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超大超极化扭曲pi电子系统电光色谱:合成,固态和溶液相结构特征,电子结构,线性和非线性光学特性,以及计算研究
Hu Kang1, Antonio Facchetti, Hua Jiang
1Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
Journal of the American Chemical Society
|February 21, 2007
概括
研究人员开发了用于电光应用的新扭曲pi电子系统. 这些分子表现出显著的电荷分离,并保持它们在溶液中的扭曲结构,导致高超极化和电光系数.
科学领域:
- 有机化学 有机化学
- 材料科学 材料科学 材料科学
- 非线性光学 不线性光学
背景情况:
- 开发用于电光 (EO) 应用的先进材料至关重要.
- 了解有机染色体中的结构属性关系是提高EO性能的关键.
研究的目的:
- 合成和描述新的扭曲pi电子系统电光色谱.
- 研究分子结构,聚合和溶解对光学特性的影响.
- 为了评估这些染色体在EO设备中的潜力.
主要方法:
- 晶体学和核磁共振 (NMR) 光谱学 (NOE,PGSE) 用于结构分析.
- 光学,红外和光光谱学用于表征.
- 电场诱导的直流电流第二和生成 (EFISH) 测量.
- 客宿主聚合物薄膜制造和电光系数 (r(33)) 测量.
- 高层次的量子化学计算 (SA-CASSCF).
主要成果:
- 合成具有大二面角 (80-89度) 的非传统扭曲pi电子系统.
- 在溶液中确认了持久的扭曲结构和zwitterionic特征.
- 在缩溶液和固态中观察中心对称聚合物形成.
- 史无前例的非线性光学特性:高极化度 (mubeta) 高达-488,000 x 10{\displaystyle -488000 x 10{\displaystyle -48{\displaystyle 10{\displaystyle 10}x10{\displaystyle 10}x10{\displaystyle 10{\displaystyle 10}x10{\displaystyle -48}x10{\displaystyle 10{{\displaystyle 10}x10}-48}) 均为前所未有.
- 高电光系数 (r(33) ~ 330 pm/V) 在极化聚合物薄膜中.
- 对超极化的起源和溶解效应的计算洞察力.
结论:
- 研究的扭曲染色体因其独特的结构和聚合行为而表现出异常的非线性光学特性.
- 这些发现表明设计高性能分子超极化和电光材料的新策略.
- 这项研究提供了对有机EO材料的结构性质相关性更深入的了解.
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When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
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