet catabolique de la MMP13 induite par l'IL-1ß sur les chondrocytes et les synoviocytes. Dans cette étude, des nanoparticules de PLGA ont été développées pour libérer de façon prolongée la rapamycine après une administration intra-articulaire à cette concentration. Elles n'ont pas été responsables de cytotoxicité sur les chondrocytes, les synoviocytes. Enfin, nous avons constaté in vivo que l'administration de 50 µL de rapamycine à 10 µM sous forme de nanoparticules par voie intra-articulaire chez le rat augmentait sa demi-vie et son temps de rétention moyen dans l'articulation comparativement à une administration locale de la forme libre, tout en diminuant sa diffusion systémique
Rapamycin is an mTOR inhibitor currently used as an immunosuppressant, particularly in the field of transplantation. It inhibits the mTOR signaling pathway leading to the restoration of autophagy, a process that is deficient in the pathophysiology of osteoarthritis, making its use interesting in the treatment of degenerative arthropathies. However, rapamycin is responsible for significant systemic adverse drug reactions. To reduce this risk, its local injection, within the joint, is an advantageous alternative. Nevertheless, this route of administration has disadvantages: direct contact of the joint tissue with high concentrations of active drug, its clearance from the joint cavity, and the difficulty of administering such a hydrophobic compound. Therefore, the development of nanoparticles is an attractive alternative to improve its use by intra-articular application. In this work, we evaluated the cytotoxicity of rapamycin on joint cells, namely chondrocytes and synoviocytes at different concentrations and different times. We observed a dose-dependent cytotoxicity, and a higher sensitivity of synoviocytes compared to chondrocytes. Cytotoxicity on bone mesenchymal stem cells, which are used in cartilage engineering, also showed dose-dependent toxicity. Rapamycin at 10 µM, described as delaying cartilage damage in experimental osteoarthritis, does not induce toxicity and reduces the catabolic effect of IL-1ß-induced MMP13 on chondrocytes and synoviocytes. In this study, PLGA nanoparticles were developed to release rapamycin in a sustained manner after intra-articular administration at this concentration. Free and rapamycin-loaded nanoparticles were not responsible for cytotoxicity on chondrocytes, synoviocytes. Finally, we found in vivo that administration of 50 µL of 10 µM rapamycin-loaded nanoparticle intra-articularly in rats increased its half-life and mean retention time in the joint, compared to local administration of the free form, while decreasing its systemic diffusion

This thesis addresses the syntheses towards high quality CdSe and CdTe nanoparticles. Therefore, thermodynamic and kinetic aspects of the hot injection method are investigated. By means of the introduction of a thermodynamically less favored nuclei species the nucleation event of CdSe quantum dot synthesis is affected. Utilizing highly reactive tin or lithium silylamides, primarily formed SnSe or Li2Se nuclei undergo a cation exchange to the demanded CdSe particles. The further growth proceeds without the incorporation of the so called quasi-seed species. In this manner, the mechanism of the cation exchange-mediated nucleation is proven and optimized with respect to the required amount of the quasi-seed species. Furthermore, this protocol is applied to up-scaling attempts to reduce the efforts for optimization to a minimum. Following this, a successful laboratory batch up-scaling is achieved by increasing flask size as well as precursor concentrations by factors of 2 and 10, respectively. A further possibility to thermodynamically influence the hot injection synthesis is the activation of the precursor species. By altering the injection pathway, as compared to the standard synthesis, the precursor species are differently coordinated and hence possess different thermodynamic stabilities. Investigations on the system of CdTe quantum dots lead to the result of a cation activation by the use of the thermodynamically less stable carboxylate ligands instead of phosphonates. Additionally, anion activation is suggested due to a kind of aging of the phosphine ligands via their oxidation by phosphonic acids. Furthermore, it is found that the ratio of Cd-to-Te strongly influences the formation of so called magic-sized clusters. Following the results, the smallest detectable species is determined as a cluster species with a size of 1.8 nm. The role of the magic-sized clusters is not fully resolved, but the initial growth is assumed to occur via monomer deposition onto or the fusion of the observed clusters. On the other hand, cluster dissolution is thermodynamically forced by the decreasing monomer concentration and can simply be explained by the process of Ostwald ripening via the creation of a smaller cluster species. Mechanistically this is explained by the formation of configurational deviations from the ideal closed-shell structure. Finally the inorganic coating of the core quantum dots in investigated. Therefore, homoepitaxial coating is employed to overcome the limit in particle size by introducing additional monomer supply. As a result, following the classical crystallization theory, defined injections of precursor material during the diffusion limited growth regime allow a fine tuning of the final particle size. Nevertheless, homoepitaxial coating inevitably leads to photoluminescence quenching, whereas heteroepitaxial growth usually improves the optical quality. By means of a type I structure, CdSe/CdS/ZnS, the successive ion layer adsoption and reaction mechanism is discussed. Furthermore, alloy structures of CdSe/ZnSe with a radially gradated intermediate shell of CdZnSe are achieved by postsynthetic high temperature treatments. This annealing induces internal diffusion processes and allows exactly adjusting the emission wavelength due to defined shrinkage of the initial core size during the alloying process.

Despite of all the research going on for the treatment of ocular diseases, age-related macular degeneration (AMD) remains one of the serious vision threatening disease worldwide. Choroidal neovascularization, a pathophysiological characteristic of wet AMD, is the growth of anomalous blood vessels in the eye choroidal layer. Neovascularization is a key factor in AMD and thus anti-angiogenic therapy is beneficial in reducing the development of new abnormal blood vessels to prevent progression of AMD. Axitinib, multi-receptor tyrosine kinase inhibitor, is a small molecule that works by blocking vascular endothelial growth factor receptors (VEGFR) and platelet derived growth factor receptors (PDGFR) responsible for developing neovascularization. Thus, goal of this study was to develop and characterise a sustained release formulation of Axitinib loaded poly (lactic-co-glycolic) acid (PLGA) nanoparticles. The nanoparticles were characterized for particle size and zeta potential as well as using DSC, TEM and in vitro drug release profile. The cytotoxicity of the formulation was evaluated on human retinal pigmented epithelium ARPE19 cells by MTT assay. The cellular uptake, anti-migration assay, and VEGF expression levels were found out in vitro using cells. The optimized formulation was 131.33 ± 31.20 nm in size with -4.63± 0.76 mV zeta potential. Entrapment efficiency was found to be 87.9 ± 2.7%. The cytotoxicity of ARPE19 cells was less than 12% for nanoparticles suggesting the in vitro compatibility at 10 µM concentration of drug. Cellular uptake, anti-migration assay and VEGF expression levels for the nanoparticles had greater uptake, had significant anti-angiogenic potential and exhibited inhibition of VEGF activity. The results showed successful development of axitinib loaded PLGA nanoparticles as an alternative potential treatment option for AMD.

In this study nanometric iron carbide particles were produced by using an induction thermal plasma reactor. There are several applications for iron carbide particles in research and industry, such as in ferrofluids, magnetic recording and biosensors. We are focused in this project on its application as catalyst for Fischer-Tropsch reaction. Two different injection methods were used in this study. Suspension injection was used because of its capability to inject heterogeneous precursors, and solid injection was used to inject reactants with any desired molar ratio. The effect of several process parameters was investigated (plate power, injection rate, probe position, particle size and reactant ratio) and composition and morphology of produced powder were characterized using several characterization techniques including X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA), and specific surface area measurement using BET method. XRD results showed that the produced powder has about 50% of iron carbide alongside other phases such as pure iron, austenite and graphite. SEM and TEM images revealed that nanometric particles with a diameter between 10-50 nm were produced alongside larger particles with diameter between 1 to 3 [micrometer]. High resolution TEM images showed that the produced nanometric particles have a core-shell structure and that they are embedded in an amorphous carbon. A new method has also been developed to collect the produced nanopowder in a liquid in order to minimize nanoparticle dispersion into the air, and protect pyrophoric nanoparticles from air exposure.

