在有机异构连接中减少重组和电容器类电荷积累
Kyra N Schwarz, Paul B Geraghty, Valerie D Mitchell
1Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom.
Journal of the American Chemical Society
|January 11, 2020
概括
研究人员发现特定的有机光伏 (OPV) 活性层形态产生纳米电场,显著减少电荷重组. 这允许更厚的OPV设备通过保护载体免受双分子重组而保持高效率.
科学领域:
- 材料科学
- 物理化学
- 有机电子
背景情况:
- 有机光伏 (OPV) 设备的效率正在提高,但电荷载体重组仍然是一个关键的限制.
- 再组合是由于光生成的电子和孔之间的扩散和库伦引力,特别是在接口.
研究的目的:
- 研究纳米电场在OPV活性层中抑制电荷重组的作用.
- 了解特定的活性层形态如何影响电荷载体动态和设备性能.
主要方法:
- 使用秒瞬态光谱探测载体动态.
- 测量了纳米电场和短暂的斯塔克效应.
- 分析了电荷载体重组率,并将其与理论预测 (朗格温理论) 进行了比较.
主要成果:
- 观察到一个显著的短暂的Stark效应 (∼487kV/cm) 归因于自由载体之间的电场.
- 与兰格温理论预测相比,确定了特定的活性层形态,从而创建能量级联,减少了约2000倍的重组.
- 由于载体密度增加和对重组的保护,这些形态的更厚的OPV膜 (> 600 nm) 保持了> 8%的效率.
结论:
- 在OPV活性层中的特定纳米级形态可以通过空间分离电荷来减轻双分子重组.
- 大量异质连接可以作为电容器,将分离的电荷存储在远离接口的地方.
- 这些发现表明通过形态控制进一步提高OPV的性能.
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