The fascinating physical properties that arise in materials limited to dimensions of 1-100 nm have gained noteworthy interest from the scientific community. Accordingly, there has been a lot of attention paid to the synthesis of discrete nanoparticles (NPs) and they are being investigated for a range of advanced technologies. Nonetheless, efficient use of nanomaterials in device applications require them to be assembled into solid state macro-structures while retaining their unique, nanoparticulate properties. To date, most commonly investigated assembling techniques include: covalent coupling of NPs surface groups, control evaporation of the solvent to produce ordered supercrystals or non-ordered glassy films, and polymer or bimolecular mediated self-assembly. However, in each of these cases, the interactions among discrete NPs are mediated by intervening ligands, the presence of which are detrimental for efficient electronic transport and interparticle coupling that limit performance in optoelectronic,electro-catalytic, and chemical sensor studies. Thus, novel and efficient strategies that can be predictably manipulated for direct, self-supported assembly of NPs are of critical need. A method that has proved useful to construct direct interfacial linkages of colloidal NPs is the sol-gel technique.Oxidative removal of surfactant ligands has been shown to produce self-supported NP monoliths that in most cases retain the physical properties of primary NPs.The ability to create direct interfacial bonds contributes to enhanced electrical and thermal transport as well as tunable interparticle interactions, expanding the potential range of NP technologies. During oxidation, low coordinated active sites are produced on the NP surface that interacts with a nearby NP to reduce the surface energy. The formed active sites are highly reactive allowing the NPs to establish direct interfacial linkages, polymerize into low dimensional clusters, and consequently highly porous superstructures that augment the unique, nanoparticulate properties. An added advantage of this chemistry is the ability to couple chemically similar or dissimilar systems with the potential to achieve novel/tunable physical properties. In this dissertation, application of sol-gel chemistry in efficient integration of similar and dissimilar nanoscale materials will be discussed with an aim of achieving improved optoelectronic and electro-catalytic properties. Hybrid nanomaterials composed of metal-semiconductor components exhibit unique properties in comparison to their individual counterparts, making them of great interest for optoelectronic technologies. The direct cross-linking of NPs via sol-gel chemistry provides a versatile route to tune interfacial interactions in a manner that has not been thoroughly investigated. Thus, the first part of the dissertation will illustrate the synthesis of CdSe/Ag hetero-nanostructures (aerogels) via oxidation induced self-assembly of thiol-coated NPs and investigate the evolution of optical properties as a function of Ag composition. Two hybrid systems were investigated, where the first and second excitonic energies of CdSe were matched with plasmonic energy of Au and Ag NPs. The optical properties of the CdSe/Ag hybrids were systematically examined through UV-visible, photoluminescence, and time resolved photoluminescence spectroscopy. A new emission (640 nm) from CdSe/Ag aerogels was emerged at Ag loading as low as 0.27 % whereas absorption band tailing and PL quenching effects were observed at higher Ag and Au loading, respectively. The TRPL decay time of the new emission (~600 ns) is markedly different from those of the band-edge (1.83 ± 0.03 ns) and trap state (1190 ± 120 ns) emission maxima of phase pure CdSe, supporting the existence of alternate radiative relaxation pathways in sol-gel derived CdSe/Ag hybrids. An added benefit of newly developed sol-gel chemistry is the potential to produce porous, conducting nanoarchitectures that provide a facile pathway for efficient transfer of charge carriers and small molecules. Thus, aerogels composed entirely of noble metal NPs are expected to exhibit high electrical conductivity making them promising for electrocatalysis. Thus, the second part of the dissertation will describe the extension of NP condensation strategy for the fabrication of ternary noble metal (Au/Ag/Pd, Au/Ag/Pt) aerogels for electro-oxidation of alcohols. The precursor alloy NPs were produced via stepwise galvanic replacement of thiol-coated Ag NPs. The resultant alloy NPs were self-assembled into large, free-standing aerogels that exhibit direct interparticle connectivity, high surface area (282 – 98 m2/g) and mesoporosity (2 – 50 nm) via controlled oxidation of the surfactant ligands. The gelation kinetics has been controlled by varying the oxidant/surfactant molar ratio that governs the dealloying of Ag from ternary superstructures with in-situ generated HNO3. The monolithic Au/Ag/Pd alloy aerogels exhibit higher catalytic activity and durability compared to the discrete alloy NPs (~ 20-30 times) and commercial Pd/C catalyst (2-3 times). On the other hand, Au/Ag/Pt alloy aerogels showed excellent stability at higher concentration of methanol (12 M) during electro-oxidation studies, suggesting its superior electro-catalytic activity. The synergistic effect of tri-metallic alloy mitigates the catalyst poisoning and increases the stability and durability whereas the self-supported superstructure with direct interparticle connectivity, high surface area and porosity offers a facile conduit for molecular and electronic transport, enabling the ternary aerogels an efficient electro-catalyst.

