Self-assembly of nanorods (NRs) enhanced by functionalization with liquid crystals (LC) ligands has been demonstrated. First, CTAB (cetyltrimethylammonium bromide) coated gold NRs were prepared in water through a modified one-step seed growth process. The hydrophilic GNRs were then converted into hydrophobic NRs employing a surface modification process using liquid crystalline organosilanes. The functionalized GNRs were characterized by TEM (transmission electron microscopy) and SAXS (small angle X-ray scattering) to investigate the packing mode of the GNRs. The results propose models of the assembly of the GNRs depending on nature and connectivity of the attached liquid crystal molecules. Furthermore, a macroscopic orientation of the GNRs doped in LC was achieved via an alignment technique of the liquid crystal host. SAXS analysis of the doped DLC indicated modification of lattice parameters due to the insertion of the DLC-GNRs, which resulted in an enhancement of the charge carrier mobility.

This thesis reported synthesis of TiO2 nanostructures and Fe2O3 nanostructures and studied on self-assembling process. The morphologies, compositions, and physicochemical properties of the prepared samples were characterized by TEM, FESEM, XRD, FTIR, UV, and SQUID etc. Nanoparticles of transition metal oxides own their special function to become an interesting hot research topic in the recent decades. In particular, superparamagnetic iron oxide nanoparticles can be used as drug delivery agent and new hard disc drive materials. They have wide application in environment industry as well. Titanium dioxide nanoparticles can be applied in photocatalysts, UV protectors and dye sensitive solar cell etc. Their wide industrial applications for advanced technology development motivate scientists to develop simple, economical and novel synthetic methods, and explore their applications, so that the commercialization of the production of the nanomaterials becomes feasible. The objective of this project is to develop an effective, simple and economical technical route for synthesis of nanosized iron oxide and titanium oxide particles/rods/films. The approach and the progress are outlined as follows. Based on extensive literature reading on the project related area, a novel self-assembling technical route for iron oxide nanostructure and architecture was proposed which has been confirmed to be effective. Detailed experimental investigation on the synthesis of nanoparticles/rods, and instrumental characterization of the particle size, structure, and crystallites, etc. via TEM, FESEM, XRD, FTIR, UV, SQUID are conducted. Uniform nanorods of hematite iron oxide and titanium oxide nanospheres, and anatase TiO2 thin film with micropores have been successfully achieved. Some preliminary exploration for applications of the synthesized nanomaterials has also been carried out. Firstly, a novel assembled scheme of iron oxide nanostructure and architecture by selfassembling process was investigated. The sol-gel technical route was employed to synthesize nearly uniform nanorods of hematite particles. Morphologies and physicochemical properties of iron oxide nanostructure were characterized by analytical instrument. Secondly, titanium oxide nanospheres were synthesized via a hydrothermal process using titanium isopropoxide as the precursor. Titanium oxide nanospheres with inner nanospace andhighly organized crystallites in the shell structure and surface regions were synthesized. It demonstrated that the technical route developed in this work has a high versatility for structural engineering of various targeted morphological products. Thirdly, a simple process of preparing anatase TiO2 thin film with micropores was pursued. The synthesized nano thin film with micropores was used for the material of dye-sensitive solar cell; and effective electron transfer of titanium oxide electrode was confirmed by electrochemical voltammetry. Preparation of the titanium oxide electrode and its electrochemical analysis was studied. The application of the titanium oxide of microporous thin film material as a promoter for electrochemistry voltammetry measuring system was explored in this thesis. In conclusion, the iron oxide nanorods with superparamagnetic property were successfully synthesized by a simple method with low cost materials. Titanium oxide hollow nanospheres were achieved by the assistance of copolymer template. Titanium oxide thin film with microporous structure with significantly high efficiency in electron transfer was realized. Further researches on the synthesis of hybrid iron oxide and titanium oxide nanoparticles, their crystal growth architecture and mechanism, as well as exploration of their applications are recommended.

