Electronic Structure of Conducting Polymers and Organic Materials

该奖项由材料研究部的材料理论计划和化学部的理论和计算化学计划资助。这个项目的目标是确定策略并进行可靠的计算，以预测有机分子半导体和有机共轭聚合物的基本性质。虽然拟议的工作在很大程度上依赖于第一性原理计算，但计算建模过程中的经验元素被保留和强调。分子间堆积很难从第一性原理进行预测，但堆积直接影响分子间跳跃，这是本项目第一部分要研究的关键参数。分子间堆积对共轭聚合物能带结构的影响是间接的，通常是通过扭转自由度来发挥作用的。在任何一种情况下，直接或间接的关于堆积或扭转的实验信息的集成确保了预测的质量比纯粹的第一原理方法更可靠。对有机分子材料的预测的可靠性通过以二聚体为中心的多尺度方法来确保。二聚体能级分裂可以用非常精确的量子化学方法处理，并将系统地研究一些关键影响因素的影响，包括理论水平、基组和几何效应，这些因素将被用来预测这些材料的电子结构。对于共轭聚合物，该方法包含类似的元素，但建议的工作重点是预测小带隙聚合物。有几种影响带隙的因素，包括连接性，各种几何因素，包括偏离平面性和键局域化，以及其他本质上更具化学性的因素，如杂原子和侧基。计划包括聚合物计算机代码的方法开发，以及跨特定聚合物组的应用，这些聚合物有可能产生非常小的带隙。这项研究有可能通过帮助寻找用于设备应用的新的和更好的功能材料来显著影响实验研究。该项目还包括本科生和研究生。该奖项由材料研究部的材料理论项目和化学部的理论和计算化学项目资助。这个项目的目标是确定策略并进行可靠的计算，以预测有机分子半导体和有机共轭聚合物的基本性质。这项研究有可能极大地影响实验研究，因为它有助于为设备应用寻找新的、功能更好的材料。该项目还涉及本科生和研究生。

This award is funded by the Materials Theory Program in the Division of Materials Research and the Theoretical and Computational Chemistry Program in the Chemistry Division. The objective of this project is to determine strategies and perform reliable calculations for predicting the fundamental properties of organic molecular semiconductors and organic conjugated polymers. While the proposed work relies heavily on first principles calculations, empirical elements in the computational modeling process are retained and emphasized. Intermolecular packing is difficult to predict from first principles, but packing directly effects intermolecular hopping, the key parameter to be studied in the first part of this project. The effect of intermolecular packing on the band structure of conjugated polymers, the subject of the second part of this project, is indirect often exerting its effect through torsional degrees of freedom. In either case, the integration of direct or indirect experimental information on packing or torsion ensures that the quality of the predictions is more reliable, than it would be in a purely first principles approach.The reliability of the predictions for the organic molecular materials is ensured via a multi-scale approach in which dimers play a central role. The dimer level splittings can be treated with very accurate quantum chemical methods, and the effect of a number of key influences will be studied systematically, including level of theory, basis set, and geometrical effects, which will be used to predict the electronic structure of these materials.For conjugated polymers, the approach contains similar elements, but the proposed work focuses on predicting small band-gap polymers. Several effects influence the band-gap, including connectivity, various geometrical factors including deviations from planarity and bond localization, and others that are more chemical in nature such as heteroatoms and side groups. Plans include method development for a polymer computer code, and applications across specific groups of polymers that have the potential of producing very small band-gaps.This research has the potential to significantly influence experimental studies by helping to search for new and better functioning materials for device applications. The project also involves students at the undergraduate and graduate level.%%%This award is funded by the Materials Theory Program in the Division of Materials Research and the Theoretical and Computational Chemistry Program in the Chemistry Division. The objective of this project is to determine strategies and perform reliable calculations for predicting the fundamental properties of organic molecular semiconductors and organic conjugated polymers. This research has the potential to significantly influence experimental studies by helping to search for new and better functioning materials for device applications. The project also involves students at the undergraduate and graduate level.***