Center for Nano and Molecular Science and Technology, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States.
J Phys Chem B. 2012 Aug 16;116(32):9866-72. doi: 10.1021/jp306674t. Epub 2012 Aug 3.
Herein we describe the use of regioregular (rr-) and regiorandom (rra-) P3HT as models to study energy transfer in ordered and disordered single conjugated polymer chains. Single molecule fluorescence spectra and excitation/emission polarization measurements were compared with a Förster resonance energy transfer (FRET) model simulation. An increase in the mean single chain polarization anisotropy from excitation to emission was observed for both rr- and rra-P3HT. The peak emission wavelengths of rr-P3HT were at substantially lower energies than those of rra-P3HT. A simulation based on FRET in single polymer chain conformations successfully reproduced the experimental observations. These studies showed that ordered conformations facilitated efficient energy transfer to a small number of low-energy sites compared to disordered conformations. As a result, the histograms of spectral peak wavelengths for ordered conformations were centered at much lower energies than those obtained for disordered conformations. Collectively, these experimental and simulated results provide the basis for quantitatively describing energy transfer in an important class of conjugated polymers commonly used in a variety of organic electronics applications.
在此，我们使用规则（rr-）和无规（rra-）P3HT 作为模型，研究有序和无序单共轭聚合物链中的能量转移。我们比较了单分子荧光光谱和激发/发射偏振测量结果与Förster 共振能量转移（FRET）模型模拟结果。对于 rr-P3HT 和 rra-P3HT，均观察到从激发到发射的平均单链偏振各向异性增加。rr-P3HT 的峰值发射波长的能量显著低于 rra-P3HT。基于单聚合物链构象的 FRET 模拟成功地再现了实验观察结果。这些研究表明，与无序构象相比，有序构象有利于将能量有效转移到少数低能量位置。因此，有序构象的光谱峰波长直方图的中心位于比无序构象低得多的能量。总之，这些实验和模拟结果为定量描述在各种有机电子应用中广泛使用的一类重要共轭聚合物中的能量转移提供了基础。
