CAREER: Micro-structure and Electrical Properties in Thin Films of Semicrystalline Conjugated Polymers

技术：本项目研究半晶共轭聚合物薄膜的微观结构和电学性能，重点是理解结构/输运关系；显微组织包括晶态晶粒、晶界和非晶态材料。该项目将利用聚（噻吩）和聚（噻吩-噻吩），被认为是高性能聚合物半导体。该方法与异质外延和石墨外延相似，可实现长程有序。扫描探针技术、基于同步加速器的高分辨率x射线衍射和原位热退火研究将与微观结构演变的分子动力学（MD）模拟一起进行。将进行耦合的电学和光学表征，以分离微观结构不同方面对材料性能的影响，并通过电荷输运建模来增强实验测量。半导体的态密度将用亚带隙吸收光谱来表征。非技术：该项目涉及材料科学主题领域的基础研究问题，具有很高的技术相关性。该项目为研究生和本科生在跨学科领域的培训提供了独特的机会。除了斯坦福大学的本科生外，PI还将通过工程多样性计划（EDP）积极吸引代表性不足的少数民族学生到他的实验室。这项研究还将被用作一种工具，以“重新激发”参加外展计划的当地高中科学教师。PI计划在当地高中进行演讲，并参加EDP组织的全国推广日。

Technical: This project addresses the micro-structure and electrical properties in thin films of semicrystalline conjugated polymers with emphasis on understanding structure/transport relationships; the micro-structure includes crystalline grains, grain boundaries and amorphous material. The project will utilize poly(thiophenes) and poly(thieno-thiophenes), considered as high-performance polymeric semiconductors. The approach parallels that used with heteroepitaxy and graphoepitaxy to achieve long-range order. Scanning probe techniques, high resolution synchrotron-based X-ray diffraction, and in situ thermal annealing studies will be conducted along with molecular dynamics (MD) simulations of micro-structure evolution. Coupled electrical and optical characterization to separate the effect of different aspects of the micro-structure on the materials' performance will be carried out, and experimental measurements will be augmented by modeling of charge transport. The density-of-states of the semiconductor will be characterized with sub-bandgap absorption spectroscopies. Non-technical: The project addresses basic research issues in a topical area of materials science having high technological relevance. The project provides unique opportunities for graduate and undergraduate training in an interdisciplinary field. In addition to Stanford undergraduates, the PI will work pro-actively to attract underrepresented minority students to his laboratory through an Engineering Diversity Program (EDP). The research will also be used as a vehicle to "re-excite" local high-school Science teachers participating in an outreach program. The PI plans to lecture at local high schools and participate in national outreach days organized by EDP.