Singlet-triplet annihilation limits exciton yield in poly(3-hexylthiophene).
Singlet-triplet annihilation limits exciton yield in poly(3-hexylthiophene).
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DOI：
10.1103/physrevlett.112.137402
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发表时间：
2014-04
影响因子：
8.6
通讯作者：
F. Steiner;J. Vogelsang;J. Lupton
中科院分区：
文献类型：
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作者：
F. Steiner;J. Vogelsang;J. Lupton
结合单分子光谱技术的链长和形态的控制提供了一个全面的电子物理图片的激发态损失的原型共轭聚合物聚（3-hexylthiophene）（P3 HT）。我们的研究揭示了一个普遍的自猝灭机制，单重态-三重态激子湮灭的基础上，这占了一个单一的P3 HT链的荧光量子产率的显着损失之间的解决方案（未折叠）和散装（折叠）状态。三重态激子从根本上限制了有机光伏材料的荧光，这影响了单重态激子向分离的电荷载流子的转化，降低了在高激发密度下收获能量的效率。激发子间的相互作用是如此有效，一个单一的P3 HT链的顺序100 kDa的重量表现得像一个2级系统，表现出完美的光子反聚束。
Control of chain length and morphology in combination with single-molecule spectroscopy techniques provides a comprehensive photophysical picture of excited-state losses in the prototypical conjugated polymer poly(3-hexylthiophene) (P3HT). Our examination reveals a universal self-quenching mechanism, based on singlet-triplet exciton annihilation, which accounts for the dramatic loss in fluorescence quantum yield of a single P3HT chain between its solution (unfolded) and bulklike (folded) state. Triplet excitons fundamentally limit the fluorescence of organic photovoltaic materials, which impacts the conversion of singlet excitons to separated charge carriers, decreasing the efficiency of energy harvested at high excitation densities. Interexcitonic interactions are so effective that a single P3HT chain of order 100 kDa weight behaves like a 2-level system, exhibiting perfect photon antibunching.