Thesis (DTech (Chemistry))--Cape Peninsula University of Technology, 2015. / Researchers around the world are now focusing on inculcating green chemistry principles in all level of research especially in nanotechnology to make these processes environmental friendly. Nanoparticles synthesized using green chemistry principles has several advantages such as simplicity, cost effectiveness, compatibility for biomedical and pharmaceutical applications and large scale production for commercial purpose. Based on this background, this thesis present the design, synthesis, characterization and applications of various CdSe based core-shell and core-multi shell quantum dots (QDs), quantum dots-polymer nanocomposites, silver nanoparticles (Ag-NPs) and silver nanocomposites via completely green methods. Various QDs like CdSe/CdS/ZnS and CdSe/ZnS, and there polymer nanocomposites were successfully synthesized and characterized. The high quality of the as-synthesized nanoparticles was confirmed using absorption and photoluminescence (PL) spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM) and high resolution TEM (HRTEM). Detailed optical and morphological characterization showed that the CdSe/CdS/ZnS core-multi shell QDs were small, monodispersed with high fluorescent intensity and narrow emission width. The CdSe/CdS/ZnS core multi-shell QDs were dispersed in epoxy polymer matrix to obtain fluorescent epoxy nanocomposite. The brillouin spectroscopy analysis revealed that the presence of QDs inside polymer composite reduces the acoustic frequency of the polymer. Highly fluorescent CdSe/ZnS core-shell QDs was also synthesized and dispersed in PMMA polymer matrix to prepare bright yellow emitting nanocomposite film. The as-synthesized QDs also undergone surface exchange to convert the organically soluble nanomaterial to water soluble. After the ligand exchange, the morphology and above all the fluorescence property of the quantum dots remained intact. In another approach, HDA-capped CdSe nanoparticles were synthesized in the absence of an inert gas followed by dispersion in polymer polycaprolactone to produce orange light emitting electrospun polymer nanocomposite nanofibre.

Ph.D., Faculty of Science, University of the Witwatersrand, 2011 / ABSTRACT Page | iiAbstract i The deposition of carbon during catalytic reactions has a long history, with major efforts initially focused towards their prevention rather than synthesis. However the discovery of fullerenes and later that of carbon nanotubes by Iijima, shifted scientific focus towards the synthesis, characterization and application of carbon deposits. This renewed interest in carbon based materials, has revealed a universe of extraordinarily shaped carbon materials (SCMs) in the nano and micro range, from tubes and helices to horns and most recently graphene. It has been noted that there exists a relationship between the morphology of the carbon material and its inherent properties, making them highly prized for numerous technological applications. However before these carbon materials can be effectively exploited control over their selective synthesis is necessary, a problem that has been solved with only limited success. As such, there still exists a need to develop synthetic strategies that would yield shaped carbon materials selectively. More importantly, it is essential that a better understanding of the growth factors that lead to differently SCMs is obtained. In this study we have highlighted the parametric conditions for optimum growth of carbon helices, as well as that of carbon fibers with unique structure. We have found that catalyst morphology and the carbon source are key aspects, which control carbon material growth and morphology. The synthesis of carbon materials using bi and tri-metallic supported catalyst systems revealed that Cu was an effective promoter for obtaining helices, particularly at low temperatures (≤ 550 ˚C). On further investigation, Cu was shown to exhibit incredible carbon deposition capabilities at temperatures as low as 200 ˚C. Adjustments of the catalyst preparation conditions (support, metal counter ion, solvent and reduction temperature) and synthesis temperature, revealed that the yield and morphology of the carbon deposit could be altered to selectively produce both straight and helical carbon fibers. A TEM tomography study revealed that the copper particles that gave distorted decahedra formed helical fibers, while trigonal bi-pyramidal particles gave linear fibers. Various plate-like particles revealed that as the number of sides of a catalyst particle varied (3, 4, 5 or 6) there was a corresponding change in the Abstract Page | iv carbon fiber helicity. A relationship between catalyst particle morphology and fiber morphology was thus established. TEM analysis also revealed that catalyst particles underwent rapid reconstruction during carbon fiber synthesis, and that the carbon source (gas environment) was influential in this reconstruction event. A NiOx (unsupported) catalyst was prepared and reactions with various substituted alkyne hydrocarbons were undertaken. Analysis revealed that different alkynes produced carbon fibers with varying morphologies. Using different alkynes in a sequential manner led to the formation of ‘co-block’ carbon fibers with an A-B-A-B... or A-B-C... morphology. Using different alkynes followed by acetylene led to the selective synthesis of straight, Y-junction or irregular carbon fibers. Accompanying these results was the observation that in each case the catalyst particle morphology was unique. Reaction of NiOx with trichloroethylene, in which trichloroethylene acted as a source of carbon for fiber growth, also restructured the Ni catalyst into a tetrahedral shape that gave tripod-like carbon growth. It was found that, substituted alkynes (and alkenes) provided a means for controlling catalyst particle morphology and hence carbon fiber morphology. The study has highlighted the relationship that exists between catalyst and SCM morphology, as well as the effect of hydrocarbons, not only as a source of carbon for SCM growth but also as a means of controlling catalyst morphology and SCM structures.

