8^th World Congress on Spectroscopy and Analytical Techniques September 11-12, 2018 Quality Hotel Globe | Stockholm, Sweden

Martin Ntwaeaborwa is professor of Physics at the University of the Witwatyersrand in South Africa. He obtained his PhD from the University of the Free State in 2006. He has published more than 235 papers in prestigious journals and has given numerous invited talks at local and international conferences

Phosphors have many uses today in applications such as electronic information displays, solid state lighting, solar cells, advertising and theft prevention. By using urea-assisted solution combustion method, we prepared tunable multicolour and white light emitting rare-earths (Pr3+ and Dy3+) doped oxyorthosilicate (R2SiO5) (R = La, Y, Gd) phosphors. We have investigated the photoluminescent properties of LaYSiO5:Dy3+;Pr3+, LaGdSiO5:Dy3+;Pr3+, GdYSiO5:Dy3+;Pr3+ and La2-xGdxSiO5:Dy3+;Pr3+ (x = 0, 0.5, 1.0, 1.5 and 2.0) in powders and thin film forms. The films were ablation deposited onto Si (100) substrates using the pulsed laser deposition technique. Several deposition parameters were varied, including vacuum versus partial pressure of gas (O2 or Ar), type of laser pulse, and substrate temperature. The samples were analyzed using X-ray diffraction, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy and photoluminescnt spectroscopy. The photoluminescent (PL) data were collected in air under excitation by either a 325 nm HeCd laser or a monochromatized xenon lamp. The PL intensities were strongly dependent on the Pr3+ and Dy3+ dopant concentrations, the ratio of La to Gd, deposition condition and post-deposition annealing. Data from the scanning electron microscopy and atomic force microscopy showed that the major influence of the deposition conditions on the PL intensity was through changes in the morphology and topography of the films, which affects light scattering and out-coupling. The colour purity of the bands estimated using CIE coordinates confirmed that our samples were emitting tunable multicolour and white light. The elemental composition analysis indicated that there was a correlation among the EDS, XPS and TOF-SIMS data. The structure, particle morphology, surface chemical composition and electronic states, photoluminescent properties and possible applications of these materials in UV pumped LEDs will be discussed

Oara Neumann has completed her PhD and Postdoctoral study in Applied Physics at Rice University and MS from Weizmann Institute of Science, Israel, and Bucharest University, Romania. She is a research scientist in Naomi Halas group at Rice University. She holds 12 patents and she has published more than 25 papers in reputed journals.

Multifunctional plasmonic nanostructures have enormous potential in the treatment of solid tumors; however, tracking particles with drug cargo and triggering the release of the cargo in mapped tumors is still impossible. To overcome this challenge we have developed an MRI and fluorescent active nanostructure nanomatryoshka. This new nanostructure with IR plasmonic signatures is composed of a 50 nm Au core surrounded by dye molecules and Gd(III)-DOTA chelate doped SiO2 inner-shell and an outer Au shell. The experimental results demonstrates an enhanced T1 relaxation (r1 ~ 24 mM-1 s-1 at 4.7 T) compared to the clinical Gd(III)-DOTA chelating agents (r1 ~ 4 mM-1 s-1). Further, this design preserves the fluorescence signal (65%) after 24 hours of exposure, leading to enahanced fluorescence photostability (23x). This dual-imaging functionality nanosystem increases MRI sensitivity by concentrating Gd(III) ions into the Gd-NMs, reduces the potential toxicity of Gd(III) ions and dye molecules by preventing their release in vivo through the outer Au shell protection, and the terminal gold layer surface can then be functionalized to increase cellular uptake, circulation time, or thermal drug-release properties.

Kenith Meissner received his PhD from the University of Arizona, Optical Sciences Center in the area of ultrafast spectroscopy and semiconductor physics. He then served as a Postdoctoral Appointee at Sandia Naitonal Labs. After spending 7 years in industry developing noninvasive blood gluscose technology, Prof. Meissner returned to academia with positions at Virginia Tech (USA), Texsas A&M University (USA) and Swansea University (UK). His research focuses on biomedical optics and micro-/nano-materials.

Ultrabithorax (Ubx) is a Drosophila melanogaster transcription factor protein the Bondos group discovered has the ability to form ordered materials in vitro. Ubx monomers are produced in E.coli and, following purification, are suspended in a buffer solution and where they do not aggregate in the volume of the solution when refrigerated. When allowed to rest at room temperature, the monomer self assembles at the air/water interface through nucleation, fibril formation and, eventually, film integration. The the self assembled film can then be pulled into a fibre with diameters in the range of 2–50 μm or lifted off as a film with microscale thickness. These materials are highly elastic and maintain physical properties through cycles of drying and re-hydrating. Novel functions can be directly incorporated into Ubx-based materials via gene fusion to produce chimeric polypeptides capable of both self-assembly and the desired chemical reactivity. Unlike most protein-based materials, the gentle conditions under which Ubx self-assembles enable incorporation of active heterologous proteins. This talk will review recent work on the continued development of this unique materials system including mechanical properties enabled by dityrosine bonding between monomers, dynamics of surface film assembly, and advances in Ubxbased

materials production.