The objectives of this thesis were to optimize the synthesis and surface coating of metallic and semiconductor nanoparticles, to understand how these materials interact with cells and physiological systems and to investigate how they can be used to deliver thermal therapy for medical applications. Reproducible high-yield synthesis of gold nanorods and surface coating with a variety of polymers and silica was optimized. Using gold nanorods as a model system, the relationship between particle surface chemistry, surface charge and cellular uptake was studied, as well as the toxicity of nanoparticles of different surface chemistry. Low toxicity in vitro was encouraging and was confirmed in vivo by intravenously injecting Sprague-Dawley rats with semiconductor quantum dots of various surface coatings. Low toxicity was found during biochemical, haematological and pathological assessment, and these results indicate that applications of nanoparticles should be further investigated. One such application is the use of near infrared absorbing gold nanorods in remotely activated hyperthermia. It was shown that gold nanorods act synergistically with the chemotherapeutic cisplatin to improve cytotoxicity, and reduce the required cytotoxic drug dose to 33% of the unheated amount. Due to the success of hyperthermia treatment in vitro, continuing and future work involves the use of gold nanorods ex vivo on excised human corneas in a novel application to weld corneal tissue for improved wound closure following cataract surgery.

Ao longo dos últimos anos tem aumentado o interesse da comunidade científica no desenvolvimento de estruturas de borato de magnésio. Geralmente, o borato de magnésio é utilizado em conjunto com outros materiais como metais, polímeros, cerâmicas ou macromoléculas formando compósitos. Este borato tem sido largamente utilizado para reduzir o coeficiente de fricção e aprimorar as propriedades mecânicas de compósitos, atuando como material anti-desgaste e inibidos de corrosão. Dentre as fases de borato de magnésio, o Mg2B2O5 se destaca por apresentar potencial para aplicações tais como catalisador para conversão de hidrocarbonetos, agente para tratamento eletrocondutivo, semicondutor e material luminescente para aplicação em tubos de raios catódicos. Acredita-se que ao reduzir as dimensões do bulk de borato de magnésio a dimensões nanométricas, pode-se oferecer excelentes características para desenvolver e melhorar as potenciais aplicações acima mencionadas. Em geral, estruturas em nanoescala como tubos, fios, rods, cintos e whiskers têm sido o foco de intensiva pesquisa. Buscando a compreensão dos mecanismos para produção de nanoestruturas de boratos de magnésio, este trabalho está focado no desenvolvimento de uma rota de síntese de nanorods de Mg2B2O5 que permita a produção de um material com elevada pureza e homegeneidade estrutural a fim de possibilitar uma futura aplicação em dispositivos nanotecnológicos. Os nanorods foram sintetizados utilizando como precursor B2O3 e Mg metálico em um reator de CVD. Foi analisado o emprego de diferentes atmosferas para a reação, partindo de H2, Ar e acetonitrila (CH3CN). Foi estudado também a influência da temperatura na morfologia e composição dos nanorods. As propriedades físico-químicas das estruturas desenvolvidas foram caracterizadas por FTIR e DRX. A estrutura morfológica foi analisada por MEV e MET e as propriedades óticas por DRS. De acordo com os resultados, os nanorods foram obtidos com alto grau de pureza e homogeneidade morfológica utilizando uma atmosfera redutora composta por H2 e CH3CN. / Over the last few years the interest of the scientific community has increased in the development of magnesium borate structures. Borato has been widely used to reduce the coefficient of friction and improve the mechanical properties of composite materials such as anti-wear and corrosion. Generally, the magnesium borate is used together with other materials such as metals, polymers, ceramics and macromolecules to form compounds. Among the borate magnesium phases, Mg2B2O5 contrasts for presenting potential for applications such as acting as a catalyst for hydrocarbon conversion, as an agent for electroconductive treatment, as a semiconductor and luminescent material for application in cathode ray tubes. It is believed that by reducing the borate magnesium bulk dimensions to dimensions of nanostructures, it can provide excellent characteristics to develop and improve the potential applications mentioned above. In general, nanoscale structures such as tubes, wires, rods, belts and whiskers have been the focus of intensive research. Seeking to understand the mechanisms for production of magnesium borate nanostructures, this work is focused on the development of a synthesis method for Mg2B2O5 nanorods, enabling the production of a material with high purity and structural homogeneity to enable future application in nanotechnological devices. The physicochemical properties of the structures developed were characterized by FTIR and XRD. The morphological structure was examined by SEM and TEM and the optical properties by DRS. According to the results, high purity and morphological uniform nanorods were obtained using a H2 and CH3CN reducing atmosphere.