Thesis advisor: Michael J. Naughton / Thesis advisor: Michael J. Burns / Recent progress in the study of the brain has been greatly facilitated by the development of new measurement tools capable of minimally-invasive, robust coupling to neuronal assemblies. Two prominent examples are the microelectrode array, which enables electrical signals from large numbers of neurons to be detected and spatiotemporally correlated, and optogenetics, which enables the electrical activity of cells to be controlled with light. In the former case, high spatial density is desirable but, as electrode arrays evolve toward higher density and thus smaller pitch, electrical crosstalk increases. In the latter, finer control over light input is desirable, to enable improved studies of neuroelectronic pathways emanating from specific cell stimulation. Herein, we introduce a coaxial electrode architecture that is uniquely suited to address these issues, as it can simultaneously be utilized as an optical waveguide and a shielded electrode in dense arrays. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.

Photodynamic Therapy (PDT) has proven itself in previous studies to be a successful therapeutic treatment for surface tumors, but its effectiveness is limited to only shallow depths that allow for the penetration of light. This study demonstrates that we have improved upon the conventional method of PDT and have overcome the previous depth limitation by creating the light at the location of the tumor in situ. We conjugated a bioluminescent protein, Luciferase, to a semiconductor nanoparticle, TiO2, and with a cell specific antibody, anti-EGFR monoclonal antibody C225. The nanoconjugate, TiDoL-C225, was then activated by ATP and Luciferin in a reaction that creates reactive oxygen species (ROS) and induces apoptosis in the tumor cells. We created the optimal nanoconjugate synthesis protocol to make TiDoL and TiDoL-C225 for use in the PDT treatment. The TiDoL-C225 nanoconjugate is able to bind specifically to colon caner cells as the C225 antibody recognizes EGFR expressed at the surface of the cells, and further, when activated it will react only with the tumor cells. The optimal cell staining protocols were developed to visualize the treatment process and later analyze with the laser confocal microscope. The TiDoL nanoconjugate was found to only be operational and effective at killing tumor cells after being activated by Luciferin and ATP, which then enhances the control we have over the therapy. The TiDoL-C225 nanoconjugate increases the efficacy of binding to tumor cells and the speed of the reaction in the cells to begin apoptosis, even in lower concentrations when compared to the free TiDoL nanoconjugate. Finally, our PDT technique allowed us to monitor the tumor cells as they begin to undergo apoptosis in less than five minutes after the Luciferin was added to activate the reaction. The advantage of our method of PDT with the TiDoL-C225 nanoconjugate is that it can be used for early detection as well as developed into an effective treatment for cancers in all depths of tissue.

Metal oxide materials could offer earth-abundant, non-toxic alternatives to existing lightabsorber materials in thin-film photovoltaic and photoelectrochemical cells. However, efficiency of these devices based on existing metal oxides is typically low due to poor material properties. In this research, novel Sb:SnO2 nanorod and nanotube electron collectors have been synthesized, investigated and were used to improve the photo-conversion efficiency of top-performing BiVO4 photoelectrochemical cell. The performance of Sb:SnO2/BiVO4 photoanode achieved a new record for the product of light absorption and charge separation efficiencies (ηabs × ηsep) of ~ 57.3% and 58.5% under front- and back-side illumination at 0.6 VRHE and Sb:SnO2/BiVO4 PV cell achieved 1.22% solar power conversion efficiency. In addition, a new promising metal oxide material (CuBiW2O8) has been synthesized and its optoelectronic properties have been investigated to make photovoltaic cell which has potential to achieve over 30% solar power conversion efficiency.