Doctor of Philosophy
Department of Chemistry
Jun Li
Solar energy as a sustainable resource is a promising alternative to fossil fuels to solve the tremendous global energy crisis. Development of three generation of solar cells has promoted the best sunlight to electricity conversion efficiency above 40%. However, the most efficient solar cells rely on expensive nonsustainable raw materials in device fabrication. There is a trend to develop cost-effective biophotovoltaics that combines natural photosynthetic systems into artificial energy conversion devices such as dye sensitized solar cells (DSSCs). In this research, a model system employs natural extract light-harvesting complex II (LHCII) as a light-absorbing sensitizer to interface with semiconductive TiO₂ and plasmonic nanoparticles in DSSCs. The goal of this research is to understand the fundamental photon capture, energy transfer and charge separation processes of photosynthetic pigment-protein complexes along with improving biophotovoltaic performance based on this model system through tailoring engineering of TiO₂ nanostructures, attaching of the complexes, and incorporating plasmonic enhancement. The first study reports a novel approach to linking the spectroscopic properties of nanostructured LHCII with the photovoltaic performance of LHCII-sensitized solar cells (LSSCs). The aggregation allowed reorganization between individual trimers which dramatically increased the photocurrent, correlating well with the formation of charge-transfer (CT) states observed by absorption and fluorescence spectroscopy. The assembled solar cells demonstrated remarkable stability in both aqueous buffer and acetonitrile electrolytes over 30 days after LHCII being electrostatically immobilized on amine-functionalized TiO₂ surface. The motivation of the second study is to get insights into the plasmonic effects on the nature of energy/charge transfer processes at the interface of photosynthetic protein complexes and artificial photovoltaic materials. Three types of core-shell (metal@TiO₂) plasmonic nanoparticles (PNPs) were conjugated with LHCII trimers to form hybrid systems and incorporated into a DSSC platform built on a unique open three-dimensional (3D) photoanode consisting of TiO₂ nanotrees. Enhanced photon harvesting capability, more efficient energy transfer and charge separation at the LHCII/TiO₂ interface were confirmed in the LHCII-PNP hybrids, as revealed by spectroscopic and photovoltaic measurements, demonstrating that interfacing photosynthesis systems with specific artificial materials is a promising approach for high-performance biosolar cells. Furthermore, the final study reveals the mechanism of hot electron injection by employing a mesoporous core-shell (Au@TiO₂) network as a bridge material on a micro-gap electrode to conduct electricity under illumination and comparing the photoconductance to the photovolatic properties of the same material as photoanodes in DSSCs. Based on the correlation of the enhancements in photoconductance and photovoltaics, the contribution of hot electrons was deconvoluted from the plasmonic near-field effects.

L’étude des propriétés singulières de nanoparticules colloïdales synthétisées par voie chimique et leur intégration dans des nano-composants requiert leur assemblage dirigé sur des zones parfaitement définies et localisées de surfaces solides. L’objet de cette thèse est le développement d’une méthode d’assemblage dirigé originale: la nanoxérographie par microscope à force atomique (AFM). Cette technique consiste à injecter localement, sur des zones spécifiques, des charges électrostatiques dans un matériau électret par l’intermédiaire d’une pointe d’AFM. Ces charges servent ensuite de pièges électrostatiques sur la surface pour les nanoparticules en solution. Dans le cadre de ce travail, l’injection, la rétention de charges dans de fines couches électrets de PolyMéthylMéthAcrylate (PMMA) et la quantification des densités de charges surfaciques des motifs chargés, ont été étudiées grâce au mode électrique dérivé de l’AFM, le microscope à force Kelvin (KFM). L’étude de l’assemblage de nanoparticules de différentes natures (métal, polymère (organique ou inorganique)), de taille moyenne variable dans un large domaine (2 nm - 1µm) et de potentiel zêta contrôlé a permis d’analyser les mécanismes de dépôt et de montrer les performances de la méthode et son aspect générique. Enfin deux techniques d’injection de charges parallèles ont été mises en place afin d’offrir des perspectives industrielles: le microcontact printing électrique et la nanoimpression électrique
The study of original properties of colloidal nanoparticles and their integration into nanodevices requires their assembly onto specific areas of solid surfaces. The aim of this thesis work is to develop an innovative method for the directed assembly of colloidal nanoparticles: the nanoxerography process by atomic force microscope (AFM). This technique consists in injecting charges into electrets using an AFM tip. The injected charges are then used to electrostatically trap nanoparticles from suspensions onto the surface. In this context, the charge writing and charge decay in PolyMethyMethAcrylate (PMMA) thin films were studied and the charge density of the charged patterns were quantified using Kelvin force microscope (KFM), an electrical mode of AFM. Assemblies of nanoparticles of different nature (metallic, polymeric (organic and inorganic)), with average sizes extending over a large range (2 nm to 1 µm) and controlled zeta potential were obtained on PMMA thin films. This allowed the analysis of assembly mechanisms and demonstration of the excellent performance of the method. Finally, two techniques of parallel charge writing, viz., the electrical microcontact printing and the electrical nanoimprinting were explored with the prospect of extending the nanoxerography process to industrial scale

Les nanoparticules d'argent, déjà largement utilisées en catalyse, optique et électronique, trouvent aujourd'hui de nouvelles applications comme l'imagerie, la photonique ou la détection chimique et biochimique. Parmi ces applications, certaines requièrent des morphologies particulières comme des bâtonnets ou des disques (films conducteurs, spectroscopie Raman exaltée) quand d'autres impliquent principalement une surface spécifique importante comme par exemple en catalyse hétérogène. Les nanoparticules métalliques anisotropes sont classiquement réalisées en deux étapes, séparant la formation des germes et la croissance de ceux-ci, afin de mieux en contrôler la morphologie mais la séparation en deux étapes rend le transfert à l'échelle industrielle délicat à cause des longues périodes d'incubation et de lavage nécessaires. Nous avons choisi de nous intéresser à la synthèse dirigée de nanoparticules anisotropes, en particulier des nanodisques d'argent, ainsi que leur assemblage, en solution et sur des surfaces. Dans nos travaux, nous avons retenu une approche permettant de réaliser les deux étapes de la formation de nanodisques d'argent dans un même milieu réactionnel. Le principe repose sur l'utilisation de deux réducteurs, l'un faible et l'autre fort, dont les cinétiques de réduction très différentes permettent le contrôle de l'anisotropie. Cette méthode est simple et permet de réduire le temps de synthèse mais nécessite un bon contrôle des différents paramètres expérimentaux. Le temps entre l'ajout des deux réducteurs détermine notamment la morphologie des objets formés. Il existe en réalité une gamme optimale pour ce temps qui dépend particulièrement de la température de la synthèse. Afin de faire varier les propriétés optiques de ces nanodisques, différentes stratégies peuvent être envisagées. Notre choix s'est tourné vers la formation d'assemblages, en solution dans un premier temps, puis sur des surfaces par des méthodes de dépôt. L'adsorption de molécules organiques bifonctionnelles peut permettre de réaliser des assemblages en solution : une des fonctions a une affinité avec l'argent et l'autre interagit avec les fonctions libres des autres nanoparticules grâce à des liaisons hydrogène ou électrostatiques par exemple. Les assemblages peuvent également être réalisés sur des surfaces. Nous nous sommes tournés vers des méthodes de dépôts originales, qui permettent des assemblages dirigés des nanodisques par voie électrostatique. Nous avons démontré que ces assemblages sont de bons candidats pour développer des substrats SERS micro-structurés
Silver nanoparticles, used extensively in catalysis, optics and electronics, are now emerging in new applications such as imaging, photonics or chemical and biochemical detection. Among these applications, some require particular morphologies such as rods or disks (conductive films, enhanced Raman spectroscopy) while others mainly involve a large specific surface area such as in heterogeneous catalysis. Anisotropic metal nanoparticles are traditionally produced in two stages, separating the formation of seeds and their growth, in order to better control their morphology. However, the two-stage synthesis makes the transfer on industrial scale difficult because of the long incubation time and the washing steps required. In this context, we decided to focus on the synthesis of anisotropic nanoparticles, in particular silver nanodisks, as well as their assembly in solution and on surfaces. In our work, we adopted an approach that allows to carry out the two stages of the formation of silver nanodisks in the same reaction medium. The principle is based on the use of two reducers, one weak and one strong, with different kinetic reduction rates, allowing the control of anisotropy. This method is simple and fast but requires good control of the experimental parameters. The time between the addition of the two reducers determines the morphology of the formed objects. There is actually an optimal range for this time, which depends particularly on the temperature of the synthesis. In order to vary the optical properties of these nanodisks, different strategies can be considered. We chose to form assemblies both in solution and on surfaces by different deposition techniques. The adsorption of bifunctional organic molecules can provoke the formation of assemblies in solution: one function has an affinity with silver and the other interacts with the free functions of the other nanoparticles through hydrogen or electrostatic bonds for example. Assemblies can also be made on surfaces. We have been working on original deposition method, which allow an oriented assembly of nanodisks through electrostatic forces.We have demonstrated that these assemblies are good candidates for developing micro-structured SERS substrates

Knowledge of the relationship between in vivo contrast agent concentration and magnetic resonance (MR) signal response is an important requirement in contrast enhanced MR imaging in general and in MR based perfusion imaging in particular. This relationship is a complex function of the properties of the contrast agent as well as the structure of the target tissue. The aim of the present work was to quantify the effects of the iron oxide nanoparticle based intravascular contrast agent, NC100150 Injection, on proton relaxation rates in different tissue systems in vivo in a pig model and ex vivo in phantoms containing whole blood. Methods that enabled accurate relaxation rate measurements in these organs were developed, and validated. From these measurements, trans-compartmental water exchange rates and blood volume could be estimated and the MR signal response could be predicted as a function of contrast agent concentration under relevant imaging conditions.