Ao longo dos últimos anos tem aumentado o interesse da comunidade científica no desenvolvimento de estruturas de borato de magnésio. Geralmente, o borato de magnésio é utilizado em conjunto com outros materiais como metais, polímeros, cerâmicas ou macromoléculas formando compósitos. Este borato tem sido largamente utilizado para reduzir o coeficiente de fricção e aprimorar as propriedades mecânicas de compósitos, atuando como material anti-desgaste e inibidos de corrosão. Dentre as fases de borato de magnésio, o Mg2B2O5 se destaca por apresentar potencial para aplicações tais como catalisador para conversão de hidrocarbonetos, agente para tratamento eletrocondutivo, semicondutor e material luminescente para aplicação em tubos de raios catódicos. Acredita-se que ao reduzir as dimensões do bulk de borato de magnésio a dimensões nanométricas, pode-se oferecer excelentes características para desenvolver e melhorar as potenciais aplicações acima mencionadas. Em geral, estruturas em nanoescala como tubos, fios, rods, cintos e whiskers têm sido o foco de intensiva pesquisa. Buscando a compreensão dos mecanismos para produção de nanoestruturas de boratos de magnésio, este trabalho está focado no desenvolvimento de uma rota de síntese de nanorods de Mg2B2O5 que permita a produção de um material com elevada pureza e homegeneidade estrutural a fim de possibilitar uma futura aplicação em dispositivos nanotecnológicos. Os nanorods foram sintetizados utilizando como precursor B2O3 e Mg metálico em um reator de CVD. Foi analisado o emprego de diferentes atmosferas para a reação, partindo de H2, Ar e acetonitrila (CH3CN). Foi estudado também a influência da temperatura na morfologia e composição dos nanorods. As propriedades físico-químicas das estruturas desenvolvidas foram caracterizadas por FTIR e DRX. A estrutura morfológica foi analisada por MEV e MET e as propriedades óticas por DRS. De acordo com os resultados, os nanorods foram obtidos com alto grau de pureza e homogeneidade morfológica utilizando uma atmosfera redutora composta por H2 e CH3CN. / Over the last few years the interest of the scientific community has increased in the development of magnesium borate structures. Borato has been widely used to reduce the coefficient of friction and improve the mechanical properties of composite materials such as anti-wear and corrosion. Generally, the magnesium borate is used together with other materials such as metals, polymers, ceramics and macromolecules to form compounds. Among the borate magnesium phases, Mg2B2O5 contrasts for presenting potential for applications such as acting as a catalyst for hydrocarbon conversion, as an agent for electroconductive treatment, as a semiconductor and luminescent material for application in cathode ray tubes. It is believed that by reducing the borate magnesium bulk dimensions to dimensions of nanostructures, it can provide excellent characteristics to develop and improve the potential applications mentioned above. In general, nanoscale structures such as tubes, wires, rods, belts and whiskers have been the focus of intensive research. Seeking to understand the mechanisms for production of magnesium borate nanostructures, this work is focused on the development of a synthesis method for Mg2B2O5 nanorods, enabling the production of a material with high purity and structural homogeneity to enable future application in nanotechnological devices. The physicochemical properties of the structures developed were characterized by FTIR and XRD. The morphological structure was examined by SEM and TEM and the optical properties by DRS. According to the results, high purity and morphological uniform nanorods were obtained using a H2 and CH3CN reducing atmosphere.

