一个扭曲的三胞胎:由构造性障碍驱动的一系列电子接收器材料中的超快速交叉
Sai Shruthi Murali1,2, Joseph K Gallaher1,2, Céline Janiseck1
1School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington6012, New Zealand.
Journal of the American Chemical Society
|December 20, 2022
概括
控制单子和三元激子对于有机电子来说至关重要. 这项研究揭示了电子受体中的系统间交叉 (ISC) 在固态中加速,影响有机太阳能电池中的激子损失途径.
科学领域:
- 有机电子产品
- 光物理学
- 材料科学
背景情况:
- 单元和三元激子对于有机半导体设备如太阳能电池和LED来说至关重要.
- 对于优化设备性能和探索新能源转换机制来说,管理激子群体,特别是三重状态至关重要.
- 系统间交叉 (ISC) 是一个关键的光物理过程,它控制单元和三元激子之间的相互转换.
研究的目的:
- 设计,合成和描述具有受控激子动态的新型电子受体分子.
- 研究这些分子在溶液和固态中的系统间交叉 (ISC) 的速率和机制.
- 阐明分子结构和膜形态在促进有机电子中的潜在应用中的快速ISC的作用.
主要方法:
- 超快速的短暂吸收光谱
- 超高速宽带光发光谱学
- 密度函数理论 (DFT) 的计算
- 合成新的电子受体分子和寡甲模型系统
主要成果:
- 在溶液中观察到分子内三倍体的形成在几秒内,在固态中明显更快.
- 发现ISC的速度足以与有机太阳能电池中的电荷形成相竞争,这表明它在内在激子损失中的作用.
- DFT计算确定了与三重激发状态中的轨道π对称度的偏差,与灵活的烯环相关,对ISC至关重要.
- 在薄膜和溶剂玻璃中出现的 conformational 障碍被证明可以显著加速 ISC,即使在较低的温度下也是如此.
结论:
- 分子设计和对形状障碍的控制是有机半导体中调整ISC速率的关键.
- 电子受体中的快速ISC可以是有机太阳能电池的内在损失通道,影响设备的效率.
- 了解和控制ISC为有机电子材料中自旋状态的分子工程提供了一个框架.
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