Using a 1.5 Tesla clinical MR system, the longitudinal (R₁=1/T₁) proton relaxation rates in blood, renal cortex, paraspinal muscle and myocardium were measured in vivo as a function of plasma concentration (C_p) of NC100150 Injection. The transverse (R₂^* = 1/T₂^*) relaxation rates were measured in vivo in blood, renal cortex and muscle as a function of C_p and ex vivo in blood as a function of C_p and blood oxygenation tension. The proton nuclear MR (NMR) linewidth and lineshape were analysed as a function of C_p and blood oxygen tension ex vivo at 7.05 T.

In muscle and renal cortex, there was a linear correlation between R₂^* and C_p whereas R₂^* increased as a quadratic function of C_p in blood. The NMR linewidth increased linearly with C_p in fully oxygenated blood whereas in deoxygenated blood the linewidth initially decreased with increasing Cp, reaching a minimum and then increasing again with further increase in C_p. R₁ increased linearly with C_p in blood and from the slope of R₁ vs. C_p the T₁-relaxivity (r₁) of NC100150 Injection in blood at 1.5 T was estimated to be (mean ± SD) 13.9 ± 0.9 s^-1mM^-1. In tissue, the maximum increase in R₁ was limited by the rate of water exchange between the intravascular and interstitial tissue compartments. Using a two-compartment exchange-limited relaxation model, the permeability surface area (PS) product was estimated to be 61.9 ± 2.9 mL/min/g in renal cortex and 10.1 ± 1.5 mL/min/g in muscle and the total myocardial water exchange rate, kt, was 13.5 ± 6.4 s^-1. The estimated blood volumes obtained from the same model were 19.1 ± 1.4 mL/100 g, 2.4 ± 1.4 mL/100 g and 11.2 ± 2.1 mL/100 g, respectively in renal cortex, muscle and myocardium.

Current T₂^* based first-pass MR perfusion methods assume a linear correlation between R₂^* and C_p both in blood and tissue and our results therefore suggest that quantitative perfusion values can not easily be obtained with existing tracer kinetic models. The correlation between MR signal response and C_p is further complicated in the kidney by a significant first-pass increase in R₁ which may lead to an underestimation of C_p. In T₁-based perfusion methods, low concentrations of NC100150 Injection must be used in order to maintain a linear dose-response relationship between R₁ and C_p. The effect of blood oxygenation on the NMR linewidth in the presence of NC100150 Injection enabled accurate estimation of magnetic susceptibility of deoxyhemoglobin and the effect can potentially be used to determine blood oxygenation status.

In conclusion, NC100150 Injection is well suited as a T₂^* perfusion agent due to the large magnetisation and intravascular biodistribution of this agent. T₁-based perfusion imaging with this agent is limited by water exchange effects and large T₂^* effects at higher contrast agent concentrations. Quantitative perfusion assessment is unlikely to be feasible with any of these approaches due to the non-linear dose response.

Ce travail a porté sur la séparation photo-induite intramoléculaire des charges dans des systèmes bisporphyriniques et sur la sensibilisation de semi-conducteur de type « p » pour la photovoltaïque. Le premier volet concerne la synthèse de dyades comportant un donneur d’électron relié à un accepteur par un long connecteur -conjugué. Dans ces dyades, le donneur peut être une porphyrine ou une phtalocyanine de zinc et l’accepteur peut être une porphyrine d’or ou une porphyrine d’étain. Le donneur et l’accepteur d’électron sont couplés électroniquement, ce qui permet un transfert d’électron photo-induit en une seule étape et sur une grande distance. L’étude photophysique de ces systèmes révèle une séparation des charges très rapide et une recombinaison plus lente. Dans le deuxième volet, de nouveaux sensibilisateurs dérivés du pérylène imide sont greffés à la surface de films d’oxyde de nickel. L’excitation lumineuse de ces sensibilisateurs déclenche l’injection ultra rapide d’une lacune électronique dans la bande de valence du semi-conducteur. Des cellules basées sur ce type de sensibilisation ont montré des performances photovoltaïques prometteuses
This work deals with photo-induced intramolecular charge separation in bisporphyrinic systems and with the sensitization of p-type semi-conductor for photovoltaic. The first section concerns the synthesis of dyads containing an electron donor and an acceptor connected with a long -conjugated spacer. In these dyads, the donor can be a zinc porphyrin or zinc phthalocyanine and the acceptor can be a gold porphyrin or tin porphyrin. These electronically coupled donor-acceptor systems perform single step a long-range photo-induced electron transfer over nanometer scale. The photophysical study reveals a very fast charge separation and a slower back recombinaison. In the second section, new sensitizers based on perylene unit were grafted on the nickel oxide nanoparticules. The light excitation of sensitizer induces a fast hole injection into the semi-conductor’s valence band. The solar cells based on the sensitization of nickel oxide exhibit promising photovoltaic performances

Ce travail porte sur l’étude du procédé de projection plasma par voie liquide et en particulier sur l’interaction entre la phase liquide et l’écoulement de plasma. Différents phénomènes physiques ont lieu comme la fragmentation du jet, l’évaporation du liquide et la fusion des particules. La simulation numérique permet de mieux comprendre les phénomènes physiques et vient en appui des expériences qui sont parfois difficiles voire impossibles à réaliser. Un modèle compressible diphasique est développé afin de prendre en compte les effets compressibles du plasma. Des validations sont réalisées sur des cas test académiques et sur un jet d’argon pur. De bons accords sont obtenus entre les simulations et la théorie ou les expériences. Ensuite différents mélanges de gaz plasmagènes, classiquement utilisés en projection plasma, sont étudiés : l’argon/hydrogène et l’argon/hélium.Une analyse du caractère instationnaire et turbulent est ensuite menée et permet de voir l’importance des effets instationnaires dans ces écoulements. Puis des simulations de l’injection de la phase liquide sous forme de gouttes ou de jet continu dans l’écoulement de plasma sont réalisées. L’influence de la nature des gaz plasmagènes et du mode d’injection est démontrée. Les structures observées expérimentalement sont également obtenues parles simulations
The study of the plasma spraying process is investigated in this work, in particular the interaction between a liquid phase and a plasma flow. Different physical phenomena occureas the jet fragmentation, the liquid vaporization and the particles fusion. The numerical simulation is used to better understand the physical phenomena and is an alternative to experimental measurements, which could be locally difficult to perform because of the measurement techniques limitations and the particular characteristics of the plasma. A compressible two-phase model is developped to take into account the compressible effects of the plasma flow. Validations are realized on academic test cases and on a argonjet. Good agreements are obtained between simulations and theory or experiments. Then different mixtures of plasmagen gas, classically used in plasma spraying, are studied :argon/hydrogen and argon/helium. An analysis of unsteady and turbulent character isled and allows seeing the importance of unsteady effects in these flows. Numerical simulations of the injection of a liquid phase into the plasma flow are realized. The influence of the plasmagen gas nature and the injection type is anlysed. Structures observed by experiments are also obtained by the simulations

