CAREER: Understanding Morphology-Property Correlations in Conjugated Polymer Blends with Nanoscale Optoelectronic Probes

这个CAREER项目的科学目标是了解局部相分离形态如何影响共轭聚合物共混物中的电荷传输、分离、重组和注射。该方法涉及光激发电扫描探针显微镜和单分子光谱学的新组合。动力学和热力学现象控制相分离在溶液处理共轭聚合物薄膜将被解决。将立即关注半导体聚合物混合物的加工，表征和器件性能。将启动几个主题，包括：1)通过扫描探针制作空间、光谱和时间分辨的电荷产生和收集图，在纳米结构、光导供体/受体共混物中反卷积电荷产生和电荷传输；2)通过研究聚合物共混物中单掺杂分子和纳米级域的电致发光，了解电荷重组、发射、光化学和激子-载流子耦合的局部变化；3)绘制多相体系中电荷注入和电场分布随相组成和界面聚合物构象变化的高分辨率横向和纵向图；4)绘制共轭聚合物共混物中控制相分离的动力学和热力学图，以便利用纳米表面化学优化加工成所需的形态。微观模型将与观察到的电子特性相关，作为局部薄膜结构的函数，以帮助预测哪种形态将满足所需的材料性能目标。预测将根据实际设备测量的薄膜进行测试，以产生所选的形态。这些研究将通过与合成聚合物化学家和专门研究复杂凝聚相系统电子结构的理论家的密切合作而得到加强。该项目涉及电子/光子材料科学中具有技术相关性的基础研究问题。该项目是跨学科的，涉及化学、物理和材料科学的交叉，并在光伏和电致发光显示领域有直接的技术应用，这些领域很容易受到学生和公众的欢迎。该项目将被用来推进主要的教育目标：通过在华盛顿大学的物理化学课程中开发和整合基于计算机的、情境丰富的问题来改善本科教育；通过建立正式的研究生课程来改善研究生教育，该课程将教授口头沟通技巧，同时为那些代表性不足的K-12群体提供服务。综合研究和教学活动将为长期综合科学和教育计划奠定基础，该计划将持续到奖励期之后

The scientific goal of this CAREER project is to understand how local phase-separated morphology impacts charge transport, separation, recombination and injection in conjugated polymer blends. The approach involves novel combinations of electrical scanning-probe microscopy with optical excitation and single-molecule optical spectroscopy. Kinetic and thermodynamic phenomena governing phase separation in solution-processed conjugated polymer thin films will be addressed. Immediate attention will be given to processing, characterization, and device performance in blends of semiconducting polymers. Several themes will be initiated including: 1)deconvoluting charge generation and charge transport in nanostructured, photoconductive donor/acceptor blends by making spatially, spectrally, and time resolved charge generation and collection maps with scanning probes; 2)understanding local variations in charge recombination, emission, photochemistry, and exciton-carrier coupling by studying the electroluminescence from both single dopant molecules and nanoscale domains in polymer blends; 3)making high resolution lateral and vertical maps of charge injection and electric field distribution in multi-phase systems as a function of phase composition and polymer conformation at interfaces; 4)mapping the kinetic and thermodynamic governing phase separation in conjugated polymer blends in order to optimize processing into desired morphologies using nanopatterned surface chemistry. Microscopic models will be developed relevant to observed electronic properties as a function of local film structure to assist prediction of which morphologies will meet desired materials performance goals. Predictions will be tested against actual device measurements on films processed to yield the chosen morphology. These studies will be enhanced by close collaboration with both synthetic polymer chemists, and with theorists specializing in electronic structure in complex con-densed-phase systems. %%% The project addresses fundamental research issues in electronic/photonic materials science having technological relevance. The project is interdisciplinary involving the intersection of chemistry, physics, and materials science, and has direct technological applications in photovoltaics and electroluminescent displays--areas readily appreciated by students and the general public. The project will be leveraged to advance major educational goals: to improve undergraduate education through the development and incorporation of computer-based, context-rich problems into the physical chemistry curriculum at the University of Washington; and, to improve graduate education through the establishment of a formal graduate program that will teach verbal commu-nication skills while simultaneously serving outreach efforts targeting underrepresented K-12 groups. The integrated research and teaching activities will lay the foundation for a long-term integrated scientific and educational program that will last beyond the award period.***