O bagaço de cana-de-açúcar é um resíduo proveniente da agroindústria da cana-de-açúcar. Trata-se de um material biodegradável, com baixo custo e apresenta afinidade por compostos orgânicos e metais tóxicos. Neste trabalho preparou-se o bagaço de cana-de-açúcar combinado com nanopartículas de magnetita, o qual foi chamado de biossorvente magnético. A magnetita foi sintetizada por precipitação simultânea adicionando-se uma solução de NaOH à solução aquosa contendo Fe2+ e Fe3+. O material foi caracterizado por microscopia eletrônica de varredura, espectrometria de infravermelho por transformada de Fourier, análise termogravimétrica, difratometria de raios-X e medidas de magnetização. O biossorvente magnético apresentou uma alta magnetização de saturação sem histerese, comportamentos atribuídos aos materiais superparamagnéticos. Estudaram-se as variáveis do processo de adsorção de íons uranilo pelo biossorvente magnético em meio nítrico. O estudo do tempo de equilíbrio indicou um aumento de adsorção em função do tempo. Verificou-se que quanto menor o tamanho do biossorvente, maior a porcentagem de remoção. A máxima remoção ocorreu em pH 5. O aumento da velocidade de agitação do sistema soluto mais biossorvente favoreceu a adsorção, sendo encontrado o equilíbrio a partir de 300 r.p.m. Verificou-se que o aumento da dose de biossorvente magnético aumentou a remoção até tornar-se constante a partir de 10 g.L-1. Estudou-se a isoterma de equilíbrio segundo os modelos de Langmuir e Freundlich. O modelo de isoterma de Langmuir correlacionou-se melhor aos dados experimentais. A capacidade máxima de adsorção encontrada foi de 17 mg de U por g de biossorvente. Os mesmos estudos de adsorção foram realizados com o biossorvente de bagaço a fim de comparar os resultados. / Sugarcane bagasse is a residue from the sugarcane agroindustry. It is a biodegradable material, with low cost and presents affinity for organic compounds and toxic metals. In this work, the sugar cane bagasse combined with nanoparticles of magnetite was prepared and called magnetic biosorbent. The magnetite was synthesized by simultaneous precipitation by addition a solution of NaOH to the aqueous solution containing Fe2+ and Fe3+. The material was characterized by scanning electron microscopy, Fourier Transformer Infrared Spectroscopy, thermogravimetric analysis, X-ray diffractometry and measurements of magnetization. The magnetic biosorbent showed a high magnetization of saturation without hysteresis, behavior attributed to superparamagnetic materials. Variables of adsorption process of uranyl ions by magnetic biosorbent in nitric solutions were investigated. The study of the equilibrium time indicated an increase in the adsorption in function of time. Smaller biosorbent particle sizes resulted in greater removals. The maximum removal occurred at pH 5. The increase of stirring speed of the solute plus biosorbent system favored the adsorption, reaching the equilibrium at 300 r.p.m. The increase of the biosorbent dosage increased the removal, which became constant for doses above of 10 g.L-1. The equilibrium isotherm was verified according to the Langmuir and Freundlich adsorption isotherm models. The results correlated better to the Langmuir isotherm model, being found a value of maximum capacity of adsorption of 17 mg of U per g biosorbent. The same studies of adsorption were performed with the bagasse biosorbent in order to compare the results.

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016. / The subject of this current study concerns highly concentrated emulsions of the explosive grade. A distinguishing characteristic of these systems is a high internal to external phase volume ratio. The volume fraction of the aqueous phase of such an emulsion generally far exceeds the close packing limit. Continuous phase of the system is a supersaturated aqueous solution of ammonium nitrate inorganic salt. In combination with high internal phase concentration, this inevitably leads to the destabilisation of the system. The thermodynamic instability of such systems is attributed to two major factors: 1) crystallisation of dispersed phase and 2) coalescence of the individual droplets within the bulk. This poses a significant problem since destabilisation of the bulk emulsion in turn leads to partial or complete loss of sensitivity to detonation of the final product of which highly concentrated emulsion is the base. Since the invention of such types of bulk explosives, a considerable and on-going effort has targeted the improvement of the stability of these systems, with a scope primarily focused on the use of various surfactant agents with different properties as well as stabilising mixtures containing numerous surfactants. In recent years, a new approach has been explored: the stabilisation of highly concentrated emulsions with the use of solid fumed silica nanoparticles. This is a promising new field of study, already being implemented by manufacturers and actively developing. The focus of this present study is to investigate and lay the ground work for further research in the principally new approach towards the stabilisation of highly concentrated emulsions with the use of the polyhedral oligomeric silsesquiozane nanomolecules. These are unique compounds possessing hybrid inorganic-organic structures and properties, and carrying a range of advantages over currently implemented surfactants. As opposed to silica nanoparticles, these compounds are not solid particles but can be regarded as molecular silica. This investigation will focus on the general possibility of implementation of such compounds as stabiliser agents for emulsions in general, and highly concentrated emulsions of the explosive grade in particular, and the resultant effects on the stability. Effects on stability will be investigated both when used solely and in combination with common surfactants. In addition, stability both on shelf and under stress will be investigated within the framework of the study.