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To evaluate the safety of single intravitreal injection of 0,1ml of sunitinib (one group with 1mg/ml and the other group with 10mg/ml), 0,1ml of a solution containing solid lipid nanoparticles and 0,1ml of a solution containing nanocapsules analyzing the possible toxic effects by the electrophysiology and histology in the albino rabbits retina. An experimental controlled study was performed with 20 eyes of albino rabbits. It were performed intravitreal injections of 0,1ml (1mg/ml) of sunitinib in 5 eyes, 0,1ml (10mg/ml) of sunitinib in 5 eyes, 0,1ml of nanocapsules solution in 5 eyes and 0,1ml of a solution containing solid lipid nanoparticles in 5 eyes. Contralateral eye did not receive any treatment and was used as control. Changes in electroretinography were not observed in groups of sunitinib (1mg/ml and 10mg/ml) and in the group of solid lipid nanoparticles. However, in the group of the nanocapsules significant changes were found. They were in the morphology and at the electroretinogram. At histological study only the group of nanocapsules degenerative changes were detected. Changes were severe edema and formation of cytoplasmic vacuoles, suggesting retinal toxicity.
O presente estudo teve por objetivo avaliar a segurança da injeção intravítrea de 0,1ml de sunitinibe (um grupo com 1mg/ml e o outro grupo com 10mg/ml), 0,1ml de solução contendo nanocápsulas e 0,1ml de solução contendo nanopartículas lipídicas sólidas analisando os possíveis efeitos tóxicos à retina de coelhos albinos detectados pela eletrofisiologia e histologia por microscopia óptica. Foi realizado estudo experimental, com 20 olhos de coelhos albinos, nos quais foram realizadas injeções intravítreas de 0,1ml (1mg/ml) de sunitinibe (5 olhos), 0,1ml (10mg/ml) de sunitinibe (5 olhos), 0,1ml de solução contendo nanocápsulas (5 olhos) e 0,1ml de solução contendo nanopartículas lipídicas sólidas (5 olhos). Os olhos adelfos não receberam injeção e foram utilizados com o controle. Não foram observadas alterações eletrorretinográficas nos grupos do sunitinibe (1mg/ml e 10mg/ml) e no grupo das nanopartículas lipídicas sólidas. No grupo das nanocápsulas houveram alterações significativas tanto na morfologia quanto na amplitude e tempo das ondas do eletrorretinograma. Ao estudo histológico, somente o grupo das nanocápsulas apresentou alterações degenerativas (núcleos tumefeitos) com acentuado edema e formação de vacúolos citoplasmáticos, sugerindo toxidade retiniana.

Novos eletrodos modificados com nanopartículas de hidróxido misto de níquel e chumbo, foram desenvolvidos para serem empregados em Análises por Injeção em Batelada (BIA) com detecção amperométrica, tendo em vista aplicações analíticas. Para esta abordagem foi obtido o hidróxido de níquel e chumbo pelo processo de solgel, em uma proporção 75 25 % (Ni-Pb, respectivamente). Este novo material foi caracterizado por microscopia eletrônica de varredura, análise termogravimétrica, e difração de raios-X. Os resultados obtidos foram consistentes com a forma polimórfica do hidróxido e com a adequada formação do material misto. Foi confirmada a composição (75/25, Ni/Pb) por espectrometria óptica de emissão por plasma acoplado indutivamente e por espectrometria de fotoelétrons excitados por raios-X. As análises eletroquímicas do α-Ni0.75Pb0.25(OH)2 confirmaram uma maior estabilidade deste hidróxido misto quando comparado com o Ni(OH)2, além de uma maior reversibilidade eletroquímica. Foram desenvolvidos eletrodos modificados com as nanopartículas de α-Ni0.75Pb0.25(OH)2 empregando diferentes suportes condutivos, o primeiro, óxido de estanho dopado com flúor (FTO) e segundo o grafite para preparar eletrodos de pasta de carbono (CPE). Por impressão 3D foram elaboradas células eletroquímicas BIA, de 4 mL de volume máximo, especialmente construídas para cada tipo de eletrodo. O método BIA empregando os eletrodos desenvolvidos mostrou ser adequado para análises, obtendo sinais de corrente estáveis e com rápida dispersão. Eletrodos de FTO modificados com α-Ni0.75Pb0.25Novel modified electrodes with nanoparticles of nickel and lead mixed hydroxide were prepared for the use in Batch Injection Analyses (BIA) coupled to amperometric detection targeting analytical applications. For this, a nickel and lead mixed hydroxide was obtained using the sol-gel process, in a proportion 75-25% (Ni-Pb). This new material was characterized by scanning electron microscopy, thermogravimetric analysis and X-ray diffraction. The obtained results are in agreement with the polymorphic form of the Ni(OH)2 and the appropriate formation of the mixed hydroxide. The composition was confirmed (75/25, Ni/Pb), employing inductively coupled plasma optical emission spectrometry and X-ray photoelectron spectroscopy. The electrochemical analysis of α-Ni0.75Pb0.25 (OH)2 support the major stability of this mixed hydroxide in comparison with Ni(OH)2 and an improve on the electrochemical reversibility. Modified electrodes were prepared with nanoparticles of Ni0.75Pb0.25 (OH)2 using different conducting supports, first fluorine doped tin oxide (FTO) and second graffiti for preparation of carbon paste electrodes (CPE). 3D printing was employed to fabricate an electrochemical BIA cell, of 4 mL of maximum capacity, for each electrode. BIA method using the developed electrodes proved to be suitable for analysis, good current response, stable and with fast dispersion were obtained. FTO electrodes modified with α-Ni0.75Pb0.25 (OH)2 were satisfactorily employed in analysis of pharmaceutical samples of piroxicam. The amperometric response of piroxicam present a linear range of 1 10-5 to 2 10-4 mol L-1 and a good analytical frequency (140 samples per hour). Detection and quantification limits were of 2.43 10-6 mol L-1 and 8.09 10-6 mol L-1. Carbon paste electrodes were prepared by modifying the pasta matrix with the nanoparticles of powder α-Ni0.75Pb0.25 (OH)2. This electrode presents a good response for glucose, a linear range of 1 10-5 to 4 10-4 mol L-1 was obtained. An analytical frequency of 200 samples per hour was achieved with a standard deviation of 2.05%. The detection and quantification limits reached were of 1.3 10-6 e 4.4 10-6 mol L-1.

Nesta tese foram desenvolvidos sensores amperométricos baseados em porfirinas supramoleculares e hidróxido de níquel nanoestruturado e estabilizado na fase alfa, bem como novos materiais baseados em hidróxidos mistos de níquel e cobalto nanoetruturados e estabilizados na fase alfa. Também, um analisador FIA amperométrico, foi desenvolvido em colaboração com o Laboratório de Instrumentação Analítica do IQ-USP, para a determinação e quantificação de SO2 livre em amostras reais, como vinhos, águas de coco e sucos de frutas. Os sensores amperométricos baseados em porfirinas supramoleculares foram empregados na determinação de SO2 livre, presente em sucos de frutas e águas de coco, utilizando um sistema FIA amperométrico. O sistema FIA amperométrico foi constituído de um injetor manual, uma cela amperométrica em fluxo integrada a uma unidade de difusão de gases e um fluxo de uma solução de ácido sulfúrico e de uma solução de eletrólito. Possíveis interferentes como ácido ascórbico, catecol, glicose e benzoato de sódio foram avaliados antes de iniciar as análises das amostras reais. Os resultados das análises foram comparados com o método oficial Monier-Williams. Os níveis de SO2 livre encontrados nas amostras estavam de acordo com o que é preconizado pela Legislação Brasileira. Os eletrodos de FTO, modificados com hidróxido de níquel estabilizado na fase alfa, foram utilizados como sensores amperométricos para a determinação de glicose, usando um sistema FIA amperométrico. Estes sensores apresentaram excelentes respostas lineares em concentrações inferiores a 100 µM. Ainda estes sensores têm apresentado uma sensibilidade específica muito elevada para a glicose, provavelmente associada com a sua natureza nanoestruturada, e consequêntemente sua área superficial aumentada. No entanto o eletrodo modificado apresentou uma tendência de mudar de fase, da fase meta-estável alfa para a fase termodinamicamente estável beta, com o aumento da concentração de glicose. Novos materiais baseados em hidróxidos mistos de níquel e cobalto estabilizados na fase alfa também foram desenvolvidos. A partir de técnicas como difratometria de raio-x e Microbalança Eletroquímica de Cristal de Quartzo (MECQ) foi possível determinar a fase polimórfica dos materiais. Técnicas como AFM e MEV demonstraram que estes materiais são formados por nanopartículas com tamanhos de 5 nm. Estes nanomateriais apresentaram uma maior quantidade de carga específica, em comparação com o hidróxido de níquel puro. E por último um analisador FIA amperométrico automatizado foi desenvolvido para a realização de análises de SO2 livre em amostras líquidas. Este analisador é composto por reservatórios de soluções, sistema de amostragem, sistema de propulsão das soluções, cela FIA amperométrica integrada a uma unidade de difusão de gases, um sensor amperométrico, além de placas controladoras, mini-potenciostato e um software para controlar o equipamento. Uma elevada reprodutibilidade foi alcançada para análises sequenciais de uma amostra, mas quando a amostra foi trocada a reprodutibilidade foi muito baixa, sendo necessário mais desenvolvimento do sistema FIA automatizado nesta área.
New nanomaterials based on mixed nickel and cobalt hydroxides stabilized in the alpha phase, as well as amperometric sensors based on supramolecular porphyrins and stabilized alpha nickel hydroxide were developed in this thesis. An amperometric FIA sulfite analyzer was also developed in colaboration with of Group of Analytical Instrumentation of IQ-USP, for determination of free SO2 present in liquid samples such as wine, coconut water and fruit juices. The amperometric FIA system is constituted by manual injector, amperometric FIA cell with integrated gas diffusion unit and amperometric sensor based on supramolecular porphyrins, whereas sulfuric acid and electrolyte were used as reactive and carrier solution. Some species such as ascorbic acid, cathecol, glucose and sodium benzoate were evaluated as possible interferents before starting the analyses of real samples. The results were compared with those obtained with the official Monier-Williams method. The concentrations of free SO2 found in fruit juices and coconut water were in accordance with Brazilian law. The amperometric FIA sensors for determination of glucose were based on FTO electrodes modified stabilized alpha nickel hydroxide, which presented excellent linear responses at concentrations below 100 µM. These sensors have shown a very high specific sensitivity for glucose probably associated with their nanostructured nature, and consequent enhanced surface area. Nevertheless, the electrode material was shown to have an increasing tendency to change from alpha to the beta phase as function of the glucose concentration. New materials based on mixed nickel and cobalt hydroxides, stabilized in the alpha phase was prepared and characterized by techniques such as X-ray diffraction, thermogravimetric analysis and Electrochemical Quartz Crystal Microbalance to determine their polymorphic phase. The nanostructured nature of the mixed nickel and cobalt hydroxide materials was confirmed by microscopy techniques such as AFM and SEM. These new materials showed a high specific charge, in fact higher than of nanostructured stabilized alpha nickel hydroxide. An amperometric FIA sulfite analyzer system for liquid samples consisting of solution reservoirs, a sampling system, a solution propulsion system, an amperometric FIA cell with integrated gas diffusion unit, an amperometric sensor based on supramolecular porphyrins, in addition to controller boards, a mini-potentiostat and control software, was developed and tested for determination of free SO2. High reproducibility was achieved for sequential analyses of a sample but the reproducibility after exchange of samples was relatively low, needing further developments in the sampling system.

