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

Stanford University, Stanford CA

Investigators

Abstract

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.