表面等離子體基元共振是自由電子在納米尺寸的集體共振效應，該效應會產生一系列新奇的性質。貴金屬納米結構由於可以產生表面等離子體基元共振而受到各個領域廣泛的關注。在共振激發的情況下，貴金屬納米結構具有極大的散射和吸收截面積以及極強的進場放大效應。這些奇特的性質可以應用於傳感、成像、光學調製、光熱療、光催化和太陽能電池等領域。金和銀納米結構由於其表面等離子體基元共振波長處在可見和近紅外波段而受到廣泛研究。然而，在某些應用中純金或純銀納米結構不能起到很好的作用。例如，金和銀對很多化學反應的催化活性很弱或者沒有催化活性。如果把金和銀與其他金屬複合在一起就可以同時獲得表面等離子基元共振和其他效應。在我的博士研究期間，我製備了Au/Ag 和Au/Pd 複合雙金屬納米結構和研究了該複合結構的表面等離子體基元共振的性質和在氫氣傳感和光催化中的應用。 / 由於在金屬納米結構的製備中晶種起著至關重要的作用，所以我首先研究了晶種的晶體結構和形狀對雙金屬納米結構合成的影響。我研究了銀和鈀分別在相同條件下在單晶金納米棒、多晶金納米棒和納米雙錐種子上的生長過程。研究發現當晶種是單晶金納米棒時，銀和鈀的生長形成長方體雙金屬納米結構。然而，當晶種是多晶的金納米棒和納米雙錐時，銀和鈀的生長生成納米棒雙金屬結構。銀和鈀在多晶金納米棒上的生長由兩端開始，而在多晶金納米雙錐上的生長由臺階面開始。這表明在雙金屬納米結構的生長過程中納米晶種的晶體結構對最終納米結構的形貌具有決定性的作用，而納米晶種的形狀對生長動力學有明顯的影響。 / 在Au/Ag納米晶製備過程中，我發現Au/Ag納米晶具有四個表面等離子體基元共振峰。於是我對這四個共振峰的演變和共振模式進行了實驗和理論研究。電動力學模擬表明能量最低的共振峰是縱向的電偶極共振，能量次低的共振峰是沿橫向的電偶極共振，兩個高能量的共振峰是沿著橫向的電八極共振。遲滯效應和兩個垂直橫向激發的干涉是導致形成兩個電八極共振的關鍵因素。研究發現隨著銀殼厚度的增加，縱向電偶極共振峰藍移，橫向電偶極共振峰先藍移后稍微紅移，兩個電八極共振沒有明顯的峰位移動。四個表面等離子體基元共振的強度都隨著銀殼厚度的增加而增強。 / 鈀被廣泛地應用於氫氣傳感和催化反應中。於是我研究了Au/Pd 雙金屬納米結構的氫氣傳感和光催化性能。在氫氣傳感研究中，我製備了兩種不同結構的Au/Pd 納米結構。一種具有連續的鈀殼層，另一種鈀殼層不連續。對於具有連續鈀殼層的納米結構，氫氣的傳感性能隨著鈀殼層厚度的增加而增加。實驗發現當納米結構暴露在4%的氫氣中時表面等離子體基元共振峰移動高達56 nm。不連續鈀殼層的納米結構的氫氣傳感性能不如連續鈀層的納米結構。我進一步對Au/Pd 雙金屬納米結構的光催化性能進行了研究。所選取的催化反應是Suzuki 偶聯反應。研究結果表明Au/Pd 納米結構可以有效地捕獲光能來促進化學反應。由於Au/Pd 納米結構使表面等離子體基元共振功能和催化功能緊密集成在一個納米結構中，因此表面等離子基元共振部份所捕獲的光能可以有效地傳遞到催化功能部份而實現光催化。研究發現熱電子效應和光熱轉化效應同時加速化學反應。其中光熱轉化在我的實驗中體現為非局部加熱效應，熱電子對化學反應的促進作用依賴于環境溫度。因此，光熱轉化效應可以促進熱電子轉移效應。 / 本論文的研究結果有助於人們瞭解具有表面等離子體基元共振性質的雙金屬納米機構的設計和應用。對Au/Ag雙金屬納米結構表面等離子體基元共振性質的研究不僅加深了人們對雙金屬表面等離子體基元共振的瞭解而且對利用不同共振模式實現特定功能有著指導意義。對Au/Pd雙金屬納米結構在氫氣傳感和催化反應應用中的研究明確表面雙金屬表面等離子體納米結構可以實現單一組成不具備的功能，這在一定程度上有助於擴展表面等離子基元共振在生命科學、能源和環境領域的應用。 / Noble metal nanocrystals have attracted great interest from a wide range of research fields because of their intriguing properties endowed by their localized surface plasmon resonances, which are the collective oscillations of free electrons. Under resonant excitation, metal nanostructures exhibit very large scattering and absorption cross sections and large near-field enhancement. These extraordinary properties can be used in different applications, such as plasmonic sensing and imaging, plasmon-controlled optics, photothermal therapy, photocatalysis, solar cells, and so on. Gold and Silver nanocrystals have plasmon resonances in the visible and near-infrared regions. However, gold and silver are not suitable for some applications. For example, they are generally inactive for catalyzing chemical reactions. The integration of plasmonic metals with other metals can offer superior or new physical/chemical properties. In this thesis, I prepared Au/Ag and Au/Pd bimetallic nanostructures and studied their lasmonic properties and applications in hydrogen sensing and photocatalysis. / Seeds have a crucial importance in the synthesis of bimetallic nanostructures. I therefore first studied the roles of the crystalline structure and shape of seeds on the overgrowth of bimetallic nanostructures. The overgrowth of silver and palladium on single crystalline Au nanorods, multicrystalline Au nanorods, and nanobipyramids were studied under the same conditions for each metal. The growths of silver and palladium on single crystalline Au nanorods gave cuboidal nanostructures, while rod-shaped nanostructures were obtained from the growths of silver and palladium on multicrystalline Au nanorods and nanobipyramids. Moreover, the growths of silver and palladium on multicrystalline Au nanobipyramids started at the stepped side facets, while the growths started at the twin boundaries on multicrystalline Au nanorods. These results unambiguously indicate that the crystalline structure of seeds plays a significant role on the final morphologies of multimetallic nanostructures, while