Excitonic Coupling in Molecular and Polymeric Aggregates: Beyond Conventional J- and H-aggregation

分子和聚合物聚集体中的激子耦合：超越传统的 J 和 H 聚集

• 批准号: 1505437
• 负责人: Francis Spano
• 金额: $ 36万
• 依托单位: Temple University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1505437&HistoricalAwards=false
• 关键词: Excitonic; Coupling; Molecular; Polymeric; Aggregates

NONTECHNICAL SUMMARYOrganic molecules and polymers continue to receive attention as semiconducting materials in a wide array of practical applications, including paper electronics, solid-state lighting, solar cells and scaffolds for tissue growth. Most devices benefit from rapid energy transport, which is dictated by how fast an electronic excitation on one molecule can be transferred to a more distant molecule. However, despite the more than five decades of intensive experimental and theoretical research, there are still many questions regarding the nature of the electronic excitations in organic molecular aggregates, thin films and crystals. The main objective of the proposed research is to develop a theory of electronic coupling between molecules which takes into account the organization of molecules relative to each other. This theory will provide information about the rate of energy transfer and will reveal important information about the properties of the electronic excitations, information that can be used to design more efficient devices. The PI's group will also explore the use of optical microcavities for controlling material properties. Microcavities consist of two mirrors separated by a very short distance of the order of one millionth of a meter. The interaction between light and matter is greatly amplified for materials inserted between such mirrors. The proposed research will benefit from collaborations with the experimental groups at the University of Massachusetts and the University of Montreal. The broader impact of the proposed research will be in an enhanced understanding of the photophysical and transport properties of a technologically important class of materials. The commercial impact of organic electronic devices is expected to dramatically increase over the next decade through products like flexible displays, electronic labels, solid-state lighting and solar cells. The wide array of photophysical and transport behaviors afforded by molecular aggregates studied in this proposal could provide the basis for novel design paradigms for efficient solar absorbers and light emitting materials.TECHNICAL SUMMARYThe main goal of the proposed research is to develop a theory for the photophysical response of molecular aggregates which accounts for the simultaneous presence of long-range Coulombic interactions and short-range charge-transfer (CT) interactions between the constituent molecules. The theory will consider the electronic coupling, the electronic-nuclear coupling, and diagonal and off-diagonal disorder on equal footing and will extend the conventional J- and H-aggregate model of Kasha to systems such as molecular pi-stacks, in which the very close proximity between neighboring molecules allows for significant overlap between molecular orbitals. Investigations are planned to understand the photophysical and transport properties of different aggregate types and how such aggregates evolve into conventional H- and J-aggregates as the adiabatic CT exciton is tuned away from the parent Frenkel exciton. Studies will also be undertaken to determine how aggregate properties are altered by immersion into a tuned optical microcavity. The analyses will be based on Holstein-like Hamiltonians represented in a one- and two-particle basis set. Fundamental excitations and their spectral signatures will be evaluated using numerical matrix techniques. Specific applications will be made to rylene pi-stacks which have been studied as dye pigments and electron-transporting materials, as well as poly(3-hexylthiophene) pi-stacks which make excellent exciton transporting materials in photovoltaic devices. The proposed research will benefit from collaborations with the experimental groups at the University of Massachusetts and the University of Montreal. The broader impact of the proposed research will be in an enhanced understanding of the photophysical and transport properties of a technologically important class of materials. The commercial impact of organic electronic devices is expected to dramatically increase over the next decade through products like flexible displays, electronic labels, solid-state lighting and solar cells. The wide array of photophysical and transport behaviors afforded by molecular aggregates studied in this proposal could provide the basis for novel design paradigms for efficient solar absorbers and light emitting materials.

非技术性摘要分子和聚合物在各种各样的实际应用中继续受到关注，包括纸电子，固态照明，太阳能电池和脚手架以用于组织生长。大多数设备受益于快速能源传输，这取决于可以将一个分子上电子激发传递到更遥远的分子上的速度。然而，尽管有五十多年的深入实验和理论研究，但在有机分子骨料，薄膜和晶体中电子激发的性质仍然存在许多问题。拟议的研究的主要目的是发展分子之间电子耦合的理论，该理论考虑了分子相对于彼此的组织。该理论将提供有关能量传递速率的信息，并将揭示有关电子激发的特性，可用于设计更有效设备的信息。 PI的组还将探索使用光学微腔来控制材料特性的使用。 微腔由两个镜子组成，分别是一百万米的非常短的距离。光与物质之间的相互作用大大放大了此类镜子之间插入的材料。拟议的研究将受益于马萨诸塞大学和蒙特利尔大学的实验小组的合作。拟议研究的更广泛影响将是对技术重要材料类别的光物理和运输特性的增强理解。预计有机电子设备的商业影响将在未来十年中通过柔性显示器，电子标签，固态照明和太阳能电池等产品急剧增加。 The wide array of photophysical and transport behaviors afforded by molecular aggregates studied in this proposal could provide the basis for novel design paradigms for efficient solar absorbers and light emitting materials.TECHNICAL SUMMARYThe main goal of the proposed research is to develop a theory for the photophysical response of molecular aggregates which accounts for the simultaneous presence of long-range Coulombic interactions and short-range charge-transfer （CT）组成分子之间的相互作用。该理论将在平等的基础上考虑电子耦合，电子核耦合以及对角线和偏离障碍，并将Kasha的常规J和H凝集模型扩展到分子PI-stack等系统，例如，邻近邻近分子之间的非常紧密的近距离可以使大量的分子之间具有重要的覆盖物或分子之间的重要性。 计划进行研究，以了解不同骨料类型的光体物理和转运特性，以及随着绝热CT激子从亲本Frenkel Ixpiton的调整，这种聚集体如何演变为常规的H-和J聚集。还将进行研究，以确定如何通过浸入调节的光学微腔来改变骨料特性。这些分析将基于以单粒子和两粒子为代表的荷斯坦样哈密顿人。基本激发及​​其光谱特征将使用数值矩阵技术进行评估。将对已研究为染料色素和电子传输材料以及聚（3-己基噻吩）PI-stacks的Rylene Pi-stacks进行特定应用，这些PI堆在光伏设备中可以很好地运输激子运输材料。拟议的研究将受益于马萨诸塞大学和蒙特利尔大学的实验小组的合作。拟议研究的更广泛影响将是对技术重要材料类别的光物理和运输特性的增强理解。预计有机电子设备的商业影响将在未来十年中通过柔性显示器，电子标签，固态照明和太阳能电池等产品急剧增加。该提案中研究的分子聚集体提供的各种光物理和运输行为可以为有效的太阳能吸收剂和光发射材料提供新的设计范式的基础。