Fractured viscous oil resources hold great potential for continued oil production growth globally. However, many of these resources are not accessible with current commercial technologies using steam injection which limits operations to high temperatures. Several steam-solvent processes have been proposed to decrease steam usage, but they still require operating temperatures too high for many projects. There is a need for a low temperature injection strategy alternative for viscous oil production. This dissertation discusses scoping experimental work for a low temperature solvent injection strategy targeting fractured systems. The strategy combines three production mechanisms – gas-oil gravity drainage, liquid extraction, and film gravity drainage. During the initial heating period when the injected solvent is in the liquid phase, liquid extraction occurs. When the solvent is in the vapor phase, solvent-enhanced film gravity drainage occurs. A preliminary simulation of the experiments was developed to study the impact of parameter uncertainty on the model performance. Additional work on reducing uncertainty for key parameters controlling the two solvent production mechanisms will be necessary. In a natural fracture network, the solvent would not be injected uniformly throughout the reservoir. Preferential injection into the higher conductivity fracture areas would result in early breakthrough leaving unswept areas of high oil saturation. Conformance control would be necessary to divert subsequent solvent injection into the unswept zones. A variety of techniques, including polymer and silica gel treatments, have been designed to block flow through the swept zones, but all involve initiating gelation prior to injection. This dissertation also looks at a strategy that uses the salinity gradient between the injected silica nanoparticle dispersion and the in-situ formation water to trigger gelation. First, the equilibrium phase behavior of silica dispersions as a function of sodium chloride and nanoparticle concentration and temperature was determined. The dispersions exhibited three phases – a clear, stable dispersion; gel; and a viscous, unstable dispersion. The gelation time was found to decrease exponentially as a function of silica concentration, salinity, and temperature. During core flood tests under matrix and fracture injection, the in-situ formed gels were shown to provide sufficient conductivity reduction even at low nanoparticle concentration.
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碩士
國立臺灣大學
應用物理所
100
The motivation of this thesis is to compare the performance of the degree of circularly polarized light between conventional thin film spin-LED and nanorod spin-LED. In our experiment, we compare the degree of circularly polarized light for the thin film and nanorod spin-LEDs, which is composed of InGaN/GaN multiple quantum wells, under an external magnetic field by photoluminescence and electroluminescence. We also deposit the Fe3O4 nanoparticles into the space between nanorods in order to enhance the degree of circularly polarized light arising from nanorod spin-LED. The quantum confined stark effect will gradually vanish and confined potential will become more symmetric as the thin film multiple quantum wells are etched into the nanorod structure. Thus the spin coherent time will become longer in quantum well. In addition, the efficiency of spin valve will increase after the deposition of Fe3O4 nanoparticles. Due to the increment for both the spin coherence time and efficiency of spin valve, our results show that the degree of circularly polarized light of the nanorod spin-LED with Fe3O4 nanoparticles under low external magnetic field and room temperature can be more than 10%. Its excellence performance and practical working condition make nanorod spin-LED becomes a potential spin device.

碩士
長庚大學
化工與材料工程學系
100
The screen printing electrode (SPE) has been of great interests recently. In this study, we use the SPE with the help of a flow injection system to study the effects of nanomaterials on biosensing. In the first part of our study, graphene nanoribbons are used for the electrochemical detection of ascorbic acid, dopamine and uric acid. In the second part of our study, the optimized copper oxide/graphene nanocomposites are applied for sensing of glucose. In comparison with traditional electrochemical measurements, we found that the better results can be obtained in terms of the coefficient of the sensitivity and detection limit. Therefore, it is crucial to develop a high-performance and lost cost biosensor system based on SPE.

This study presents the results of nano-particle and surfactant-stabilized solvent-based emulsion core flooding studies under laboratory conditions that investigate the recovery mechanisms of chemical flooding in a heavy oil reservoir. In the study, bench tests, including the phase behavior test, rheology studies and interfacial tension measurement are performed and reported for the optimum selecting method for the nano-emulsion. Specifically, nano-emulsion systems with high viscosity have been injected into sandstone cores containing Alaska North Slope West Sak heavy oil with 16 API, which was dewatered in the laboratory condition. The experiment results suggest that the potential application of this kind of emulsion flooding is a promising EOR (enhanced oil recovery) process for some heavy oil reservoirs in Alaska, Canada and Venezuela after primary production. Heavy oil lacks mobility under reservoir conditions and is not suitable for the application of the thermal recovery method because of environmental issues or technical problems. Core flooding experiments were performed on cores with varied permeabilities. Comparisons between direct injection of nano-emulsion systems and nano-emulsion injections after water flooding were conducted. Oil recovery information is obtained by material balance calculation. In this study, we try to combine the advantages of solvent, surfactant, and nano-particles together. As we know, pure miscible solvent used as an injection fluid in developing the heavy oil reservoir does have the desirable recovery feature, however it is not economical. The idea of nano-particle application in an EOR area has been recently raised by researchers who are interested in its feature-reaction catalysis-which could reduce in situ oil viscosity and generate emulsion without surfactant. Also, the nano-particle stabilized emulsions can long-distance drive oil in the reservoir, since the nano-particle size is 2-4 times smaller than the pore throat. In conclusion, the nano-emulsion flooding can be an effective enhancement for an oil recovery method for a heavy oil reservoir which is technically sensitive to the thermal recovery method.

Im Rahmen dieser Arbeit werden die Nanopartikel mittels verschiedener Beschichtungsverfahren auf eine Zwischenoberfläche (Substrat) appliziert. Diese wird anschließend in die Kavität einer Spritzgießmaschine eingelegt, wobei es während des Spritzgießprozesses zur Übertragung der Nanopartikel auf das PC-Formteil kommt. Als Modellsystem werden dafür Goldnanopartikel (AuNP) verwendet, da diese charakteristische optische, chemische und physikalische Eigenschaften aufweisen. Im weiteren Verlauf wurde die Übertragung von Kohlenstoffnanoröhren (CNT) und Siliziumdioxidnanopartikeln (SiO2-NP) untersucht. Die Oberflächen der SiO2-NP wurden außerdem mithilfe funktioneller Alkoxysilane modifiziert, um den Einfluss der Nanopartikeloberfläche auf die Übertragung zu untersuchen.