the seed shape has a prominent effect on the growth kinetics. / Four plasmon resonance bands were observed in Au/Ag bimetallic nanocrystals. I then studied the evolution and nature of the four plasmon bands during the silver coating on Au nanorods both experimentally and theoretically. Electrodynamic simulations revealed that the lowest-energy peak belongs to the longitudinal dipolar plasmon mode, the second-lowest-energy peak is the transverse dipolar plasmon mode, and the two highest-energy peaks can be attributed to octupolar plasmon modes. The retardation effect and the interference between two perpendicularly polarized excitations along the edge directions are important for the formation of the distinct highest-energy and second-highest-energy octupolar plasmon modes, respectively. As the Ag shell thickness is increased, the longitudinal plasmon mode blue-shifts, the transverse plasmon mode first blue-shifts and then red-shifts slightly, and the two octupolar plasmon modes stay at nearly constant wavelengths. The extinction intensities of all the four plasmon bands increase with the increase of the overall particle size. / Palladium is widely used in hydrogen sensing and catalysis. I therefore studied the applications of Au/Pd bimetallic nanostructures in hydrogen sensing and photocatalysis. Two types of Au/Pd bimetallic nanostructures, nanostructures with continuous and discontinuous Pd shells, were employed to study their hydrogen sensing performances. For the nanostructures with continuous Pd shell, the hydrogen sensing performances were improved with the increase in the Pd shell thickness. A plasmon shift of 56 nm was observed when the hydrogen concentration was 4%. The nanostructures with discontinuous Pd shell exhibited smaller plasmon shifts compared with those with continuous Pd shell. For the photocatalytic application of Au/Pd bimetallic nanostructures, I studied their photocatalytic performance for Suzuki coupling reactions. The results indicate that plasmonic Au/Pd bimetallic nanostructures can efficiently harvest light energy for chemical reactions. The intimate integration of plasmonic and catalytic components in one nanostructure enables the light energy absorbed by the plasmonic component to be directly transferred to the catalytic component. Both hot electron transfer and photothermal heating contribute to the plasmon-enhanced chemical reactions. The photothermal effect is a nonlocal heating and the contribution of the hot electron transfer effect is dependent on the environmental temperature. Therefore, the photothermal heating effect can promote the hot electron transfer effect. / I believe that my research work will be very helpful for the design and application of plasmonic bimetallic nanostructures. My study on the plasmonic properties of Au/Ag bimetallic nanocrystals has deepened the understanding of the plasmons of Au/Ag nanorods and will be helpful for utilizing the different modes to achieve specific functions. The hydrogen sensing and photocatalysis of Au/Pd bimetallic nanostructures have shown that the integration of functional components with plasmonic nanostructures can achieve unconventional properties, which will flourish the applications of plasmons in life sciences, energy, and environmental areas. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Jiang, Ruibin = 雙金屬納米結構表面等離子體基元共振的研究及其在氫氣傳感和化學反應中的應用 / 江瑞斌. