两个阶段的电荷分离通过分子二合体的部分电荷转移状态
Taeyeon Kim1, Woojae Kim1, Olena Vakuliuk2
1Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems , Yonsei University , Seoul 03722 , Korea.
Journal of the American Chemical Society
|December 24, 2019
概括
我们发现了一个两步的电荷分离过程, 这种机制涉及部分电荷转移状态,对于有机电子中的有效电荷分离至关重要.
科学领域:
- 分子光物理学和电荷转移动力学.
背景情况:
- 电荷分离 (CS) 通常在弱合的供体-接受体系统中观察到.
- 了解CS中的中间状态对于优化分子设备至关重要.
研究的目的:
- 研究一种新型的二步电荷分离过程.
- 阐明部分电荷转移 (CT) 状态在有效电荷分离中的作用.
主要方法:
- 使用过渡吸收,光向上转换和过渡冲动刺激拉曼光谱.
- 分析了激发状态的吸收光谱和光灭.
- 研究振动频率的变化以量化CT特征.
主要成果:
- 通过光激发启动的两步CS过程,在达到最终CS状态之前进行部分CT状态.
- 受溶剂和结构波动影响的部分CT状态的放松时间 (1-20 ps在烯中,700 fs在THF中).
- 通过振动频率分析量化了明亮和部分CT状态 (分别为0.1e和0.5e).
结论:
- DPP-PP二极管通过独特的部分CT状态表现出高效的电荷分离,这在pyrrolo[3,2-b]pyrrole核心中得到了强大的电子通信.
- 这种机制在有机光伏和发光二极管中具有潜在的应用.
- 这项研究提供了对CT动态和分子结构对电荷分离效率的影响的定量见解.
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