The rapid development of polymer nanocomposites has received extensive attention over the last few decades. The ability to alter functionalities of composites, dramatically improving properties and performance at low filler content creates flexibility in designing materials for advanced applications in various industrial fields. This work focuses on nanocomposites relevant to the packaging and aerospace industries. This work evaluated the ability to homogeneously distribute nanomaterials into a polymer matrix, understand the effects on rheological properties, understand changes to microstructure and effects, and characterize properties of resulting nanocomposite. High torque melt mixing was used to disperse surface modified cellulose nanocrystals in a poly(lactic acid) (PLA) resin and graphene in a phenylethynyl terminated imide resin, PETI 298, using bulk graphite. Rheology, Raman spectroscopy, and X-Ray powder diffraction were applied for the understanding of changes to the microstructure and location of optimum loading by the determination of the percolation threshold. Thermomechanical performance was evaluated through TGA, DMA, and DSC. It was determined that graphene and short stacks of graphene could be dispersed and distributed at low loadings in PETI 298. As expected, the addition of graphitic material led to an increase in viscosity, but also caused a retardation of the cure which could be attributed to increased viscosity or quenching of free radicals. Changes to the microstructure were difficult to evaluate because of the competing chemistry occurring in the system but it could be determined that something significant occurs around 1 wt % at which the melt rheology and the microstructure behavior was different from other composites. It was further determined that the melt mixing process led to the formation of an ordered structured. Modification of the cellulose nanocrystals (m-CNC) with Cardura, glycidyl ester, provided no improvement to mechanical properties of PLA composites. However, m-CNCs were found to nucleate the crystallization of PLA. Lack of improvement to mechanical properties could be attributed to the degradation of polymer during processing.

Phloridzin, an antidiabetic and antineoplastic agent usually found in fruit trees, is a dihydrochalcone constituent that has a clinical/pharmaceutical significance as a sodiumglucose linked transport 2 (SGLT2) inhibitor. Phloridzin never experienced widespread clinical usage in the pharmaceutical market due to its side effects and poor bioavailability when compared to other antidiabetic therapeutics. The poor bioavailability is primarily attributed to the degradation of the glycosidic bond of the phloridzin, resulting in the formation of phloretin, the aglycone of phloridzin and glucose. While phloretin displays a reduced capacity of SGLT2 inhibition, this nutraceutical shows enhanced antineoplastic activity in comparison to phloridzin. Gold nanoparticles (AuNPs) have been explored in improving the bioavailability of many drugs and therefore we opt for gold nanoparticle mediated delivery of phloridzin and phloretin and exploration of their anticancer mechanism. In this study, we have synthesized phloridzin and phloretin conjugated gold nanoparticles (Phl-AuNP and Pht-AuNP) in a single-step, rapid, biofriendly processes. The synthesized AuNPs morphology and elemental composition was characterized via transmission electron microscopy, UV-Vis spectroscopy, scanning electron microscopyenergy dispersive x-ray spectroscopy, and thermogravimetric analysis. Assessment of the antineoplastic potency of the dihydrochalcone-conjugated AuNPs against cancerous cell lines was accomplished through monitoring via flow cytometry. We posit that the functionalization of these chalcones onto the gold nanoparticles’ surface has improved the pharmacokinetic profile of phloridzin and phloretin.