碩士
國立交通大學
材料科學與工程學系
100
CuInS2 nanoparticles were prepared by injecting the sulfur which had been dissolved in the oleylamine (S-OLA) into the hot oleylamine solution containing copper(I) chloride (CuCl) and indium(III) chloride (InCl3). By adjusting the reactive temperature and time of hot-injection process, CuInS2 nanoparticles about 10 nm in size were successfully formed at 180?aC for 1 hr. X-ray diffraction analysis revealed that the wurtzite phase is suppressed by decreasing the reactive temperature and the crystallinity of chalcopyrite phase improves with the increase of reactive time. The CuInS2 nanoparticles were consequently dispersed in toluene to form the ink for preparing the CuInS2 thin films on the glass subatrate via the dipping-coating process. It was found that the CuInS2 content of ink is crucial to the film quality. Moreover, the incorporation of cyclohexanone was found to improve the wetting property of ink on glass subatrate, which benefits the preparation of uniform and crack-free CuInS2 films. Post annealing study indicates the heat treatments in Ar or vacuum ambient result in the formation of In2O3 phase in thin-film samples and the annealing in Ar+10%H2 ambient is able to eliminate such an undesired oxide phae in CuInS2 thin films. However, further study is required since the carrier concentration of CuInS2 film was still high and impratical for solar cell device fabrication.

