Colloquium Series: Luisa Whittaker-Brooks, University of Utah

Insights into the electronic structure of π- and π-d conjugated organic systems via diffraction and soft X-ray spectroscopy

Abstract
π- and π-d conjugated organic systems while highly desirable for a host of applications, present several challenges that remain unresolved, including the ability to control the assembly of the organic and metal-organic components and interfaces at the molecular level (orientation and mode of attachment), matching of phonon band structure in metals with discrete vibrations within the molecule, and tuning energetic offsets for effective charge and spin transfer. Each of these parameters ultimately govern charge transport, the preservation of coherence, and energy transfer. Therefore, there is a need for a concerted effort to develop synthetic and characterization protocols that would allow for the investigation of the morphology and electronic properties of π- and π-d conjugated organic systems as a function of prospective self-assembly motifs. Herein, we provide fundamental insights into different self-assembly protocols that can be used to fabricate well-defined π- and π-d conjugated organic systems. As part of our efforts, we developed a new analytical approach where we can correlate the morphological orientation of thin film materials to various fabrication methods. In this talk, we will discuss how we can use GIWAXS, NEXAFS, and EPR spectroscopy to correlate changes in the electronic structure as a function of the morphology and defect states in π- and π-d conjugated organic systems.

Research Interests
The Whittaker group aims to address important challenges related to the understanding of the relationships among the composition, structure, electronic structure, and properties of inorganic and organic nanomaterials, as well as their composites. Our efforts are focused on three different directions in the areas of materials chemistry and nanotechnology, i.e., synthetic inorganic-organic chemistry, spectroscopy, and nanofabrication of functional devices.

Specifically, our group is driven by two of the greatest challenges of our time –sustainable energy and low cost electronics for daily use applications. We plan to embark in these new endeavors by synthesizing and elucidating the functional properties of well-defined and high-quality materials for applications in photovoltaics, thermoelectrics, batteries, spintronics, and electronics. We are also interested in testing new hybrid concepts in terms of integrating several technologies that can simultaneously perform multiple tasks. For example, we envision fabricating a multimodal energy device that can scavenge different kinds of energies for driving micro/nanosystems based on the functionality of our materials.

As far as training is concerned, members of our group will become proficient in a variety of techniques and will build-up top-notch expertise in inorganic-organic synthesis at ambient and high temperature conditions, morphological and crystal structure characterization (STEM, TEM, EELS, SEM, etc.), in-house spectroscopy characterization (UV-VIS, PL, IR), and device fabrication (e-beam and photolithography).

To assist in understanding the electronic, magnetic and structural modifications of ensemble materials, members of our group are expected to acquire strong proficiency in different Synchrotron techniques such as, grazing incidence X-ray diffraction (GIXD), near-edge extended X-ray absorption fine (NEXAFS) spectroscopy, and X-ray absorption fine structure (XAFS) spectroscopy. Synchrotron studies will be performed at the Cornell High Energy Synchrotron Source (CHESS) and at the National Synchrotron Light Source at Brookhaven National Laboratory.