Different kinds of nanoparticles are widely used in optoelectronic and photovoltaic applications to harvest light to increase efficiency of devices. ETS-10, which is a synthetic microporous material consisting of &ndash / Ti-O-Ti-O-Ti- wires that run in the crystal in a and b directions, has been of interest in such applications due to its unique properties. In the current study, the synthesis conditions of ETS-10 were investigated in order to obtain pure ETS-10 crystals with the desired morphology. For this purpose, ETS-10 crystals were synthesized using different molar compositions. The effects of several synthesis parameters on the obtained products were investigated. Furthermore, ETS-10 thin films were prepared on ITO glass substrates using secondary growth of ETS-10 for the first time. The orientation of the -Ti-O-Ti-O-Ti- wires inside ETS-10 were explored by preparing several ETS-10 films on the ITO glass substrates using secondary growth of ETS-10 multilayers with a partial a(b)-out-of-plane preferred crystal orientation. This orientation can be desirable for the advanced applications of ETS-10 films. Afterwards, silver nanoparticle modified ETS-10 crystals were prepared and characterized in detail to understand the interaction of silver nanoparticles with the synthesized ETS-10 crystals. For this purpose, ETS-10 in the as-prepared and silver nanoparticle containing forms have been characterized using, XRD, ICP-OES, SEM, HR-TEM, N2 Adsorption, XPS, and UV/VIS spectroscopy. In order to investigate the optical properties of the silver modified ETS-10, transmittance-reflectance measurements were carried out. In general, it is believed that all steps necessary for the preparation of ETS-10 films and preliminary steps for investigating ETS-10 for future photovoltaic applications were determined.

Darbe tirtos funkcionalizuotų dendrimerų optinės savybės sintetinant sidabro nanodaleles panaudojus glikodendrimerą kaip terpę. Keičiant išorinius faktorius, tokius kaip temperatūra (20 oC ir 45 oC), medžiagų koncentracija (1:5, 1:10 ir 1:20) ar skirtingo bangos ilgio šviesa (532nm ir 632,8nm), užauginome sidabro nanodaleles. Gauti rezultatai rodo, jog sidabro nanodalelių dydžiui didžiausią įtaką daro tik [dendrimeras/AgNO3] santykis. Kuo jis didesnis – tuo sidabro dalelės yra didesnės. Tuo tarpu tiek temperatūra, tiek šviesa didesnės reikšmės dalelių susiformavimui neturi. Remiantis gautais rezultatais galime tvirtinti, kad tirti PPI-G4 glikodendrimerai gali būti naudojami kaip matrica sidabro nanodalelių formavimui. / We prepared silver nanoparticles using a fourth-generation PPI glycodendrimer were about from 5nm to 10nm in size, and that the higher the [dendrimer/AgNO3] ratio, the larger were the metal particles. The results suggest that the temperature and different wavelength of light does not affect the nanoparticle size by using PPI-G4 glycodendrimer as a template. The characteristic absorption peak at around 400nm corresponds to a plasmon band. The splasmon spectrum of nanoparticles is affected by the nature of the metal and the status of aggregation of the particles. The single peak indicates that the silver particles are of spherical shape.

Interest in controlling the synthesis of silver nanoparticles in colloidal solutions has increased during the last two decades. There is also growing interest in forming layers of silver nanoparticles on substrates, particularly for surface-enhanced Raman spectroscopy applications. However, methods to grow silver nanoparticles directly on substrates have not been studied extensively, and there are few techniques for controlling the size, shape, density, and location of the particles. This work presents a simple and reliable method to photodeposit silver nanoparticles onto transparent substrates. The size, shape and deposition density of the nanoparticles are influenced by the precursor solution, light intensity, and surface modification of the substrate. This allows control of the optical and electrical properties of the nanoparticle films. Furthermore, the particles can be patterned using direct laser exposure, scanning probe methods, and electron-beam lithography. Applications and advantages of this deposition method are proposed and explored.

