Nonlinear Density Dependence of Singlet Fission Rate in Tetracene Films
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- 作者：Bo Zhang ; Chunfeng Zhang ; Rui Wang ; Zhanao Tan ; Yunlong Liu ; Wei Guo ; Xiaoling Zhai ; Yi Cao ; Xiaoyong Wang ; Min Xiao
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2014
- 出版时间：October 16, 2014
- 年：2014
- 卷：5
- 期：20
- 页码：3462-3467
- 全文大小：377K
- ISSN：1948-7185
文摘
Singlet fission holds the potential to dramatically improve the efficiency of solar energy conversion by creating two triplet excitons from one photoexcited singlet exciton in organic semiconductors. It is generally assumed that the singlet-fission rate is linearly dependent on the exciton density. Here we experimentally show that the rate of singlet fission has a nonlinear dependence on the density of photoexcited singlet excitons in tetracene films with small crystalline grains. We disentangle the spectrotemporal features of singlet and triplet dynamics from ultrafast spectroscopic data with the algorithm of singular value decomposition. The correlation between their temporal dynamics indicates a superlinear dependence of fission rate on the density of singlet excitons, which may arise from excitonic interactions.