CAREER: Morphology Control Through a Mechanistic Understanding of Structural Evolution in Organic Semiconductor Mixtures

该奖项旨在以前所未有的细节研究聚合物太阳能电池的活性层形态，以发展对结构形成过程的基本理解。 能量过滤透射电子显微镜将使元素映射在纳米长度尺度，而掠入射X射线散射将提供形态的统计措施。 这些互补技术的结合使得非平衡结构演化的关键材料参数的识别成为可能。 据推测，聚合物半导体/富勒烯的混合物可以被描述为聚合物溶液，因此，在浓溶液中的共轭聚合物的结晶动力学将作为模型实验进行研究。 从结构数据和器件数据的组合中获得的见解将导致与聚合物太阳能电池相关的结构-功能关系。 此外，将探索促进各向异性晶体生长和控制成核的方法作为控制形态的策略。 关于形态学演化的基本知识和广泛适用的介观结构控制策略的结合将使高性能器件的开发变得容易，从而实现聚合物太阳能电池中的新型材料。非技术概要：塑料或聚合物在社会中无处不在。 这是聚合物许多有趣特性的结果。 这项工作的目的是利用其中的一些特性：吸收光，传导电荷，并在纳米长度尺度上自发形成内部结构的能力，或人类头发宽度的1/10，000。 这些特性的组合和优化将使太阳光转化为电力和聚合物基太阳能电池的制造成为可能。 实现所提出的工作的战略是集中在发展的基本理解的聚合物的性质，支配的结构形成过程和有序现象。 综合本科研究和教育活动的建议，以提高保留本科生，并鼓励追求更高的学位。 重点将放在代表性不足的群体，以提高本科生和研究生人口的多样性。 这包括与宾夕法尼亚州立大学的卫星校区开展新的互动，这些校区在某些情况下缺乏学士后学位，但拥有多样化的学生群体，以突出本科生的研究机会。

TECHNICAL SUMMARY:This award aims to examine the active-layer morphology of polymer solar cells in unprecedented detail to develop a basic understanding of the structure formation process. Energy-filtered transmission electron microscopy will enable elemental mapping at nanometer length scales, while grazing-incidence X-ray scattering will provide statistical measures of the morphology. The combination of these complementary techniques makes the identification of the critical material parameters governing non-equilibrium structural evolution possible. It is hypothesized that polymer semiconductor/fullerene mixtures can be described as polymer solutions; thus, the crystallization kinetics of conjugated polymers in concentrated solutions will be studied as model experiments. Insights from the combination of structural data and device data will lead to structure-function relationships relevant to polymer solar cells. Furthermore, methodologies to promote anisotropic crystal growth and control nucleation will be explored as strategies to control the morphology. The combination of basic knowledge regarding the morphological evolution and widely-applicable strategies for mesostructure control will enable the development of high-performance devices by easing the implementation of novel materials in polymer solar cells.NON-TECHNICAL SUMMARY:Plastics, or polymers, are ubiquitous in society. This is a result of the many intriguing properties of polymers. The proposed work aims to take advantage of some of these properties: the ability to absorb light, conduct charges, and spontaneously form an internal structure at nanometer length scales, or about 1/10,000 the width of a human hair. The combination and optimization of these properties will enable sunlight to electricity conversion and the fabrication of polymer-based solar cells. The strategy for achieving the proposed work is centered on developing a basic understanding of the polymer properties which govern the structure-formation process and ordering phenomena. Integrated undergraduate research and educational activities are proposed to improve retention of undergraduate students and encourage the pursuit of advanced degrees. An emphasis will be placed on underrepresented groups to improve diversity in both undergraduate and graduate student populations. This includes developing new interactions with Penn State satellite campuses, which in some cases lack post-bachelor degrees but boast diverse student populations, in an effort to highlight undergraduate research opportunities.