报告题目：Heteroleptic Cationic Iridium(III) Complexes as Nonlinear Absorbing Materials

主讲人：美国北达科他州立大学化学与生物化学系  孙文芳教授

时间：2014年6月11日（周三）下午15：30

地点：江浦校区 笃行楼316西

孙文芳，博士，美国北达克他州州立大学（North Dakota State University）化学与生物化学系教授，“Walter F. and Verna Gerhts”讲席教授，北京大学、武汉大学和江苏大学名誉教授。孙教授先后在武汉大学、中国科学院、伯明翰阿拉巴马大学以及北达科他州立大学学习及工作，长期从事有机光功能材料的设计、合成、光物理性能及应用研究，在平面正方形铂配合物、大环金属类卟啉配合物以及金纳米材料的非线性光学性质和光限幅应用研究等方向上处于国际领先地位,是国际上公认的金属有机配合物光限幅材料研究专家。主持承担美国国家自然科学基金会、美国陆军研究所、美国空军研究所、美国农业部、美国化学会以及EPSCoR基金资助项目。已在J. Am. Chem. Soc.、Chem. Eur. J.、Chem. Mater.、Dalton Trans., Inorg. Chem.等国际著名学术期刊上发表SCI论文100余篇。

Organic materials with broadband nonlinear absorption in the visible to the near-IR region are desired for a variety of photonic device applications.  Ir(III) complexes are promising candidates for these applications due to the weak direct transition from the ground state to the triplet excited state and the broadband excited-state absorption in the visible to the near-IR region.  The ease of structural modifications also makes them good candidates for structure-property correlation study.  To optimize the reverse saturable absorption (RSA) of Ir(III) complexes, we designed and synthesized several series of heteroleptic cationic Ir(III) complexes with different diimine ligands, different substituents on the cyclometalating ligands and different degrees of p-conjugation on the diimine ligand and/or cyclometalating ligands.  The photophysical properties of these complexes, including UV-vis absorption, emission, and transient absorption were systematically investigated.  Reverse saturable absorption of the complexes was demonstrated at 532 nm using ns laser pulses.  It was found that extending the p-conjugation on the diimine ligand increases the triplet excited-state lifetime and broaden the triplet excited-state absorption band; while extended p-conjugation on the cyclometalating C^N ligands decreases the triplet excited-state lifetime and reduce the triplet excited-state absorption.  Different diimine ligands and different substituents on the C^N ligand also influence the triplet excited-state lifetime and triplet excited-state absorption significantly, which in turn affect the RSA pronouncedly.

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                          2014.06.05