题目:Morphology and Photophysics in Conjugated Polymers-a study by Single Molecule/Aggregate Spectroscopy
报告人:胡中建 博士
单位:美国得克萨斯大学奥斯汀分校,纳米与分子科学技术研究中心
时间:2015/8/27 10:00
地点:纳米楼一楼报告厅
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个人简介:
胡中建,博士,2002年于曲阜师范大学获学士学位;2005年于中科院福建物构所获硕士学位(导师:王元生研究员);2011年于美国中佛罗里达大学纳米科技中心和化学系获博士学位。2011年至今,在美国得克萨斯大学奥斯汀分校纳米与分子科学技术研究中心做博后。 胡中建博士研究兴趣包括:单分子
报告摘要:
In developing high-performing conjugated polymers (CPs) for organic optoelectronics, a fundamental understanding about morphology-photophysics relationships is of vital significance. Here, we employ single molecule/aggregate spectroscopy, in conjunction with analyte systems with controlled structural features, to unmask the morphology and photophysics, from single polymer chain up to bulk state.
Effect of interchain morphology on energy migration was probed via nanoscale aggregates, which can be controllably assembled from single polymer chains using solvent vapor annealing. Fluorescence blinking behavior and photon correlation measurement were employed to study the energy migration behavior. Our data suggested highly ordered interchain packing is in favor of long-range interchain energy migration, while disordered packing, long interchain distance and competitive intrachain coupling significantly impede the interchain mechanism. In addition, the non-emissive excited states in CPs was studied with aggregates fabricated using a triblock copolymer in a series of poor solvent media. The fluorescence experimental results combined with quantum chemical calculations suggested that there exists a crossing of energy levels of charge-transfer (CT) and exciton states as a function of solvent dielectric. Fluorescence decay dynamics indicated that the CT-type states exist as a competitive channel of the formation of exciton-type states. Furthermore, composite polythiophene/fullerene aggregates were fabricated and fluorescence-voltage/single aggregate spectroscopy was developed to study charge trapping and excitations interactions in a hole-injection device. Pronounced deep trapping of free electrons at NP/dielectric interface and hole trapping by fullerene anions were reported.