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references. / Abstracts also in Chinese. / Jiang, Ruibin = Shuang jin shu na mi jie gou biao mian deng li zi ti ji yuan gong zhen de yan jiu ji qi zai qing qi chuan gan he hua xue fan ying zhong de ying yong / Jiang Ruibin. / Abstract --- p.I / Acknowledgements --- p.VI / Table of Contents --- p.VIII / List of Figures --- p.X / List of Tables --- p.XIII / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Localized surface plasmon resonances --- p.1 / Chapter 1.2 --- Applications of localized surface plasmon resonances --- p.3 / Chapter 1.3 --- Overview of this thesis --- p.13 / Chapter 2 --- Theory, Simulation, and Experimental Methods for the Investigation of LSPRs --- p.20 / Chapter 2.1 --- Theoretical methods --- p.20 / Chapter 2.2 --- Simulation methods --- p.30 / Chapter 2.3 --- Experimental methods --- p.35 / Chapter 3 --- Preparation of Metal Nanostructures --- p.43 / Chapter 3.1 --- Preparation methods for Au nanocrystals --- p.43 / Chapter 3.2 --- Seed-mediated growth method --- p.46 / Chapter 3.3 --- Metal nanostructure preparations --- p.54 / Chapter 4 --- Crystalline Structure-Determined Growth of Bimetallic Nanocrystals --- p.62 / Chapter 4.1 --- Au nanocrystal seed preparation --- p.64 / Chapter 4.2 --- Au/Ag bimetallic nanocrystals --- p.66 / Chapter 4.3 --- Au/Pd bimetallic nanocrystals --- p.71 / Chapter 4.4 --- Summary --- p.77 / Chapter 5 --- Plasmons of Au/Ag Core/Shell Bimetallic Nanocrystals --- p.83 / Chapter 5.1 --- Variations of plasmons with Ag shell thickness --- p.86 / Chapter 5.2 --- Nature of the different plasmon modes --- p.94 / Chapter 5.3 --- Summary --- p.99 / Chapter 6 --- Au/Pd Bimetallic Nanostructures for Hydrogen Sensing --- p.105 / Chapter 6.1 --- Au nanorods with continuous Pd shell for hydrogen sensing --- p.107 / Chapter 6.2 --- Au nanorods with discontinuous Pd shell for hydrogen sensing --- p.114 / Chapter 6.3 --- Theoretical simulations --- p.117 / Chapter 6.4 --- Summary --- p.119 / Chapter 7 --- Plasmon-Enhanced Chemical Reactions --- p.124 / Chapter 7.1 --- Mechanisms of plasmon enhancement in chemical reactions --- p.125 / Chapter 7.2 --- Plasmon-enhanced Suzuki coupling reactions --- p.129 / Chapter 7.3 --- Summary --- p.149 / Chapter 8 --- Conclusions --- p.156 / Curriculum Vita --- p.160

如何在納米結構中控制的光的傳播，一直是物理和應用技術方面被廣泛研究的其中一個課題。在這篇論文中，我們從理論上探討在納米結構中表面等離子體激元(Surface plasmon polariton) 的特性以及其雜化。我們研究的納米結構包括金屬電介質金屬平板導波(chirped metaldielectric wave-guides) ，慘入納米金屬球的金屬電介質平板導波(metal dielectric waveguides with metallic narnoparticle doped)與光子晶體(photoniccrystals) 。 / 金屬-電介質-金屬平板導波由三層的金屬及電介質平板所組成，原本各自獨立存在於兩層金屬-介電介面的表面等離子體激元在兩層介面相距足夠近的情況下，會產生稱合作用而導致雜化表面等離子體激元(Hybridizedsurface plasmon polariton) 的產生，並且能在色散關係中被一條接近平坦、位於中頻附近的帶所表示。 / 同樣地，透過在金屬介電介面附近的電介質平板部份中加入納米金屬球，我們也能引起納米金屬球上的表面等離子體與平面金屬-介電介面上的表面等離子體激元之間的耦合作用，從而在色散關係產生另一條分支帶。 / 這些由雜化作用所導致的平坦的分支帶，其特性很容易透過操縱模型參數所改變。因此，我們可以在模型中引入一個介電常數(或厚度)的漸變梯度，從而達成表面等離子體激元的定域化，或多頻率表面等離子體激元(SPP rainbow) 的誘捕。 / 另外，透過轉移距列(transfer matrix)及哈密頓光學(Hamiltonian opticsapproach) 的應用，我們同時研究了表面等離子波在一維二元光子晶體中的斜入射色散關係及其傳播。結果證明，它可以用來引起波長尺度級別的表面等離子波的軌跡彎曲。 / Controlling the light propagation in nanostructures is one of the extensively studied topics in physics and technology. In this thesis, we theoretically investigate the behaviours of surface plasmon polariton (SPP) and the hybridized nanostructures, which include chirped metal-dielectric waveguides, metal-dielectric waveguides with metallic nanoparticle doped and photonic crystals. / In the system of chirped metal-dielectric waveguides which compose of metal-dielectric-metal multilayers, the evanescent coupling of the SPP waves at the two interfaces in the dielectric layer lead to a new hybridized surface plasmon polariton (HSPP) branch with a nearly flat dispersion at intermediate frequencies. / Similarly, by adding metallic nano-particles into the dielectric media, we can also achieve another HSPP branch which is caused by the coupling between the