Energy and Electron Transport in pi-Stacked Multichromophoric Assemblies: Global Dynamics from the Gas to Condensed Phase

在这个由化学学部大分子、超分子和纳米化学项目资助的项目中，马奎特大学的Rajendra Rathore教授和Scott Reid教授将研究包含堆叠多环芳烃的模型分子组装。这种相互作用是许多分子组合的特征，包括那些在自然界中发现的（例如，DNA），并且理解电子和能量通过这种组合的传输对于开发新的电荷转移材料至关重要，这些材料可以提高光伏器件、分子电子学和纳米技术的应用效率。为了应对这一挑战，我们进行了精心设计的分子组合的合成，并使用基于分子光谱的各种实验策略对这些组合进行了表征，并得到了计算化学的支持。超分子组装利用各种共价和非共价脚手架相互作用。其中，pi堆叠很重要。光伏器件导电层中长距离电荷转移的效率不仅受聚合物主链中的分子内电子传递的影响，还受块体材料中的分子间电子传递的影响，其中π共轭分子的无定形组装通常是随机的。由于类环芳二聚体及其阳离子自由基代表了块状材料中负责电荷传输的最简单的基本单元，因此为分子电子学和纳米技术新兴领域设计和合成现代有机材料需要对精心设计的面状排列分子中的电子和能量传递过程有透彻的了解。该项目解决了关于模型多色系统中能量流和电子转移的基本问题，并开发了利用伴随氧化或电子激发的分子重排等组件的新策略。研究更广泛的影响，这项工作为分子电子学和光伏领域应用的下一代有机材料的设计和合成提供了信息。

In this project funded by the Macromolecular, Supramolecular and Nanochemistry program of the Chemistry Division, Professors Rajendra Rathore and Scott Reid of Marquette University will examine model molecular assemblies that incorporate stacked polycyclic aromatic hydrocarbons. Such interactions are characteristic of many molecular assemblies, including those found in nature (e.g., DNA), and an understanding of the transport of electrons and energy through such assemblies is critical to develop new charge-transfer materials of increased efficiency for applications in photovoltaic devices, molecular electronics, and nanotechnology. To meet this challenge, the synthesis of carefully designed molecular assemblies is carried out, and the assemblies characterized using a variety of experimental strategies based on molecular spectroscopy, supported by computational chemistry. Supramolecular assemblies exploit a variety of covalent and non-covalent scaffolding interactions. Of these, pi-stacking is important. The efficiency of long range charge transfer in the conducting layers of photovoltaic devices is governed not only by the intramolecular electron transport through the backbone of polymers but also by the intermolecular electron transport through bulk material, where the amorphous assembly of pi-conjugated molecules is generally randomized. As cyclophane-like aromatic dimers and their cation radicals represent the simplest fundamental units responsible for charge transport in bulk materials, the design and synthesis of modern organic materials for the emerging area of molecular electronics and nanotechnology demands a thorough understanding of electron and energy-transfer processes in carefully designed cofacially-arrayed molecules. This project addresses fundamental questions concerning the flow of energy and electron transfer in model multichromophoric systems and developes new strategies for exploiting such assemblies as light driven actuators, taking advantage of the molecular rearrangement which accompanies oxidation or electronic excitation. Examining broader impacts, this work informs the design and synthesis of next generation organic materials for applications in the area of molecular electronics and photovoltaics.