Structure and Dynamics at Organic Semiconductor Interfaces: The Influence of Molecular Electronic Structure

在美国国家科学基金会化学部化学结构、动力学和机制项目的支持下，亚利桑那大学的奥利弗·蒙蒂教授带领一组科学家研究了决定有机半导体界面电荷转移的关键因素。通过选择一类相关但可调谐的有机半导体分子，在具有明确性质的表面上，本研究独特地允许系统控制界面，以提取分子和表面电子结构对界面电荷转移动力学的影响。初步结果表明，容易获得的分子性质，如分子偶极矩和四极矩，以及表面的能带结构，以预测的方式决定了基态和激发态的界面电子结构。研究将确定这些性质如何决定界面上电子激发的命运，并将使揭示有机半导体界面电荷转移的潜在物理学成为可能。所提出的实验的高度控制方法将促进对具有复杂电子结构和丰富薄膜生长特性的扩展pi共轭有机分子界面的电荷转移过程的理解。界面电荷转移通常是许多化学过程中的关键步骤，但它在新型太阳能转换平台和基于有机材料的催化中起着核心作用。因此，拟议的研究计划将加深对化学基本驱动力之一的理解。它的重点是有机电子材料，它将有助于在更广泛的能源科学领域培养研究生和本科生的科学劳动力，这是国家迫切需要的领域。拟议研究的结果也将在概念上融入“太阳能奇才”，这是一个让孩子和他们的父母发现阳光作为能源的潜力的动手科学表演，并与美国化学学会学生会员（SMACS）的当地分会一起开发。“太阳能奇才”预计将前往图森的“太阳能摇滚”音乐节，这是一个为期数天的年度社区音乐节，致力于替代能源发电，并参加图森郊区原住民学校的课后科学项目。

With the support of this award from Chemical Structure, Dynamics and Mechanisms program in the Chemistry Division of the National Science Foundation, Professor Oliver Monti from the University of Arizona leads a team of scientists to investigate the critical factors that determine charge-transfer at interfaces of organic semiconductors. By choosing a class of related yet tunable organic semiconductor molecules on surfaces with well-defined properties, this research uniquely permits systematic control of the interface in order to extract the influence of the molecular and surface electronic structure on interfacial charge-transfer dynamics. Initial results show that easily accessible molecular properties such as the molecular dipole and quadrupole moment, together with the band structure of the surface, dictate in a predictive fashion the interfacial electronic structure both in ground and excited states. Research will establish how these properties determine the fate of electronic excitations at interfaces and will make it possible to unravel the underlying physics of interfacial charge-transfer in organic semiconductors. The highly controlled approach of the proposed experiments will advance understanding of charge-transfer processes to interfaces of extended pi-conjugated organic molecules with complex electronic structure and rich thin film growth properties. While interfacial charge-transfer is a crucial step in many chemical processes in general, it is central in novel solar energy conversion platforms and catalysis based on organic materials. The proposed research program will thus develop a deeper understanding of one of the fundamental driving forces in chemistry. With its focus on organic electronic materials it will aid in developing a scientific workforce both at the graduate and undergraduate level in the broader area of energy sciences, an area of critical national need. Findings from the proposed research will flow conceptually also into "Solar Wizards", a hands-on science show for children and their parents to discover the potential of sunlight as a power source and developed together with the local chapter of the Student Members of ACS (SMACS). "Solar Wizards" is anticipated to travel to "Solar Rock," a yearly multi-day community-based music festival in Tucson dedicated to alternative energy generation, and to after-school science programs in Native Nations schools on the outskirts of Tucson.