surface plasmon (SP) on the nanoparticles and SPP at the waveguide interface. Moreover, the nearly flat branch is tunable through changing the system parameters. Therefore by imposing a gradual variation of per-mittivity (or thickness), it is possible to achieve a localization of SPP wave, which is useful for achieving trapped SPP rainbow. / We also study at oblique incidence the dispersion relation and the propagation of SP in one dimension binary photonic crystals by using methods of transfer matrix and Hamiltonian optics approach. The result shows that it can be used to achieve a superbending of SP waves in wavelength scales. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chau, Cheung Wai = 表面等離子光學及納米光學中的雜交化電磁極化子 / 鄒長威. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 84-86). / Abstracts also in Chinese. / Chau, Cheung Wai = Biao mian deng li zi guang xue ji na mi guang xue zhong de za jiao hua dian ci ji hua zi / Zou Changwei. / Abstract --- p.i / 概要 --- p.iii / Acknowledgements --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Plasmonics and nanophotonics --- p.1 / Chapter 1.2 --- Surface plasmon polaritons --- p.2 / Chapter 1.2.1 --- History of SPP --- p.2 / Chapter 1.2.2 --- Investigations and applications of SPPs --- p.3 / Chapter 1.3 --- Objective of thesis --- p.3 / Chapter 2 --- Basic principles --- p.5 / Chapter 2.1 --- Drude model --- p.5 / Chapter 2.2 --- SPP formalism --- p.7 / Chapter 2.2.1 --- SPP excitation --- p.9 / Chapter 2.3 --- Level repulsion phenomenon --- p.10 / Chapter 2.3.1 --- Simple coupled oscillator --- p.10 / Chapter 2.3.2 --- Diatomic elastic chain --- p.12 / Chapter 2.3.3 --- Summary --- p.13 / Chapter 2.4 --- Transfer matrix method --- p.14 / Chapter 2.5 --- Hamiltonian optics approach --- p.16 / Chapter 2.6 --- Maxwell Garnett approximation --- p.17 / Chapter 3 --- Thomson plasmonics --- p.20 / Chapter 3.1 --- Introduction --- p.21 / Chapter 3.2 --- Model and scheme --- p.21 / Chapter 3.3 --- HSPP formalism --- p.22 / Chapter 3.4 --- HSPP bands with varying inclusions of metallic nanospheres --- p.23 / Chapter 3.5 --- Confinement scheme --- p.25 / Chapter 3.6 --- HO simulation and localization --- p.26 / Chapter 3.6.1 --- Center excitation --- p.28 / Chapter 3.6.2 --- Off center excitation --- p.30 / Chapter 3.7 --- Tunability and fabrication --- p.31 / Chapter 3.8 --- Complications and loss --- p.33 / Chapter 3.9 --- Summary --- p.33 / Chapter 4 --- Chirped metal-dielectric waveguides --- p.41 / Chapter 4.1 --- Introduction --- p.42 / Chapter 4.2 --- Model and scheme --- p.42 / Chapter 4.3 --- SPP formalism --- p.43 / Chapter 4.4 --- HSPP bands with varying permittivity and thickness --- p.45 / Chapter 4.5 --- Confinement scheme --- p.46 / Chapter 4.5.1 --- Varying permittivity --- p.47 / Chapter 4.5.2 --- Varying thickness --- p.47 / Chapter 4.6 --- Ho simulation and localization --- p.48 / Chapter 4.6.1 --- Varying permittivity --- p.49 / Chapter 4.6.2 --- Varying thickness --- p.51 / Chapter 4.7 --- Summary --- p.53 / Chapter 5 --- Dispersion and mirage of surface plasmon waves in metallic photonic crystals --- p.60 / Chapter 5.1 --- Photonic crystal --- p.60 / Chapter 5.2 --- Introduction --- p.61 / Chapter 5.3 --- Dispersion relation formalism --- p.61 / Chapter 5.4 --- Graded material --- p.64 / Chapter 5.5 --- Ho simulation --- p.65 / Chapter 5.6 --- Results --- p.66 / Chapter 5.6.1 --- Lowest band excitation --- p.66 / Chapter 5.6.2 --- Second lowest band excitation --- p.69 / Chapter 5.6.3 --- Multiangle incidence --- p.71 / Chapter 5.7 --- Summary --- p.72 / Chapter 6 --- Conclusion --- p.82 / Bibliography --- p.84

