X-ray absorption spectroscopy and microscopy of molecular materials: from fundamentals to applications

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My research group studies basic questions in the X-ray absorption spectroscopy (XAS) of molecules and uses these insights to study complex molecular materials by X-ray spectromicroscopy. The shape of features in the XAS of molecules are complex and have largely escaped analytical scrutiny. Various broadening mechanisms are implicated as the origin of these shapes (width, asymmetry, etc). However, without an effective model to interpret these shapes, this aspect of molecular XAS is often ignored. The combination of improved XAS experiments at the Canadian Light Source (CLS), new theoretical ideas and high performance computing allows us now to address these challenging questions. This program will explain line shapes and broadening in molecular XAS and use these phenomena to examine structure and order in molecular nanomaterials. XAS line shape analysis will also allow us to study aggregation in organic electronic devices and the structural origin of unusual ultrastable molecular glasses. Through the use of complementary synchrotron methods, this program will also use molecular XAS in an X-ray Microscope (that is, X-ray spectromicroscopy) to study how ordered molecular nanomaterials are formed. Study of model systems (vapour deposition of n-alkanes on high symmetry surfaces) will be used to develop general insights into thin film growth. In turn, these insights will be used to develop general methods to pattern and define molecular orientation at the nanoscale. Such technologies can be used to create functional materials that rely on molecular order, such as organic electronic devices, metamaterials, waveguides and liquid crystal-based devices. Fundamental understandings of molecular XAS are essential for these efforts. This research program extends both XAS and X-ray spectromicroscopy in the study of structure and order in molecular materials. It will provide improved understandings of ultrastable molecular glasses and new methods to make and pattern oriented organic nanomaterials. Much of this work will be performed at the Canadian Light Source (CLS; Saskatoon, SK) and is tied closely to instrumentation and technology developments on the CLS soft X-ray spectromicroscopy beamline.