Photoinduced Dynamics of Charge Separation: From Photosynthesis to Polymer鈥揊ullerene Bulk Heterojunctions
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- 作者：Jens Niklas ; Serge Beaupr茅 ; Mario Leclerc ; Tao Xu ; Luping Yu ; Andreas Sperlich ; Vladimir Dyakonov ; Oleg G. Poluektov
- 刊名：Journal of Physical Chemistry B
- 出版年：2015
- 出版时间：June 18, 2015
- 年：2015
- 卷：119
- 期：24
- 页码：7407-7416
- 全文大小：413K
- ISSN：1520-5207
文摘
Understanding charge separation and charge transport is crucial for improving the efficiency of organic solar cells. Their active media are based on organic molecules and polymers, serving as both light-absorbing and transport layers. The charge-transfer (CT) states play an important role, being intermediate for free carrier generation and charge recombination. Here, we use light-induced electron paramagnetic resonance spectroscopy to study the CT dynamics in blends of the polymers P3HT, PCDTBT, and PTB7 with the fullerene derivative C60-PCBM. Time-resolved EPR measurements show strong spin-polarization patterns for all polymer鈥揻ullerene blends, confirming predominant generation of singlet CT states and partial orientation ordering near the donor鈥揳cceptor interface. These observations allow a comparison with charge separation processes in molecular donor鈥揳cceptor systems and in natural and artificial photosynthetic assemblies, and thus the elucidation of the initial steps of sequential CT in organic photovoltaic materials.