Electronic Structure of Pristine and Highly Doped Conducting Polymers

9802300科尔特斯：这是一项理论研究基金，由材料研究和化学系联合资助。这项研究集中在导电共轭聚合物的两个基本方面。首先，将开发理论指南来回答这个问题：在这种新材料家族中是否存在最小带隙？尽管全世界都在努力在共轭聚合物中实现0.5 eV或更低的带隙，但极少数带隙明显低于1 eV的例子存在。虽然在导电聚合物中获得很小的带隙可能会导致有趣的应用，但这个问题本身就是一个具有广泛兴趣的深刻挑战。只有系统地确定影响电活性聚合物结构和电子性质的因素，包括杂原子和侧基的贡献、拓扑(梯形、环等)的影响、共面性和其他构象自由度的影响，才有可能设计出具有所需小带隙的新材料。这导致了第二个方面。众所周知，链间相互作用的影响很难从理论上处理。在这项研究中，这个问题的一个基本方面将以一种新的方式来解决：实验的振动光谱将被用来获得环间扭矩的值，该值太敏感，不能纯粹从理论上计算，但不能从实验中获得。作为环间耦合的函数，对包括强度在内的红外和拉曼光谱进行精确建模，将允许确定关键的结构数据，如环间键长和扭转。目前，导电聚合物的结构、振动光谱和电子结构的理论模拟缺乏统一的方法。该项目将为各种非局域致密官能团及其在有机聚合物材料中的应用提供一个通用的试验场。应用包括主要类型的共轭聚合物。这是一项理论研究基金，由材料研究部和化学系联合资助。这项研究集中在导电共轭聚合物的两个基本方面。首先，将开发理论指南来回答这个问题：在这种新材料家族中是否存在最小带隙？此外，众所周知，链间相互作用的影响很难从理论上处理。因此，第二，在这项研究中，这个问题的一个基本方面将以一种新的方式进行攻击：实验的振动光谱将被用来获得环间扭转值，该值太敏感，不能纯粹从理论上计算，但不能从实验中获得。这项研究的结果应该有助于更好地理解一类重要的材料。***

9802300 Kertesz This is a theoretical research grant which is funded jointly by the Divisions of Materials Research and Chemistry. The research focuses on two fundamental aspects of conducting conjugated polymers. First, theoretical guidelines will be developed in order to answer the question: Is there a minimum bandgap in this family of novel materials? Despite worldwide efforts to attain a bandgap of 0.5eV or less in conjugated polymers, very few examples of bandgaps exist that are significantly below 1 eV. While attaining a small bandgap in a conducting polymer will probably lead to interesting applications, this problem presents a profound challenge in its own right which is of broad interest. The design of new materials with the desired small bandgap will be possible only through systematic determination of the factors influencing the structure and electronic properties of electroactive polymers including the contributions of heteroatoms and side groups, the effects of topology (ladders, rings, etc), the influence of coplanarity and other conformational degrees of freedom. This leads to the second aspect. The effects of interchain interactions are notoriously difficult to treat theoretically. In this research a fundamental aspect of this problem will be attacked in a novel fashion: the experimental vibrational spectra will be used to obtain the value of interring torsion that would be too sensitive to calculate purely theoretically, but cannot be obtained from experiment. Accurate modeling of IR and Raman spectra, including intensities, as a function of interring coupling, will allow the determination of critical structural data, such as interring bond distances and torsion. Currently, there is a lack of a unified approach in the theoretical modeling of the structure, vibrational spectra and electronic structures of conducting polymers. This project will provide a versatile testing ground for the critical evaluation of various non-local densit y functionals and their applications to organic polymeric materials. Applications include the main types of conjugated polymers. %%% This is a theoretical research grant which is funded jointly by the Divisions of Materials Research and Chemistry. The research focuses on two fundamental aspects of conducting conjugated polymers. First, theoretical guidelines will be developed in order to answer the question: Is there a minimum bandgap in this family of novel materials? Also, the effects of interchain interactions are notoriously difficult to treat theoretically. Thus, second, in this research a fundamental aspect of this problem will be attacked in a novel fashion: the experimental vibrational spectra will be used to obtain the value of interring torsion that would be too sensitive to calculate purely theoretically, but cannot be obtained from experiment. The results of this research should lead to a better understanding of an important class of materials. ***