I believe that my research work will provide an in-depth understanding of the basic chemical and physical properties of plasmonic gold nanorods. These works can inspire future applications of plasmonic nanostructures on biotechnology, optoelectronics and solar energy conversion. - / I will first introduce my studies on high-index-faceted gold nanocrystals. Elongated tetrahexahedral (THH) gold nanocrystals have been prepared in high yields using a seed-mediated growth method. Structural characterizations reveal that they are single crystals enclosed by 24 high-index facets. Electrochemical measurements have proven that these THH Au nanocrystals are more chemically active than octahedral Au nanocrystals that are enclosed by low-index {1111} facets. Next, I will demonstrate the formation of large-area, 3D ordered assemblies of Au nanostructures that have different sizes and shapes, including nanorods, polyhedra, nanocubes, and bipyramids, by droplet evaporation. The nature of the resultant assemblies is strongly dependent on the shape of Au nanostructures for single-component systems; while the assembly of binary nanorod mixtures is dependent on the relative diameters of two nanorod samples for the nanorods used in our experiments. / Most applications of plasmonic nanostructures are based on their interactions with other chemical/physical species. In my research work, gold nanorods interacting with photochromic molecules and fluorophores are extensively studied. For the case of photochromic molecules, I have demonstrated a plasmonic switch on the basis of the resonance coupling between single Au nanorods and photochromic molecules. An individual plasmonic switch is composed of a single nanorod and the surrounding photochromic molecules. Its modulation depth reaches 7.2 dB. The estimated power and energy required for operating such a single-nanorod plasmonic switch are ∼13 pW and ∼39 pJ. For the case of fluorophores, I will give a systematic description of my research on plasmon-fluorophore interactions. Excitation polarization-dependent plasmon-enhanced fluorescence, polarized emission, and modulation of fluorophore emission spectra by localized plasmon resonances will be experimentally demonstrated. The interactions between the plasmonic nanorods and the fluorophore molecules can be temporally separated into plasmon-enhanced excitation and coupled emission processes under unsaturated excitation conditions. Finite-difference time-domain (FDTD) method will be employed to explain the origin of the excitation and emission polarization dependence. A term "plasmophore", which is corned by Lakowicz et al., is quoted to describe the artificially prepared quantum emitters that are composed of plasmonic structure and fluorophore. / Noble metal nanocrystals have drawn great attention in a wide range of research fields due to their extraordinary localized surface plasmon resonances, which are essentially collective charge density oscillations confined in metallic nanostructures. Their applications range from bioimaging, sensing and therapy in life sciences to plasmonic circuits and optical data storage in micro-optoelectronics. More attractively, they can be used to enhance light harvesting in solar energy conversion systems. In this thesis, I will systematically describe the preparation and assembly of gold nanorods and their interactions with fluorophores and photochromic molecules, both experimentally and theoretically. / Ming, Tian = 金納米棒的生長、組裝以及他們與螢光團或光至變色分子的相互作用 / 明天. / Adviser: Jianfang Wang. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Ming, Tian = Jin na mi bang de sheng chang, zu zhuang yi ji ta men yu ying guang tuan huo guang zhi bian se fen zi de xiang hu zuo yong / Ming Tian.