Nanoparticles (NPs) are engineered in the nanoscale (<100nm) to have unique physico-chemical properties from their bulk counterparts. Nanosilver (nAg) is the most prevalent nanoparticle in consumer products due to its strong antimicrobial action and can be released to the environment during product manufacture, usage and disposal. The predicted environmental concentrations are within the North American guidelines for the protection of aquatic life and in drinking water. While nAg toxicity at high concentrations has been well described, the sublethal effects at environmentally-relevant concentrations are relatively unknown. Initial screening in our lab showed nAg was a potential endocrine disrupting chemical (EDC). Amphibian metamorphosis is mediated by thyroid hormone (TH), and nAg perturbed TH-dependent transcriptional responses in the tailfin of bullfrog (Rana catesbeiana) tadpoles. The primary objective of this thesis was to further investigate and characterize the effects of low, environmentally relevant concentrations of nAg on TH-dependent metamorphosis in R. catesbeiana and Xenopus laevis. Two chronic, 28 day in vivo exposures at 0.06 and 6µg/L nAg were conducted with premetamorphic R. catesbeiana tadpoles using TH to induce precocious metamorphosis. Ionic silver (iAg) was also examined to control for the complete dissolution of Ag. Analysis of metamorphic stage progression demonstrated nAg-induced acceleration of hindlimb growth and development. After 6 days of nAg exposure, analysis with quantitative real-time polymerase chain reaction (QPCR) demonstrated nAg-induced disruption of TH-responsive transcripts in a tissue-specific manner. Furthermore, the nAg effects could not be fully explained by iAg, indicating NP-specific disruption. Two chronic, 28 day exposures to 0.018-1.8 µg/L nAg were conducted on X. laevis premetamorphic and prometamorphic tadpoles. nAg was found to significantly bioaccumulate in tadpole tissue after 28 days. Furthermore, nAg increased the hindlimb length during early premetamorphosis and in post-metamorphic juvenile tadpoles. Using an in-house MAGEX microarray and QPCR transcriptional analysis, 7 biomarkers of nAg exposure were validated. Five of these targets showed disruption to their TH-response. Furthermore, the increased mRNA abundance of two peroxidases indicated that nAg generated reactive oxygen species (ROS) even at low, environmental concentrations. This thesis demonstrates that nAg has consistent EDC actions across two distinct amphibian species, and the data suggest that regulatory guidelines for silver may need revision. A X. laevis derived fibroblast-like TH-responsive cell line, XTC-2, was used in conjunction with the 7 biomarkers of nAg exposure to gain mechanistic insight into the role of ROS in TH signaling disruption. Monocultures were created and validated to increase the specificity of TH-response. While the monocultures were successfully created, the biomarkers were not responsive to nAg in this cell line. Additional investigations were made into the relationship between genetic sex and responsiveness to TH. Genetic sexing methods were used to investigate transcriptional differences between males and females during natural and TH-induced metamorphosis. The sexing protocol was optimized and validated successfully. The genetic sex was determined for premetamorphic and prometamorphic X. laevis tadpoles exposed to TH for 48 h. QPCR and microarray analysis were used to identify three markers that demonstrated transcriptional sex-bias during early gonadal differentiation stages. / Graduate / 0307 / 0383 / 0487 / amanda_carew14@yahoo.ca