In the latter half of the 20th century the first active environmentalist movements such as Greenpeace and the International Energy Agency were born and initiated a gradual rethinking of environmental awareness. Against all expectations the sole agency under international law for climate protection policy, called the United Nations Framework Convention on Climate Change, was formed 20 years later. Today the awareness of sustained, regenerative and environmental policies permeates throughout all areas of life, science and industry. But energy provision is the most decisive topic, especially since the discussions concerning the phase out of nuclear power where the voices calling for alternative energy sources have become much more vociferous. In addition the depletion of fossil fuels is expected to occur in the not too distant future. All new energy generation methods are required to meet the present and future energy demands, need to be ecological and need to exhibit the same or significantly lower cost expenditure than current energy sources. Unfortunately mankind is confronted with the problem that current commercial alternative energies are more expensive and not yet remotely as efficient as the present energy sources. Although energy provision based on water, wind, sun and geothermal sources have a huge potential because of their continuous presence, unfortunately, they are plagued by inefficient energy conversion caused by the state of technology i.e. the conversion of sun light into electricity loses energy through heat emission, reflection of the sun light, the inability of the material to absorb the entire sun spectrum and the ohmic losses in the transmission of electric current. The sun power is the most exhaustless resource and moreover through photovoltaic action, one of the most direct and cleanest source for use in energy conversion. Presently incoming sun light is not transformed in its entirely, as much degradation occurs during photon absorption and electron transfer processes. A number of other innovative possibilities have also been researched. With respect to cost and efficiency one of the most promising devices is injection solar cells (ISC). By dint of the dye sensitised solar cell (DSSC) Grätzels findings provided the foundations for much research into this type of solar cell where the light absorbing molecule employed in is a dye.[1] The current is obtained through charge separation in the dye, which is initiated through the connection between the dye and a metal oxide on the one hand and a matched redox couple on the other. In a variant of the DSSC the charge separation processes can also occur between a nanoporous metal oxide and nanoparticles giving rise to a quantum dot sensitised solar cell (QDSSC).[2] The use of nanoparticle (NP) properties can be utilized for the harvesting of solar energy, as demonstrated by Kamat and coworkers[3] who were able to exploit these findings subsequently and prepare a number of nanoparticle based solar cells. Nanoparticle research has comprised a wide field of science and nanotechnology for a number of years. As the size of a material approaches dimensions on the nm scale the surface properties contribute proportionally more to the sum of the properties than the volume due to the increase in the surface to volume ratio. These dimensions also constitute a threshold in which quantum physical effects need to be taken into account. Hence the properties of devices or materials in this size regime are inevitably size dependent. The basic principles can be described by two different theories, one of which is based on molecular orbital theory in which the particle is treated as a molecule. For this reason n atomic orbitals with the same symmetry and energy can build up n molecular orbitals through their linear combination based on the LCAO method (Linear Combination of Atomic Orbitals).[4] In the case of solids the orbitals build up energy bands, where the unoccupied states form the quasi continous conduction band (CB) and the occuppied states form the quasi continous valence band (VB). The energy \"forbidden\" area in between these two bands is called the band gap. The band gap is a fixed material property for bulk solids but depends on size in the case of the nanoparticles. In contrast to the LCAO method, simplified solid state theory will be used throughout the present work, the theoretical background of which is provided by the effective mass approximation.[5] When an absorption of a photon occurs, an exciton (electron-hole pair) can be generated. By promoting an electron (e-) from the valence band into the conduction band a hole (h+) may be said to remain in the valence band. By comparison to bulk solids, in a small particle the free charges can sense the potential barrier i.e. the edges of the nanoparticle. Analogous to the particle in a box model this potential barrier interaction results in an increase in the band gap as the particle size decreases. In a solar cell NPs with a particle size which possess a band gap energy in the near infrared (NIR) may be utilised and therefore the NPs will be able to absorb in this spectral region. However NPs also have the ability to absorb higher energy photons due to the continuum present in their band structure, so that almost the entire sun spectral range from the NIR up to UV wavelengths may be absorbed just by using the appropriate NP material and size. Suitable NPs are metal chalcogenides e.g. MX (where M = cadmium, zinc or lead and X = sulfur, selenium or tellurium) because of their bandgap size[6–10] and their relative band positions compared to those of the semiconductor oxide states. Both the TiO2/CdSe[11–14] and TiO2/CdTe[15–18] systems have already been successfully fabricated and many of the anomalies reported.[3] Much interest in the lead chalcogenides has been generated by reports that they may feature the possibility to exhibit multiple exciton generation (MEG) where the absorption of one high energy photon can result in more than one electron-hole pairs.[19–25] Currently electrochemical impedance spectroscopy (EIS) is being used more and more to clarify processes at polarisable surfaces and materials such as nanoparticles. Likewise this method has been rediscovered in photovoltaic research and its use in the characterisation of DSSCs has been discussed in the literature.[26–31] In a number of publications the evaluation of nanoporous and porous structures has been quite extensively explored.[28,29,32–34] Since the mid-20th century Jaffé’s[35] theoretical work concerning the steady- state ac response of solid and liquid systems lead to the formation of the basics of EIS. Further developments in the measurement technology have lead to a broader range of analysis becoming possible. Nevertheless the most challenging part still remains the interpretation of the results and especially to merge the measured data with the theoretical model. EIS quantifies the changes in a small ac current response at electrode electrolyte interfaces i.e. the rate at which the polarized domain will respond, when an ac potential is applied. In this way dielectric properties of materials or composites, such as charge transfers, polarization effects, charge recombination and limitations can be measured as a function of frequency and mechanistic information may be unveiled. Hence EIS allows one to draw a conclusion concerning chemical reactions, surface properties as well as interactions between the electrodes and the electrolyte. Other very useful tools that may be employed for quantifying electron transfer processes and their time domains are intensity modulated photocurrent spectroscopy (IMPS) and intensity modulated photovoltage spectroscopy (IMVS). IMPS permits the generation of time-resolved plots of particular photo-processes in the system, each of which may be specifically addressed through varying the excitation wavelength. For the IMPS technique a sinusoidal wave with a small amplitude is applied, analogous to that of electrochemical impedance spectroscopy, but in this case the modulation is applied to a light source and not to the electrochemical cell as in EIS.[35] The current response is associated with the photogenerated charge carriers which flow through the system and finally discharge into the circuit. The amount of generated and discharged charge carriers is often different due to the presence of recombination and capture processes in surface or trap states. Ultimately the phase shift and magnitude of these currents reveal the kinetics of such processes. The only processes that will be addressed will be those that occur in the same frequency domain or on the same time scale as that of the modulated frequency of the illuminated light. In the literature some explanation of the kinetics of simple systems can be found and basic theories and introductive disquisitions may be found elsewhere.[36–38] Furthermore in solar cell research a multiplicity of studies are available which give an account of IMPS measurements on TiO2 nanoporous structures. Such studies permitted proof for the electron trapping and detrapping mechanism in TiO2 surface states.[39,40] An analysis of TiO2 electrodes combined with a dye sensitization step was established in the work of Peter and Ponomarev.[41–43] Hickey et.al.[44,45] have previously published kinetic studies on CdS nanoparticle (NP) modified electrodes. A theory was presented which allows for the IMPS data to be the interpreted in the case of CdS NP based electrodes. The back transfer, recombination and surface states have been demonstrated to be important as was determined from their inclusion in the theory. Similar attempts to explain the kinetics of CdS quantum dots are described by Bakkers et.al.[46]. In the present work the most important questions concern the behaviour of the photovoltaic assembly. Such assemblies can be equated with an electrode in contact with an electrolyte. Preliminary remarks about such electrodes as components of an electrochemical cell will be introduced in the first part of chapter 2. Thereafter the properties of electrodes in contact with the electrolyte and under illuminated conditions are illustrated. This is followed by a description of the important electrochemical and opto-electrochemical methods which have been employed in these studies. In particular, two separate subsections are dedicated to the methods of EIS and IMPS and the experimental section which are then linked to the theoretical section. The synthesis of all substances used and the preparation of the solar cell substrates are also dealt with in this section as will the equipment used and the instrument settings employed. The optical response of the working photoactive electrode is not only dependent on the substances used but also on their arrangement and linkage. The substrate which was employed in chapter 3 consists of a nanoporous ZnO gel layer upon which an organic linker has been placed in order to connect the oxide layer with the light absorbing component, the PbS NPs. Chapter 3 deals with the linker dependence on the ZnO layer and reports the typical optical characteristics and assembly arrangements of six different linkers on the ZnO layer which is an important intermediate stage in the fabrication of an ISC. The questions concerning how the type of linking affects the photo response and other electrochemical interactions of the complete solar cell substrate will be outlined in chapter 4. Further an examination of the electrochemical and opto-electrochemical behaviours of the samples will be presented similar to that presented in chapter 3. The most interesting substrate resulting from the investigations as described in chapter 3 and 4 will be used for a more in-depth characterisation by EIS in chapter 5. A suitable model and the results of the calculation of the ISC and the intermediate stages will be presented. The potential dependence, the dependence on the illuminated wavelength and also the size dependence of the PbS nanoparticles will be discussed. It will be revealed that ZnO is chemically unstable in contact with some of the linkers. For that reason the same linker study has been repeated with the more stable TiO2 employed as the wide band metal oxide. Comparisons between the different semiconductor metal oxides are made in chapter 6. In addition a number of open questions which previously had remained unanswered due to the instability of the ZnO can now be answered. In chapter 7 another highly porous structure different from that of the ZnO gel structure has been studied to determine its suitability as an ISC substrate. The structure arises from the electrodeposition of a ZnO reactant in the presence of eosin Y dye molecules. In the end the desorption of the dye provides a substrate with a high degree of porosity. Compared to the ZnO gel which was prepared and used for measurements in chapter 3 and 4, the electrodeposited ZnO is of a higher crystallinity and possesses a more preferential orientation. This results in a lower amount of grain boundaries which in turn results in fewer trap processes and subsequently yields a higher effective diffusion of the electron through the layer.[47,48] Optical and (opto-)electrochemical methods have been used for the basic characterisation of the untreated ZnO/Eosin Y and all other materials used in the fabrication of the ISC and a comparison with the ZnO gel used in chapter 3 and 4 will be made. Finally in chapter 8 an alternative metal oxide structure will be discussed. The background to this last chapter is to examine the influence of the ISC where the oxidic layer is present as a highly periodic arrangement, known as a photonic crystal. The TiO2 metal oxide which was also used in chapter 6 has been structured to form an inverse opal. First preparative findings and the first illustration of the (opto-)electrochemical results are presented. Consequently suggestions for improvements will be made. It is envisaged that the information gathered and presented here will help to achieve a deeper understanding of solar cells and help to improve the device efficiency and the interplay of the materials. Elementary understanding paves the way for further developments which can also contribute to providing devices for more efficient energy conversion.:Contents List of Abbreviations vii Legend of Symbols ix 1 Introduction and Motivation 1 2 Theoretical and Experimental Introduction 7 2.1 Basics of the (Opto-)Electrochemistry . . . . . . . . . . . . . . . . 7 2.1.1 Electrode-Electrolyte Interface Non-Illuminated . . . . . . 8 2.1.2 Electrode-Electrolyte Interface Under Illumination . . . . . 10 2.1.3 The Processes in the Injection Solar Cell (ISC) . . . . . . . 12 2.1.4 Cyclic Voltammetry (CV) . . . . . . . . . . . . . . . . . . 15 2.1.5 Chronoamperometry (CA) . . . . . . . . . . . . . . . . . . 16 2.1.6 Incident Photon to Current Conversion Efficiency (IPCE) . 16 2.1.7 Electrochemical Impedance Spectroscopy (EIS) . . . . . . 17 2.1.8 Intensity Modulated Photocurrent Spectroscopy (IMPS) . 21 2.2 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.2.1 Synthesis of ZnO Sol-Gel . . . . . . . . . . . . . . . . . . . 23 2.2.2 Synthesis of TiO2 Sol-Gel . . . . . . . . . . . . . . . . . . 24 2.2.3 Preparation of the ZnO/Eosin Y Substrate . . . . . . . . . 24 2.2.4 Syntheses and Preparation of the Inverse Opal . . . . . . . 25 2.2.5 The Syntheses for PbS Nanoparticle . . . . . . . . . . . . . 26 2.2.6 Preparation of the PbS Coated Substrates . . . . . . . . . 30 2.2.7 Preparation of the ISC . . . . . . . . . . . . . . . . . . . . 31 2.2.8 Material Characterisations and Instrument Settings . . . . 33 3 The Linker Attachment on a ITO/ZnO Substrate 37 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.2 The ITO/ZnO Film . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.2.1 The ZnO Layer and the ITO/ZnO Substrate Preparation . 40 3.2.2 The ZnO Structure as a Function of the Sintering Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.3 The Linker on the ITO/ZnO Film . . . . . . . . . . . . . . . . . . 48 3.3.1 The Linker Orientation on the ZnO layer . . . . . . . . . . 48 3.3.2 The Linker Interaction with the ZnO Gel . . . . . . . . . . 52 3.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4 The PbS Sensitized ITO/ZnO/linker Substrate 59 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 4.2 The ITO/ZnO/Linker/PbS Substrate . . . . . . . . . . . . . . . . 61 4.2.1 Spectroscopic Evidence for PbS on the ITO/ZnO/Linker Substrate . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 4.2.2 The Cyclic Voltammetry Study on the Substrates . . . . . 63 4.2.3 The Opto-Electrochemistry on the Substrates . . . . . . . 70 4.3 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 5 The EIS Study of the ITO/ZnO/MPA/PbS Substrate 75 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 5.2 The Substrate Assembly . . . . . . . . . . . . . . . . . . . . . . . 77 5.3 The Substrate Characteristics . . . . . . . . . . . . . . . . . . . . 78 5.4 The Model for the EIS Analysis . . . . . . . . . . . . . . . . . . . 83 5.5 The Results of EIS Data Fitting . . . . . . . . . . . . . . . . . . . 86 5.5.1 The EIS Results of the FTO/ZnO Substrate . . . . . . . . 86 5.5.2 The EIS Results of the FTO/ZnO/MPA Substrate . . . . 89 5.5.3 The EIS Results of the FTO/ZnO/MPA/PbS Substrate . . 92 5.5.4 The EIS Results for Shorter Illumination Wavelength . . . 96 5.5.5 The Resistance of the Linker . . . . . . . . . . . . . . . . . 111 5.6 General Remarks on the Modelling . . . . . . . . . . . . . . . . . 112 5.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 6 TiO2 based Injection solar Cell 119 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 6.2 The ITO/TiO2 Film . . . . . . . . . . . . . . . . . . . . . . . . . 121 6.3 The Linker and PbS Attachment on the ITO/TiO2 Substrate . . . 123 6.4 The Cyclic Voltammetry Study on the Substrates . . . . . . . . . 125 6.4.1 The Linker Sensitized ITO/TiO2 Film . . . . . . . . . . . 125 6.4.2 The ITO/TiO2/Linker/PbS Substrate . . . . . . . . . . . 126 6.5 The Opto-Electrochemistry on the Substrates . . . . . . . . . . . 127 6.6 Comparison Between ZnO and TiO2 Based ISCs . . . . . . . . . . 129 6.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 7 ZnO-Eosin Y based Injection Solar Cell 135 7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 7.2 The FTO/ZnO-Ey Film . . . . . . . . . . . . . . . . . . . . . . . 137 7.3 The PbS Attachment to the FTO/ZnO-Ey Film . . . . . . . . . . 137 7.4 The Cyclic Voltammetry Study on the Substrates . . . . . . . . . 140 7.5 The Opto-Electrochemistry on the Substrates . . . . . . . . . . . 142 7.5.1 The Linear Sweep Voltammetry (LSV) Study on the Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 7.5.2 The IPCE Measurements on the Substrates . . . . . . . . 144 7.5.3 The Photo Transient Measurements on the Substrates . . . 145 7.6 Comparison between ZnO and ZnO-Ey based ISC . . . . . . . . . 146 7.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 8 Injection Solar Cell meets Photonic Crystal 151 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 8.2 The Opal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 8.3 The Inverse Opal . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 8.4 The Inverse Opal based ISC . . . . . . . . . . . . . . . . . . . . . 159 8.4.1 The Substrate Characteristics . . . . . . . . . . . . . . . . 159 8.4.2 The Cyclic Voltammetry . . . . . . . . . . . . . . . . . . . 160 8.4.3 The Opto-Electrochemistry . . . . . . . . . . . . . . . . . 161 8.4.4 The EIS Measurements . . . . . . . . . . . . . . . . . . . . 163 8.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 9 Overall Conclusion 167 10 Outlook 173 Bibliography I A Acknowledgement XXV B Erklärung XXVII

