Materials and synchrotron radiation

我们建议在两个密切相关的方面进行研究：(1)功能纳米材料的基本性质及其在能源、环境、药物传递和金属-生物材料界面方面的应用；(2)基于同步加速器的先进光子技术的开发和应用，特别是高能分辨率电子能谱、高能分辨率x射线（吸收和发射）能谱和显微镜在追踪功能纳米材料和复合材料电子行为方面的应用；它们在设计的功能中所期望的属性和性能。在(1)中，我们将研究一系列具有不同组成、形态、结构和尺寸的纳米结构，涉及两种技术上最相关的元素，硅和碳，以及许多金属氧化物半导体，包括氧化钛、氧化锌和氧化锡，以及纳米金属体系和纳米碳复合材料（例如碳纳米管和石墨烯上的铂纳米颗粒）。我们将继续开发方法来控制纳米材料的合成与所需的成分，尺寸，形态，晶体结构和x射线光谱表征（吸收和光电子）使用可调的x射线源（同步加速器）。在(2)中，我们在过去十年中开发了许多强大的技术，当时加拿大光源（CLS）可供进一步深入研究和开发。作为加拿大光源的SGM （250 -2 keV）、PGM （10 - 250 eV）和SXRMB （1.8-10 keV）光束线的beam team Leader，我领导的这些发展（例如，能量和时间域的x射线激发光学发光可以跟踪不同形貌、尺寸和缺陷分布的纳米结构中的能量和电荷转移动力学）大大增强了推进上述计划(1)的能力。我们将继续完善这些能力-重要领域：(a)最近在CLS的SXRMB光束线上投入使用的最先进的硬x射线光电子能谱站（高达10 keV的x射线能量，具有出色的灵敏度和能量分辨率）将提供前所未有的能力来研究底层和埋藏界面；(b)最先进的软x射线微探针（与环境和生物材料相关的元素的形态，如Ca， S， P， Cl和K，以及催化剂，如Rh， Pd和Ag）正在进行中；(c)在CLS的SGM光束线上安装最先进的光学条纹相机（所有同步加速器中第一个），以研究纳米结构将x射线转化为可见光的动力学，从而揭示系统的电子结构；(d) CLS的SGM和PGM正在升级为椭圆偏振波动器和KB反射镜，以提供偏振可调性和微光束能力，进一步增强CLS已经高产的设施；(e)基于MiniXS设计的最先进的x射线发射分析仪，用于Ce L3和Tb L3边缘的高分辨率x射线荧光。该分析仪使用罗兰圆上的Ge（440）晶体与像素阵列探测器（例如Pilatus 100K PAD）相结合，在~ 4500 eV下提供~ 0.8 eV的分辨率，用于x射线发射（RIXS和rx）研究。这项研究不仅可以为我的研究增强材料（性能、性能等）的协同性和同步加速器分析能力，还可以为CLS用户社区提供前所未有的技术。

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.