Plasmonic properties of self-assembled silver nanoparticles/nanowires array on periodically patterned Si (100) substrate are reported with special attention on the mechanism of nanoparticles self-assembly. The advantage of this bottom up approach over other self-assembling and lithographic methods is the flexibility to tune array periodicity down to 20 nm with interparticle gaps as low as 5 nm along the ripple. Ripple pattern have shallow modulation (~2 nm) still particles self-assembly was observed in non-shadow deposition. Therefore adatoms diffusion and kinetics is important on ripple surface for the self-assembly. PVD e-beam evaporation method used for deposition has proven to be superior to sputter deposition due to lower incident flux and lower atom energy. It was found that particles self-assembly largely dependent on angle of incidence, substrate temperature, and deposition direction due to ripple asymmetric tilt. Ostwald ripening observed during annealing on ripples substrate has striking dependency on ripple periodicity and was found to be different compared to Ostwald ripening on flat Si surface. In-situ RBS measurements of deposited silver on flat and rippled substrate confirmed different sticking of atoms on the two surfaces. The difference between maximum and minimum of the calculated local flux show a peak at an incidence angle of 70o with respect to surface normal. This explains the best alignment of particles at this angle of incidence compare to others. Self-assembled nanoparticles are optically anisotropic, i.e. they exhibit a direction dependent shift in LSPR. The reason of the observed anisotropy is a direction dependent plasmonic coupling. Different in plane and out of the plane dielectric coefficients calculated by modelling Jones matrix elements, confirms that nanoparticle/nanowire array are biaxial anisotropic (ex ¹ ey ¹ ez). The nanoparticles are predominantlyinsulating while nanowires are both metallic and insulating depending on the dimension. Silver nanoparticles/nanowires self-aligned on pre-patterned rippled substrate are presented for the first time as an active SERS substrate. Anisotropic SERS response in such arrays is attributed to different field enhancement along and across the ripples. Strong plasmonic coupling in elongated nanoparticles chain results in significantly higher SERS intensity then spherical nanoparticles/nanowires and non-ordered nanoparticles. Higher SERS intensity across the nanowires array in comparison to along the array (bulk silver) confirms electromagnetic field enhancement (hot-junction) is responsible for SERS phenomenon. Self-assembly of cobalt nanoparticle on ripple pattern substrate is also reported. Due to less adatom mobility and higher sticking cobalt self-assembly is possible only at much higher temperature. A strong uniaxial magnetic anisotropy was observed not observed for non ordered cobalt particles.

Doctor of Philosophy / Department of Chemistry / Christine Aikens / Thiolate-protected noble metal nanoparticles (~2 nm size) are efficient solar photon harvesters, as they favorably absorb within the visible region. Clear mechanistic insights regarding the photo-physics of the excited state dynamics in thiolate-protected noble metal nanoclusters are important for future photocatalytic, light harvesting and photoluminescence applications. Herein, the core and higher excited states lying in the visible range are investigated using the time-dependent density functional theory method for different thiolate-protected nanoclusters. Nonadiabatic molecular dynamics simulations are performed using the fewest switches surface hopping approach with a time-dependent Kohn-Sham (FSSH-TDKS) description of the electronic states with decoherence corrections to study the electronic relaxation dynamics. Calculations on the [Au₂₅ (SH)₁₈]⁻¹ nanocluster showed that relaxations between core excited states occur on a short time scale (2-18 ps). No semiring or other states were observed at an energy lower than the core-based S₁ state, which suggested that the experimentally observed picosecond time constants could be core-to-core transitions rather than core-to-semiring transitions. Electronic relaxation dynamics on [Au₂₅ (SH)₁₈]⁻¹ with different R ligands (R = CH₃, C₂H₅, C₃H₇, MPA) [MPA = mercaptopropanoic acid] showed that all ligand clusters including the simplest SH model follow a similar trend in decay within the core states. In the presence of higher excited states, R= H, CH₃, C₂H₅, C₃H₇ demonstrated similar relaxations trends, whereas R=MPA showed a different relaxation of core states due to a smaller LUMO+1-LUMO+2 gap. Overall, the S₁ state gave the slowest decay in all ligated clusters. An examination of separate electron and hole relaxations in the [Au₂₅ (SCH₃)₁₈]⁻¹ nanocluster showed how the independent electron and hole relaxations contribute to its overall relaxation dynamics. Relaxation dynamics in the Au₁₈(SH)₁₄ nanocluster revealed that the S₁ state has the slowest decay, which is a semiring to core charge transfer state. Hole relaxations are faster than electron relaxations in the Au₁₈(SH)₁₄ cluster due its closely packed HOMOs. The dynamics in the Au₃₈(SH)₂₄ nanocluster predicted that the slowest decay, the decay of S₁₁ or the combined S₁₁-S₁₂, S₁-S₂-S₄-S₇ and S₄-S₅-S₉-S₁₀ decay, involves intracore relaxations. The phonon spectral densities and vibrational frequencies suggested that the low frequency (25 cm⁻¹) coherent phonon emission reported experimentally could be the bending of the bi-icosahedral Au₂₃ core or the “fan blade twisting” mode of two icosahedral units. Relaxation dynamics of the silver nanoparticle [Ag₂₅ (SR)₁₈]⁻¹ showed that both [Ag₂₅(SH)₁₈]⁻¹ and [Au₂₅ (SH)₁₈]⁻¹ follow a common decay trend within the core states and the higher excited states.

