Materials and synchrotron radiation

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We propose to conduct research in two intimately related fronts: (1) functional nanomaterials, fundamental properties and applications in energy, environment, drug delivery and metal- biomaterial interface and (2) development and application of synchrotron based advanced photon techniques, especially high energy resolution electron spectroscopy, high energy resolution X-ray (absorption and emission) spectroscopy, and microscopy in tracking the electronic behaviour of functional nanomaterials and composites, and as importantly, their desired properties and performance in a designed functionality. In (1), we will study a series of nanostructures with different composition, morphology, structure and size, involving two most technologically relevant elements, silicon and carbon, and many metal oxide semiconductors including titanium oxide, zinc oxide and tin oxide as well as nanometallic system and nanocarbon composites (e.g. Pt nanoparticles supported on carbon nanotube and graphene). We will continue to develop methodologies for controlled synthesis of nanomaterials with desired composition, size, morphology, crystal structure and in X-ray spectroscopy characterization (absorption and photoelectron) using a tunable X-ray source (synchrotron). In (2), we have developed a number of powerful techniques over the last ten years when the Canadian Light Source (CLS) became available for furthering in-depth investigation and development. These developments (e.g. X-ray excited optical luminescence in both the energy and time domain can track energy and charge transfer dynamics in nanostructures of different morphology, size and defect distribution), which I led as a Beam-team Leader of the SGM (250 -2 keV), PGM (10 – 250 eV) and SXRMB (1.8-10 keV) beamline at the Canadian Light Source, has greatly enhanced the capabilities in advancing program (1) described above. We will continue to perfect these capabilities – significant areas: (a) a state-of-the-art hard X-ray photoelectron spectroscopy station (up to 10 keV X-ray energy with excellent sensitivity and energy resolution) recently commissioned at the SXRMB beamline of the CLS will deliver unprecedented capabilities to investigate the underlayer and buried interface; (b) a state-of-the-art soft X-ray microprobe (speciation of elements relevant to environment and biomaterials, e.g. Ca, S, P, Cl and K, and catalysts, e.g. Rh, Pd and Ag) is under commission; (c) a state-of-the-art optical streak camera on the SGM beamline at CLS (first in all synchrotrons) to study the dynamics in the conversion of X-ray into visible light by nanostructures, which in turn reveals the electronic structure of the system; (d) both SGM and PGM at CLS are being upgraded with elliptically polarized undulators and KB mirrors to provide polarization tunability and microbeam capabilities, further enhancing the already highly productive facilities at the CLS; and (e) a state-of-the-art X-ray emission analyser based on the MiniXS design for high resolution X-ray fluorescence from the Ce L3 and Tb L3 edge. The analyzer using Ge(440) crystals on a Rowland circle combined with a pixel array detector (e.g. the Pilatus 100K PAD) provides a resolution of ~ 0.8 eV at ~ 4500 eV for X-ray emission (RIXS and RXES) studies. The proposed research will not only enhance the synergy of materials (properties, performance, etc.) and synchrotron analysis capabilities for my research but also provides unprecedented techniques to the CLS users’ community.