Solid catalyst supports of SiOx-RGO (Reduced Graphene Oxide) and UiO-67 (Universitet i Oslo) have been successfully synthesized and were loaded with palladium nanoparticles to test for a series of heterogeneous reactions. The SiOx/RGO catalysts were synthesized through laser ablation of silicon and graphite oxide micron powder and UiO-67 metal-organic framework (MOF) was synthesized through mixing of precursors with DMF/HCl solution and washing the resultant powder from impurities. The SiOx/RGO supports were later impregnated with palladium precursors which were then subject to Microwave Irradiation (MWI). The UiO-67 framework was impregnated with palladium precursors and was irradiated with pulsed Nd:YAG 532 nm laser and was purified through washing and centrifugation. The resulting catalyst supports were characterized with UV-Vis, FTIR, Raman, XRD and XPS techniques and the UiO-67 framework was subject to Brunauer-Emmet-Teller (BET) surface area measurements before and after the catalytic reactions. The catalytic activity of palladium nanoparticles supported on SiOx/RGO and UiO-67 framework was tested in carbon cross-coupling reactions of Suzuki-Miyaura, Sonogashira reactions and oxidation of benzyl alcohol respectively. The catalysts have demonstrated excellent performance and have yielded a promising future for the catalytic supports in the previously stated reactions.

A series of oxide materials were modified with different nanoparticles (NPs). Novel cobalt@H4Nb6O17 nanopeapod structures were fabricated and magnetic NPs modified oxide nanosheets and nanoscrolls were prepared. Both aqueous method and two-phase method were applied to prepare gold NPs onto oxide nanosheets, nanoscrolls and other nanocrystals. The combination of H4Nb6O17 nanoscrolls and cobalt NPs generate a novel method to fabricate nanopeapod structures. Cobalt NPs were synthesized in the presence of exfoliated H4Nb6O17 nanosheets and the resulting magnetic chain structures, formed due to the dipole-dipole interaction, were captured within scrolled lamella. The yield of peapod structures can be improved by using proper reagents and reaction temperatures. As similar method with iron oxide NPs also produced peapod-like structures in a low yield. Exfoliated Dion-Jacobson phase layered perovskite HLaNb2O7 (HLN), its organic derivate propoxyl-HLaNb2O7 (pHLN), Ruddlesden-Popper phase perovskite H2SrTa2O7 (HSTO) and Aurivillius phase perovskite H2W2O7 (HWO) were synthesized and functionalized with gold NPs by in-situ methods. Gold NPs were prepared by both an aqueous method and two-phase method. The size of NPs can be adjusted by different reaction times. Overall, the latter method shows a narrower size distribution and better dispersion. In addition, most gold NPs prepared by the two-phase method were attached on the surface of nanosheets and almost no free gold NPs were observed in solution. This approach should be applicable to most layered perovskites. The aqueous and two-phase methods were also applied on the preparation of gold NPs onto H4Nb6O17 nanosheets and nanoscrolls. H4Nb6O17 nanosheets were prepared by two approaches and showed similar gold NPs attachment. LiNbO3 nanocrystals can be also modified with gold NPs by the two-phase method though free gold NPs were observed. Further studies involved the functionalization of layered perovskites and related compounds with magnetic NPs. Iron oxide and cobalt NPs were synthesized in the presence of layered perovskite and modified perovskite nanosheets were obtained.

