Molecular-Level Studies of Structure and Photophysics in Conjugated Polymers

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Conjugated polymers represent a class of materials that incorporate the physical attributes of conventional polymers and, simultaneously, electronic and optical properties more often associated with classic inorganic semi-conductors. In terms of science and technology as a whole, these polymers are becoming a mainstream building block for developing new device technologies. This evolutionary progress is based on widespread advancements in materials synthesis, processing and in the science and technology of their applications. At the molecular level they remain highly complex materials with numerous long-standing questions and, given the desire for molecular level engineering, a multitude of newer issues concerning subtle structure/property relationships. Understanding and controlling the three-dimensional organization at the shortest length scales (0.1-10 nm) remains a central issue for defining their potential in real world applications and identifying the ever present limitations. This initiative represents a focused set of research projects that will enhance the fundamental understanding of structure, structural phase behavior in conjugated polymers and, additionally, the impact that structure has on technologically important photophysical properties. A combination of direct diffraction studies, molecular modeling and structure refinement techniques constitute the core of these efforts and these will be used for clarifying issues pertaining to molecular-level structure in the most highly ordered materials. Even in the best cases these conjugated polymers often include multiple conformational sequences along the skeletal backbone. Therefore a proper accounting of these structure/property relationships necessitates a more integrated approach combining other techniques (including photoabsorption, photoluminescence and Raman spectroscopy). Novel polymer processing techniques and extensive use of in situ methodologies will also be exploited. On a broader level this research includes activities which meld multiple techniques and interdisciplinary collaborations in order to congently and comprehensively address central issues of local conjugated polymer structure and its impact on salient photophysics. An important component of this work is portability and accessibility to the science community. This will be accomplished through a set of selected new directions. To the fullest extent possible, all new experimental developments will rely on web-accessible instrumentation interfaces and standardized hierarchal data formats. These attributes will provide ready access to students both at the graduate and undergraduate level. Ultimately the knowledge and techniques developed though the course of this research will provide very basic and accurate answers to questions of structure, its evolution and the direct relationship to photophysics within these diverse materials.