Ao longo dos últimos anos tem aumentado o interesse da comunidade científica no desenvolvimento de estruturas de borato de magnésio. Geralmente, o borato de magnésio é utilizado em conjunto com outros materiais como metais, polímeros, cerâmicas ou macromoléculas formando compósitos. Este borato tem sido largamente utilizado para reduzir o coeficiente de fricção e aprimorar as propriedades mecânicas de compósitos, atuando como material anti-desgaste e inibidos de corrosão. Dentre as fases de borato de magnésio, o Mg2B2O5 se destaca por apresentar potencial para aplicações tais como catalisador para conversão de hidrocarbonetos, agente para tratamento eletrocondutivo, semicondutor e material luminescente para aplicação em tubos de raios catódicos. Acredita-se que ao reduzir as dimensões do bulk de borato de magnésio a dimensões nanométricas, pode-se oferecer excelentes características para desenvolver e melhorar as potenciais aplicações acima mencionadas. Em geral, estruturas em nanoescala como tubos, fios, rods, cintos e whiskers têm sido o foco de intensiva pesquisa. Buscando a compreensão dos mecanismos para produção de nanoestruturas de boratos de magnésio, este trabalho está focado no desenvolvimento de uma rota de síntese de nanorods de Mg2B2O5 que permita a produção de um material com elevada pureza e homegeneidade estrutural a fim de possibilitar uma futura aplicação em dispositivos nanotecnológicos. Os nanorods foram sintetizados utilizando como precursor B2O3 e Mg metálico em um reator de CVD. Foi analisado o emprego de diferentes atmosferas para a reação, partindo de H2, Ar e acetonitrila (CH3CN). Foi estudado também a influência da temperatura na morfologia e composição dos nanorods. As propriedades físico-químicas das estruturas desenvolvidas foram caracterizadas por FTIR e DRX. A estrutura morfológica foi analisada por MEV e MET e as propriedades óticas por DRS. De acordo com os resultados, os nanorods foram obtidos com alto grau de pureza e homogeneidade morfológica utilizando uma atmosfera redutora composta por H2 e CH3CN. / Over the last few years the interest of the scientific community has increased in the development of magnesium borate structures. Borato has been widely used to reduce the coefficient of friction and improve the mechanical properties of composite materials such as anti-wear and corrosion. Generally, the magnesium borate is used together with other materials such as metals, polymers, ceramics and macromolecules to form compounds. Among the borate magnesium phases, Mg2B2O5 contrasts for presenting potential for applications such as acting as a catalyst for hydrocarbon conversion, as an agent for electroconductive treatment, as a semiconductor and luminescent material for application in cathode ray tubes. It is believed that by reducing the borate magnesium bulk dimensions to dimensions of nanostructures, it can provide excellent characteristics to develop and improve the potential applications mentioned above. In general, nanoscale structures such as tubes, wires, rods, belts and whiskers have been the focus of intensive research. Seeking to understand the mechanisms for production of magnesium borate nanostructures, this work is focused on the development of a synthesis method for Mg2B2O5 nanorods, enabling the production of a material with high purity and structural homogeneity to enable future application in nanotechnological devices. The physicochemical properties of the structures developed were characterized by FTIR and XRD. The morphological structure was examined by SEM and TEM and the optical properties by DRS. According to the results, high purity and morphological uniform nanorods were obtained using a H2 and CH3CN reducing atmosphere.