Manganese-Aluminium is an alloy with attractive ferromagnetic propertieswhenL10-structured ( -phase). If sucient permanent magnetic propertiescan be achieved at a low cost, it has potential to be a new permanentmagnet material on the market. In this thesis, drop synthesized ingots ofMn55Al45C2 were crushed and examined as solid pieces and as powders.The goal was to better understand how the material behaves magneticallyafter synthesis in relation to its chemical composition and cooling rate. Representativecross-sections of solid ingot pieces were created by mounting thepieces in polyfast followed by polishing. The surfaces were studied withScanning Electron Microscopy and Energy-dispersive X-ray spectroscopy tomap the chemical composition and then by Magnetic Force Microscopy andMagneto-optic Kerr eect to see how the chemical composition inuencesthe magnetic properties. It was found that areas richer in aluminium (Al),compared with the rest of the surface, behaved non-magnetically. The resultsfrom X-ray diraction on the powders suggests that the Al-rich areasconsists of the non-magnetic- and 2-phases.The powder that was extracted from the top of one of the drop synthesizedingots was nearly pure -phase but did not have an impressive magnetization.A complementary magnetic measurement was done on a solid piece from thetop part. This piece was found to reach a higher magnetization at a lowereld. The result indicates that crushing the material, even just by hand witha mortar and pestle, greatly reduces the magnetization.

The thesis has dealt with transparent conducting oxide (TCO) materials, with a focus on Al:ZnO and with studies on Sn:In2O3 and ZnO. TCOs are a material group that is used for its properties of being conductive and at the same time transparent. In solar cells, a top layer of TCO is often used to allow light to transmit into the cell and then conduct the resulting current.   A set of growth parameters was chosen and optimized through a literature study and experiments. The depositied thin films were characterized by optical and electrical characterization methods. Rf-magnetron-sputtering was used as the deposition method, where the influence of O2, argon and substrate temperature were the parameters to be studied. As a part of the characterization a model for spectroscopic ellipsometry on Al:ZnO was made, enabling faster measurement of transport properties. The main parameter affecting the TCO properties was found to be oxygen flow and the optimum flow value for each material has been determined. Substrate heating did not show any significant improvement on the resistivity of Al:ZnO with a minimum value of ~5.0*10-4 Ωcm while no heating resulted in a value of ~6.0*10-4  Ωcm. These values are comparable to the state-of-the-art from the literature.   As a demonstration of application, the developed AZO and ZnO were applied to CIGS solar cells and these were compared to a reference. The newly developed AZO and ZnO was comparable to the reference but a lower mean fill factor indicates that improvements can be made.

Iron oxides, have been widely studied as promising anode materials in lithium-ion batteries (LIBs) for their high capacity (≈ 1000 mA h g-1 for Fe2O3 and Fe3O4,), non-toxicity, and low cost. In this work, β-FeOOH has been evaluated within a LIB half-cell showing an excellent capacity of ≈ 1500 mA h g-1 , superior to Fe2O3 or Fe3O4. Reaction mechanism has been proposed with the assistance of X-ray photoelectron spectroscopy (XPS). Various magnetic properties have been suggested for β-FeOOH such as superparamagnetism, antiferromagnetism and complex magnetism, for which, size of the material is believed to play a critical role. Here, we present a size-controlled synthesis of β-FeOOH nanorods. Co-existing superparamagnetism and antiferromagnetism have been revealed in β-FeOOH by using a Physical Property Measurement System (PPMS). Compared with the high price of lithium in LIBs, sodium-ion batteries (SIBs) have attracted increasing attentions for lower cost. Recent studies have reported Na0.44MnO2 to be a promising candidate for cathode material of SIBs. This thesis has approached a novel solid-state synthesis of Na0.44MnO2 whiskers and a nano-scaled open cell for in situ TEM study. Preliminary results show the first-stage fabrication of the cell on a biasing protochip.

