Electronic Structure of Pristine and Highly Doped Conducting Polymers

9802300 Kertesz这是一个理论研究补助金，由材料研究和化学部门共同资助。 研究集中在导电共轭聚合物的两个基本方面。 首先，将制定理论指导方针，以回答这个问题：是否有一个最小的带隙在这个家庭的新材料？尽管全世界都在努力在共轭聚合物中获得0.5eV或更小的带隙，但很少有带隙明显低于1eV的例子。 虽然在导电聚合物中获得小的带隙可能会导致有趣的应用，但这个问题本身就提出了一个具有广泛兴趣的深刻挑战。 只有通过系统地确定影响电活性聚合物的结构和电子性质的因素，包括杂原子和侧基的贡献，拓扑结构（阶梯，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。 这就引出了第二个方面。 众所周知，链间相互作用的影响在理论上很难处理。 在这项研究中，这个问题的一个基本方面将被攻击的一种新的方式：实验振动光谱将被用来获得interring扭转的值，这将是太敏感的纯理论计算，但不能从实验中获得。 IR和拉曼光谱的精确建模，包括强度，作为环间耦合的函数，将允许确定关键的结构数据，如环间键距和扭转。 目前，导电聚合物的结构、振动光谱和电子结构的理论建模还缺乏统一的方法。 该项目将为各种非局部密度泛函及其在有机聚合物材料中的应用提供一个多功能的测试平台。 应用包括共轭聚合物的主要类型。 这是一个理论研究补助金，由材料研究和化学部门共同资助。 研究集中在导电共轭聚合物的两个基本方面。 首先，将制定理论指导方针，以回答这个问题：是否有一个最小的带隙在这个家庭的新材料？ 此外，众所周知，链间相互作用的影响在理论上很难处理。 因此，第二，在这项研究中，这个问题的一个基本方面将被攻击在一个新的方式：实验振动光谱将被用来获得的值interring扭转太敏感，纯理论计算，但不能从实验中获得。 这项研究的结果将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. ***