Magister Scientiae - MSc / With an increase in the amount of harmful carbon emissions in the atmosphere as well as a decrease in the availability of fossil fuels, there is a relatively high demand for alternate energy devices. Solar cells have become an alternative option in aid of leading the way for clean energy; however these devices are relatively expensive and have an efficiency that is relatively low in comparison to that of fossil fuelled energy. As a result the cost of the solar cell needs to be reduced by reducing the amount of silicon used in order to compete with fossil fuelled devices; however this decrease would lead to a decrease in efficiency. In recent years silver nanoparticles have been extensively researched as a result of its extraordinary optical, electrical, catalytic, magnetic and antibacterial properties. As a result of these properties, the nanoparticles may be applied to many research areas such as photovoltaics, catalysis and medical fields. The optical properties of silver nanoparticles may thus be exploited in order to increase absorption and in turn the efficiency of the solar cell devices. This study focuses on the optimization of the polyol synthesis to possibly obtain uniformly dispersed silver nanoparticles. The silver nanoparticles would then be incorporated onto amorphous silicon thin films, deposited by hot wire chemical vapour deposition, by spraying a suspension of the silver nanoparticles onto the thin films. The silver nanoparticles were viii characterized by Ultra Violet Visible Spectroscopy (UV-VIS), High Resolution Transmission Electron Microscopy, X-ray Diffraction, and Thermogravimetric Analysis. The thin films with the incorporated silver nanoparticles were characterized by UV-VIS, and High Resolution Scanning Electron Microscopy. It was shown that silver nanoparticles with various morphologies were produced by the polyol synthesis and may be used to enhance light trapping of thin film photovoltaic devices.

Magister Scientiae - MSc (Chemistry) / Pulmonary Tuberculosis (TB) a disease second to HIV/AIDS is a global health problem that arises in two states; as an active state and as a latent state. Diagnosis of active TB is tedious and requires expensive procedures since there is no recognizable method for the sole detection of active TB. The current diagnosis consists of chest X-rays and multiple sputum cultures used for acid-fast bacilli detection. The TB diagnosis of children is particularly difficult which further complicates the diagnosis. Thus, rapid identification of this pathogen is important for the treatment and control of this infection to allow effective and timely therapy. In an effort to solve this issue, this study reports the development of immunosensors constructed with electroactive layers of amino groups functionalized graphene oxide (GO) doped respectively with green synthesized zinc oxide (ZnO NPs) nanoparticles and silver (Ag NPs) nanoparticles on glassy carbon electrodes. The surface morphology of GO, ZnO NPs, Ag NPs and their composites was revealed by employing High-Resolution Transmission Electron Microscopy (HR-TEM) and High-Resolution Scanning Electron Microscopy (HR-SEM) while the composition and structure of these materials were studied using Fourier Transform Infra-Red Spectroscopy (FTIR). The resultant graphene oxide-metallic composites were covalently attached with CFP-10 and/or ESAT-6 antibodies to achieve the electrochemical detection. The immunosensor was then used for the impedimetric and amperometric detection of anti-CFP-10 and/or anti-ESAT-6 antigens in standard solutions.

