学术报告：Prof. Sun Wenfang（USA）
时间: 2015-07-25 作者: 浏览次数: 1956
报告题目：Heteroleptic Cationic Iridium(III) Complexes as Nonlinear Absorbing Materials
报 告 人：Prof. Sun Wenfang Department of Chemistry and Biochemistry, North Dakota State University, USA
报告时间：2014年6月14日下午14点30分
报告地点：物理科技楼101
Abstract::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 -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 -conjugation on the diimine ligand increases the triplet excited-state lifetime and broaden the triplet excited-state absorption band; while extended -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.
报 告 人：Prof. Sun Wenfang Department of Chemistry and Biochemistry, North Dakota State University, USA
报告时间：2014年6月14日下午14点30分
报告地点：物理科技楼101
Abstract::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 -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 -conjugation on the diimine ligand increases the triplet excited-state lifetime and broaden the triplet excited-state absorption band; while extended -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.