Optical Excitations and Applications in Novel Organic Macromolecular Aggregates

技术概述在创造用于能量收集和非线性光学器件的新材料的过程中，重要的一步是理解基于尺寸、几何形状（环状、二维）和分子内相互作用的结构-功能关系。该提案旨在开发新型有机多功能材料，并使用超快相干光谱来探测这些材料中的能量迁移，非线性光学和量子干涉现象。PI将对几种新型聚合系统进行研究。具体而言，使用飞秒光谱方法的组合，如飞秒时间分辨荧光上转换，瞬态吸收，瞬态光栅，三脉冲光子回波峰移实验与稳态光谱的补充，我们将深入研究各种新的大分子聚集结构。这些结构包括对称性破缺的树枝状大分子、新的二维大分子结构、巨大的环状大分子噻吩聚集体以及一种新型的卟啉聚集体。 PI将根据最近的理论方法进行广泛的建模，描述激子迁移，自陷和聚集系统之间的激发能量转移的细节。非技术性总结这项建议的广泛影响是针对PI的科学教育活动，这些活动成功地鼓励了不同背景的年轻科学家以及妇女的参与。PI将继续将年轻科学家带入材料科学领域，并通过参与夏季丰富和导师计划来激发科学事业，作为校园和国家组织的一部分。 继续与安阿伯和底特律公立高中的互动将在PI实验室的夏季研究机会进行。

TECHNICAL SUMMARYAn 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 SUMMARYThe 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.