Nano structured wide band gap semiconductors have attracted attention of many researchers due to their potential electronic and optoelectronic applications. In this thesis, we report successful synthesis of well aligned Eu doped ZnO nano-rods prepared, for the first time to our knowledge, by pulsed laser deposition (PLD) without any catalyst. X-ray diffraction (XRD) patterns shows that these Eu doped ZnO nanorods are grown along the c-axis of ZnO wurtzite structure. We have studied the effect of the PLD growth conditions on forming vertically aligned Eu doped ZnO nanorods. The structural properties of the material are investigated using a -scanning electron microscope (SEM). The PLD parameters must be carefully controlled in order to obtain c-axis oriented ZnO nanorods on sapphire substrates, without the use of any catalyst. The experiments conducted in order to identify the optimal growth conditions confirmed that, by adjusting the target-substrate distance, substrate temperature, laser energy and deposition duration, the nanorod size could be successfully controlled. Most importantly, the results indicated that the photoluminescence (PL) properties reflect the quality of the ZnO nanorods. These parameters can change the material’s structure from one-dimensional to two-dimensional however the laser energy and frequency affect the size and the height of the nanorods; the xygen pressure changes the density of the nanorods.

Zinc oxide (ZnO) semiconductors have been utilized by many researchers, due to its unique properties beneficial for functional devices. In particular, gadolinium (Gd)–doped ZnO exhibits high ferromagnetic and electrical properties, which is attributed to defect/impurity bands mediated by Gd dopants. In this dissertation, I study the effects of Gd concentration, oxygen pressure using pulsed laser deposition (PLD), and thermal annealing on the optical and structural properties of undoped and Gd-doped ZnO films and nanostructures. Moreover, as the growth of practical ZnO nanostructures-based devices without catalyst, while presently challenging, is highly important for many applications. Thus, for the first time, a novel method is developed for growing well aligned ZnO nanorods (NRs) by optimizing PLD conditions using Gd-doped ZnO target without any catalyst in a single step. This study shows that, both the lattice orientation of the substrate and the Gd characteristics are significant in enhancing the NR growth. Our findings reveal that precise control of the NR density can be achieved by changing the oxygen partial pressure. Furthermore, due to the Gd incorporation, these NRs possess favorable electrical properties with a significant mobility of 177 cm2 (V.s)-1 compared to that reported in literature. Nonetheless significant challenges need to be overcome to achieve reproducible and stable p-type ZnO for commercial applications. Hence, several attempts based on n-type ZnO grown on foreign p-type substrates were made to achieve high-performance devices and overcome the issues arising when p-type doped ZnO is employed. Moreover, Growth of ZnO nanostructures on a foreign p-type substrates does not require a lattice-matched p-type substrate. Thus, for the first time, PLD conditions are improved to grow high quality ZnO nanotubes (NTs) with high optical, structural and electrical properties on a p-type Si (100) substrate without catalyst for high-performance devices. A fabrication of high performance UV photodetector (PD) based on ZnO NT/p-Si is demonstrated with superior responsivity (up to ~ 101.2 AW-1) compared to that reported in literature. This new and simple method demonstrates that the PLD system has a significant potential for improving the performance of materials used in a wide range of electronic and optoelectronic applications.

Diabetes mellitus is a potentially lethal disease that affects 7.6 percent of American people. In the US, it is recognized as the 6th leading cause of death. Failure to control blood glucose levels (BGL) in patients with either type of diabetes can lead to other serious complications as well, such as loss of limb, blindness and other health problems. Controlling and monitoring the BGL in post-op and intensive care patients in the hospital is also vital to their health. Currently the most reliable method of monitoring BGL is through an invasive procedure which monitors the amount of glucose in blood directly. A non-invasive glucose sensor would drastically improve the treatment of sensitive patients, and serve to improve the quality of diabetic patients' lives. This glucose sensor is strongly based upon the mercury sensor developed by F.E. Hernandez and his colleagues. Glucose is used as a reducing agent to reduce mercury from Hg2+ to Hg0, which will form amalgams with the gold nanorods in solution. The change in aspect ratio of gold nanorods leads to a change in the UV-Visible spectrum of the solution. The blue shift seen was measured and correlated with the glucose concentration of the system. The system was then tested varying conditions such as pH, temperature, gold nanorod concentration, and mercury concentration. A preliminary study of the kinetics of the reaction was also done. The results showed a limit of detection of 1.58x10-13 and a linear dynamic range covering the concentrations of human tear glucose levels that are currently cited in the literature.

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