An important step in the process of creating new materials for energy harvesting and nonlinear optical devices is in the understanding of the structure-function relationships based on size, geometry (cyclic, 2-dimensional), and intramolecular interactions. This proposal is directed at the development of novel organic multifunctional materials and the use of ultra-fast coherent spectroscopy to probe energy migration, nonlinear optical, and quantum interference phenomena in these materials. The PI will carry out Investigations of several novel aggregated systems will be performed. Specifically, using a combination of femtosecond spectroscopic methods such as femtosecond time-resolved fluorescence upconversion, transient absorption, transient grating, three pulse photon echo peak shift experiments complemented with those of steady state spectroscopy we will deeply investigate a variety of novel macromolecular aggregated architectures. These architectures include dendrimers with broken symmetry, new two-dimensional macromolecular structures, giant cyclic macromolecular thiophene aggregates, as well as a novel porphyrin aggregate. The PI will perform extensive modeling based on recent theoretical approaches describing exciton migration, self-trapping and the details of the excitation energy transfer between aggregated systems.
NON-TECHNICAL SUMMARY The broader impact of this proposal is directed to the PI's science education activities which have been successful in encouraging young scientists of diverse backgrounds as well as the participation of women. The PI will continue to bring young scientists into the field of material science and inspire careers in science with participation in summer enrichment and mentorship programs as part of on campus and national organizations. Continued interactions with Ann Arbor and Detroit public high schools will be carried out in summer research opportunities in the PI's laboratory.
Normal 0 false false false EN-US X-NONE X-NONE There has been a long standing interest in the properties of in organic macromolecules as it relates to many applications involving optical and electronic effects. The PI’s research laboratory has investigated the critical issues in novel macromolecular systems concerning excitation localization and delocalization, disorder and rigidity as well as the role of through space interactions in these systems. We have studied in details the structure and dynamics of optical excitations in novel synthetic organic macromolecules of circular architecture. Ring molecular aggregates are well known to play a crucial role in very efficient natural photosynthetic systems and better understanding of the fundamental properties of the electronic excitations in artificial cyclic systems is of great importance. Support of this grant has helped us to develop a diverse research methodologies focused on the novel optical properties of novel macromolecular systems and obtain new important scientific information regarding the structure of electronic excitations in these systems. The investigations based on an experimental combined approach have allowed a deeper understanding of the fundamental excitations in a variety of new macromolecules systems with particular optical and electronic applications. We started our investigations with giant cyclic macromolecular thiophene and porphyrin aggregates. Our studies later led to other new forms of macromolecular systems like cyclic Ru-Fe and Fe complexes, quinoidal oligothiophenes and platinum acetylide complexes at low temperature as well. The PI has had a number of great collaborations and a large number of students and postdoctoral researchers who have contributed to the success of this project. A strong component of the previous research supported by DMR Polymers at NSF has been the outreach activities which have involved high school students and chemistry teachers, middle school children in lasers and chemistry.
