关于举行美国北达科他州立大学Wenfang Sun教授学术报告的通知
报告题目：Cationic Ir(III) Complexes as Nonlinear Absorbing Materials: The Influence of Ligand p-Conjugation on the Photo-physics and Excited-state Absorption
报告人： Wenfang Sun 教授（North Dakota State University）
报告时间：2016年6月23日（周四） 上午10:00
报告地点：国重 502会议室
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报告摘要：
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 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 via attaching p-conjugated substituent increased the triplet excited-state lifetime and broaden the triplet excited-state absorption band; while extending the p-conjugation of the cyclometalating C^N ligands via attaching p-conjugated substituent decreased the triplet excited-state lifetime and reduce the triplet excited-state absorption. In contrast, extending the p-conjugation of the diimine ligands via benzannulation red-shifted the charge-transfer absorption tail to the near-IR region but decreased the triplet lifetime; while benzannulation at the C^N ligand could pronouncedly prolong the triplet lifetime of the complexes. All these changes affected the RSA pronouncedly.
报告人简介：
Prof. Wenfang Sun is the James Meier Senior Professor and the Water F. and Verna Gehrts Presidential Professor at the Department of Chemistry and Biochemistry, North Dakota State University (NDSU). She received her B.S. degree in 1990 from Wuhan University, China; and her Ph.D. degree in Organic Chemistry from the Institute of Photographic Chemistry, Chinese Academy of Sciences in 1995. She was employed by this institute as an Assistant Professor in 1995, and then as an Associate Professor in 1996. She joined the Department of Physics, University of Alabama at Birmingham as a Postdoctoral Research Associate in 1997, and was promoted to a Research Assistant Professor in 1999. In 2001, she joined NDSU as an Assistant Professor, was tenured and promoted to an Associate Professor in 2007, and became a Full Professor and named the Walter F. and Verna Gehrts Professor in 2011. She has published 104 peer-reviewed journal papers and 23 conference full papers. She obtained over $7,000,000 research grants from NSF, the US Army Research Laboratory, ACS-PRF, USDA, etc. She received numerious awards, including the NSF CAREER Award (2005-2011), the James A. Meier Senior Professorship (2016), the NDSU Fred Waldron Award for Outstanding Research (2012), the NDSU Walter F. and Verna Gehrts Professorship (2011), the NDSU Bison Ambassadors Apple Polisher Honoree (2009), the NDSU Featured Faculty (2006), and the 2nd-Class Chinese Academy of Sciences Natural Science Award (2002). She organized/co-organized, or chaired more than 10 national or international symposiums and presented more than 80 invited talks or seminar at conferences and universities. Currently, she serves on the editorial board of four international chemistry journals. Her research program covers the organic/organometallic nonlinear optical materials, organic/organometallic light emitting materials, photosensitizers for photodynamic therapy, and optical sensors.