Percebe-se um interesse da indústria de fabricação de tintas na utilização de nanopartículas de prata devido às suas propriedades antimicrobianas. Neste trabalho, objetivou-se sintetizar e caracterizar soluções coloidais de nanopartículas de prata para ser um potencial aditivo antimicrobiano em tintas acrílicas à base d’água. No processo experimental, as nanopartículas de prata foram preparadas pela redução de íons de prata por boroidreto de sódio e estabilizada, utilizando citrato trissódico dihidrado. As caraterizações das nanopartículas de prata foram realizadas por espectroscopia de UV-Visível, microscopia eletrônica de transmissão e antibiograma contra bactérias Gram-positivas e Gram-negativas. Os espectros de UV-vis foram muito similares para as NPs Ag 18 ppm e para as NPs Ag 1000 ppm com os espectros de absorção na região de 400nm, que indica a presença de NPs Ag com forma esférica. Pela microscopia eletrônica de transmissão confirmou-se a presença das NPs Ag na forma esférica e observou-se a diferença de tamanho de partículas, sendo que para as NPs Ag a média foi de 7,32 nm e para NPs Ag 1000 ppm foi de 15,2 nm. O antibiograma demonstrou que as NPs Ag 18 ppm e de 1000 ppm apresentam atividade antibacteriana contra a bactéria Gram-negativa Escherichia coli e contra a bactéria Gram-positiva Staphylococcus aureus. No filme de tinta aplicado, avaliou-se a diferença de cor da tinta branca após a adição das NPs Ag, utilizando um espectrofotômetro e a perda de brilho após o ensaio de intemperismo acelerado sob radiação UV-B. Foi verificado que as NPs Ag não têm efeito sobre a perda de brilho do filme de tinta, porém induzem ao amarelamento do mesmo. Os resultados foram positivos para o ensaio de resistência a bactérias conforme a norma JIS Z 2801:2000 somente para as amostras de tinta acrílica à base d’água e verniz acrílico à base d’água com 100 ppm de NPs Ag. Para as amostras de tintas e vernizes com 3,6 ppm e 30 ppm de NPs Ag não houve efeito inibitório. Para o ensaio de resistência a fungos, segundo a norma ABNT NBR 14941, as tintas não apresentaram efeito inibitório satisfatório. / There is a particular interest of the paint manufacturing industry by using silver nanoparticles due its antimicrobial properties. This study has as objective to synthesize and characterize silver nanoparticles colloidal solutions as a potential antimicrobial additive in water-based acrylic paints. In the experimental process, the silver nanoparticles were prepared by reduction the silver ions by sodium borohydride and used trisodium citrate dihydrate as stabilizing agent. The characterizations of the silver nanoparticles were realized by spectroscopy in the infrared region, transmission electronic microscopy and Gram positive and Gram negative antibiograms. The UV-vis results were similar for the NPs Ag 18 ppm and NPs Ag 1000 ppm samples with the absorption spectra in the range of 400nm, which indicates the presence of de NPs Ag in a spherical format. By the transmission electron microscopy it was noted the presence of NPs Ag in a spherical format and differences in the particles sizes for NPs Ag (media of 7.32 nm) and for NPs Ag 1000 ppm (media of 15.2 nm) samples. The antibiogram test demonstrates that the 18 ppm and the 1000 ppm NPs Ag showed antibacterial activity against the Gram negative bacterium Escherichia coli and against the Gram positive bacteria Staphylococcus aureus. In the paint film, it was avaluated the difference of the white color after the incorporation of the NPs Ag using a spectrophotometer and the brightness lost after the UV-B accelerated weathering testing. It was noted that the NPs Ag had no effect in the brightness lost of the paint film; however inducing to the yellowing of the same. The results were positive for the bacterial resistances according to JIS Z 2801:2000 only for the water-based acrylic paints and varnish containing 100 ppm of NPs Ag. For the samples with 3,6 ppm and 30ppm it was not noted an inhibitory effect. Finally, for the fungal resistance according to ABNT NBR 14941 the paints do not showed satisfactory inhibitory effect.

Magister Scientiae - MSc (Chemistry) / Nanoscience and nanotechnology are known to be interdisciplinary, crossing and combining various fields and disciplines in pursuit of desirable outcomes. This has brought about applications of nanoscience and nanotechnology in multitudes of industries, spanning from the health, pharmaceutical to industrial industry. Within the health industry, the medical field has seen much advancement through nanoscience and nanotechnology. The importance of finding cures to diseases is top priorities within the medical field, along with advancements in understanding and diagnosing diseases. Due to these outcomes, we see the emergence of imaging techniques playing a crucial role. The work covered in this thesis looks at a prospective luminescent agent applicable in the medical field for bio-imaging, but also at a possible phthalocyanine sensitizer for treatment of cancer through photodynamic therapy. Another area where nanoscience and nanotechnology are found is in industry, where nanoparticles are utilised as catalysts in many synthetic reactions. Highly desirable catalysts in industry are those involved in oxidative reactions where we explore a metal nanoparticle catalyst within this work.