The design and development of nanoparticles is of great interest in the current energy and electronic industry. However, based on the current materials available the production cost can be high with insignificant magnetic and mechanical properties. Specifically, rare-earth magnetic materials composed of neodymium and samarium are known for their high magnetic performance, however, due to the cost of development there is a need to develop a versatile and cost effective material. Alternatively, cobalt carbide nanomaterials have shown to be a promising alternative for rare-earth free magnets as they exhibit comparable properties as hexaferrite magnetic materials. The primary goal of this dissertation focuses on the development of nanoparticles for permeant magnetic, and magnetic refrigeration applications. The first part of this work focuses on the synthesis of cobalt carbide (CoxC, x=2,3) nanoparticles using a novel polyol synthesis method by introducing a small amount of Ru, Cu, or Au as nucleating agent. It was found that the morphology and magnetic properties of the as-synthesized CoxC nanoparticles change as a result of directional growth of nanoparticles using nucleating agents. Needle-like particle morphology ranges from 20-50 nm in width and as long as 1 µm in length were synthesized using Ru as nucleating agent. These particles exhibit magnetization saturation of 33.5 emu/g with a coercivity of 2870 Oe and a maximum energy product 1.92 MGOe (BHmax) observed. Particle morphology is a critical aspect in the development of magnetic nanoparticles as anisotropic particles have shown increased coercivity and magnetic properties. These CoxC nanomaterials have a higher maximum energy product compared to previous work providing further insight into the development of non-rare earth magnetic material. The second part of this dissertation work focuses on the sol-gel synthesis of perovskite LaCaMnO3 (LCMO) nanomaterials. In this process, various chain lengths of polyethylene glycol (PEG) was added into a solution consisting of La, Ca, and Mn salts. The solution was left for the gelation process, and high temperature sintering to obtain the final product. By varying the polymer chain of the PEG, the size of the as synthesized LaCaMnO3 nanomaterials were altered. The as-synthesized LCMO nanomaterials have shown a maximum change in magnetic entropy (-ΔSM) was found to be 19.3 Jkg-1K-1 at 278 K for a field change of 0-3 T and 8.7 Jkg-1K-1 for a field change of 0-1 T. This is a significant improvement in comparison to current literature of the material suggesting that this is a promising alternative to Gd materials that is prone to oxidation. With additional development, LCMO or related maganites could lead to application in commercial technologies.

The importance of porous materials has risen substantially in the last few decades due to their ability to reduce the size and cost of bioanalytical devices and fuel cells. First, this work aims to describe the fabrication of nanoporous gold (NPG) electrodes that are resistant to electrode passivation due to fibrinogen biofouling in redox solutions. The effect on potentiometric and voltammetric experiments was seen as a deviation from ideal behavior on planar gold electrodes, whereas NPG electrodes were consistently behaving in a Nernstian fashion at low concentrations of ferri-ferrocyanide (£100 mM). An improvement in electrode behavior on NPG electrodes versus planar gold was seen in solutions containing ascorbic acid as well as blood plasma. Second, cost effective NPG electrodes were fabricated using a glass substrate to test the response in the presence of a variety of redox molecules. The optical transparency of these electrodes allowed for microdroplet measurements to be made using an inverted microscope in several redox solutions for validation and subsequent biological applicability. Nernstian behavior was demonstrated for all one- and two-electron transfer systems in both poised and unpoised solutions. All experiments were conducted using volumes between 280 and 1400 pL producing rapid results in less than one minute. Third, in order to decrease the requirement for complex instrumentation, microdroplet fabrication technique was used to create mini-nanoporous gold (mNPG) electrodes on glass capillary tubes. The cylindrical shape of the electrodes allowed for testing in sample volumes of 100 mL. The response to ferri-ferrocyanide, ascorbic acid, cysteine, and uric acid was then investigated with Nernstian behavior shown. However, the mNPG electrodes were insensitive to glucose and hydrogen peroxide. In order to increase the sensitivity of the electrodes, a minimal amount of platinum was electrodeposited onto the NPG surface using a low concentration of platinum salt (0.75 mM) for a short deposition time (2 seconds) producing a Nernstian response to both glucose and hydrogen peroxide. Lastly, to test the viability of crossover applications, the platinum incorporated NPG electrode was employed as a fuel cell anode material, testing their oxidation capability with methanol, ethanol, and formic acid.