碩士
國立清華大學
材料科學工程學系
101
The highest efficiency Cu(In,Ga)Se2(CIGS) thin film solar cells have reached 20%. However, the indium and gallium are rare elements in the crust. A promising quaternary semiconductor Cu2ZnSnS4(CZTS) has been proposed to replace CIGS. CZTS is composed of four earth abundant elements, and has some advantages such as high absorption coefficient, direct band gap of 1.5eV, and nontoxic material. The highest CZTS device was fabricated by the solution based hydrazine process. However, hydrazine is a vary toxic and unstable compound, so we choose the hot injection method to synthesize CZTS nanoparticles. We have successfully synthesized high quality CZTS nanoparticles by the hot injection method, and we discussed the CZTS growth mechanism via tuning reaction conditions. We used TEM to observe the size of different nanoparticles, and explained its nucleation and growth mechanism by LaMer model. We also measured CZTS by using XRD and Raman spectrum to identify its structures and phases, and we found that different crystallinity in different reaction condition. Different from other hot injection methods, we used slow injection synthesis to get the high quality CZTS, and we proposed a possible reason to explain why the CZTS nanoparticles possessed different cystallinity. Ostwald ripening and oriented attachment are two mechanisms which may result in different crystallinity during the growth. Moreover, we also observed wurtzite and kesterite CZTS would coexist in the hot injection synthesis.

碩士
國立臺灣大學
地質科學研究所
104
Graphite Encapsulated Metal (GEM) nanoparticles are spherical core-shell structured composite material with a diameter ranging from 5–100 nm. The core of GEM is metal, and its outer shell is composed of several layers of graphite/graphene which can preserve the inner core in a severe environment, such as from acid erosion and oxidation. It is well known that many different functional groups, including carboxyl and hydroxyl, can be easily attached to the surface of carbon materials. Recently, several studies have revealed that GEM has a great potential to become a novel material including, for example, in hydrogen storage and biomedical materials due to its unique properties. For instance, Wu et al.(2007) used polyethylene glycol and folic acid grafted on Fe-GEM for the heat treatment of cancer, and Chung et al. (2009) used Co-GEM as an electrochemical hydrogenation material. The modified tungsten arc-discharge method was developed by Teng et al. and Dravid et al. in 1995. This is the most practical method for producing a large quantity of GEM because it reduces the amount of carbon debris origin compared to the Krätschmer–Huffman method. However, the encapsulation efficiency of GEM remains low. Until 2012, with the help of the two-step mechanism model, we used n-propanol as the liquid carbon source to synthesize GEM, significantly increasing its encapsulation efficiency from 20–30 wt% to around 80 wt%, and presenting a preliminary method for controlling the particle size of GEM through different liquid carbon sources. However, we faced two difficult issues after switching the carbon source from solid to liquid. First, this method could disturb the arc discharge which causes the discontinuity of the experiment, leading to the lockout unsustainable injection. Second, the consumption rate of the tungsten rod rose from 1 mm/h to 420 mm/h, making it difficult to synthesize large quantities of well-encapsulated GEM. In addition, the detailed mechanism, after entering the liquid carbon source, still remains unclear. The purposes of this study are to realize the changes of arc in the cabin and to resolve problems after using the liquid carbon source. In order to solve the problems, this research has installed a liquid metering pump to regulate the amount and direction of each injection, so that the carbon source can be directed to mainly spray the synthetic region of GEM, which is called the coalescence region. This method avoids the resistance caused by dripping liquid along the tungsten rod, and successfully sustained the experiment. The TEM images show that the synthesized GEMs, using a liquid metering pump, retain a complete core-shell structure, and the utilization of carbon source calculated by TGA data shows significant improvement, from 20% to 64%. Furthermore, we listed the possible reasons causing the high consumption rate of tungsten rod, and verified them by theoretical calculation and manner of experiments, one by one. It can be speculated by OES data that the dominant gas in the center of the arc changed from helium to hydrogen. In the meantime, the arc temperature rose show by the color changing into blue and white, representing the higher arc temperature is the main reason causing the tungsten melting rate to increase 420-fold. After calculating the heat conduction, we confirmed that increasing the diameter of the tungsten rod can immediately solve this problem. Since it is feasible to control the injection rate through the use of a liquid metering pump, we tried to figure out the encapsulation efficiency of GEM over time when synthesizing GEM. Under the same experimental parameters and total liquid injection volume, we compared the results of two different injection rates, 10μL/min and 100μL/min, and found that using the former injection rate can result in 5-fold higher encapsulation efficiency. According to the two-step mechanism of GEM, we speculated that adding liquid carbon source during arc discharge would rapidly increase the carbon proportionate of the coalescence region; however, the carbon vapor will quickly leave the coalescence region via convection. Thus, for the same total liquid injection volume, taking a small amount and injecting it a few times is the best way to inject the liquid carbon source; it can significantly improve the encapsulation efficiency and the utilization rate of the carbon source. 　　Lastly, based on the experiment results, we proposed a model that can explain the transformation of the arc body from bell-shaped to columnar, after injecting the liquid carbon sources. Furthermore, our model raises the potential of employing GEM to fundamental science and applied material fields.

碩士
國立臺灣科技大學
化學工程系
103
This study is comprised of two parts: the first part focused on the synthesis of the complexes of Ag@carbon nanotubes (Ag@CNTs) and preparation of horseradish peroxidase (HRP) biosensor. Carbon nanotubes (CNTs) have drawn considerable attention in recent years because of their superior properties that include the larger specific surface area and more electrocatalytic activity, which can significantly enhance the amperometric anodic signal. In this study, the incorporation of Ag nanoparticles on CNTs aimed to enhance the electrical conductivity and reduce the contact resistance. Moreover, various analytical tools were employed to verify the physical-chemical and morphology characteristics of the prepared Ag@CNTs. An amperometric biosensor base on HRP and chitosan- Ag@carbon nanotubes (Ch-Ag@CNTs) on screen printed carbon electrode (SPE). The current responses were detected by phenolic compound at applied voltage -50 mV. The results showed that two sensitivity of phenol detection were 2.37 μA/μM cm2 (0.75 - 100 μM, R2:0.976) and 0.749 μA/μM cm2 (100 - 400 μM, R2:0.979) and limitation of detection was 0.375 μM. It retained 80% of its initial current response after 30 days. For the second part, a custom-made flow channel was applied which mainly plays the role of minimize the required components for reactions and further facilitated the integration, automation, and parallelization for the designated biochemical processes. In addition, the prepared Ch-Ag@CNTs in the first part and HRP were incorporated on SPE for the detection of phenol, which was further combined with a custom-made flow channel, to form “Flow Injection Analysis” (FIA). The FIA designed in this study allows the manipulation of small fluid volume, from micro- down to pico- liter, with exceptional accuracy. In summary, the proposed FIA would have the advantages including low price, rapid response time, high accuracy, and smaller reaction volume that can reduce the thickness of the diffusion layer and effectively convey electronic signals between solid-liquid phases when compared with the conventional system, and could be utilized for a wider range of applications. The results showed that the sensitivity of phenol detection were 2.77 μA/μM cm2 (0.5 - 20 μM, R2:0.974).

Cette thèse présente les travaux de développement de formulations injectables capables de se solidifier in situ, formant ainsi un implant piégeant des microparticules magnétiques en vue du traitement de tumeurs par induction magnétique d'une hyperthermie locale modérée. Nous exposons tout d'abord le contexte physique, biologique et clinique de l'hyperthermie comme traitement anticancéreux, particulièrement des modalités électromagnétiques. Les performances in vitro et in vivo des matériaux et formulations sont alors présentées. L'objet du chapitre suivant est la caractérisation des propriétés physicochimiques, magnétiques, et chauffantes, dans un champ magnétique alternatif (115 kHz, 9 - 12 mT), des microparticules de silice renfermant des nanoparticules d'oxyde de fer superparamagnétiques (SPIONs) et de deux de leurs formulations: un hydrogel d'alginate de sodium et un organogel de poly(éthylène-co-alcool vinylique) dans le diméthylsulfoxide. Finalement, nous présentons le potentiel thérapeutique de 20 minutes d'hyperthermie locale induite après injection de l'organogel superparamagnétique dans un modèle murin sous-cutané de tumeurs nécrosantes de colocarcinome humain.