Hedley Gordon J, Steiner Florian, Vogelsang Jan, Lupton John M
WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK.
Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040, Regensburg, Germany.
Small. 2018 Dec;14(51):e1804312. doi: 10.1002/smll.201804312. Epub 2018 Nov 16.
Measuring the nanoscale organization of conjugated polymer chains used in organic photovoltaic (OPV) blends is vital if one wants to understand the materials. This is made very difficult with high efficiency OPV polymers such as PTB7 that form aggregates, as a lack of periodicity and a high degree of disorder make understanding of the nanoscale organization challenging. Here, single molecule spectroscopy is used to observe single chains and aggregates of PTB7. Using four detectors the photoluminescence intensity, wavelength, polarization, and lifetime are simultaneously monitored. Fast (milliseconds) and slow (seconds) fluctuations are observed over a time window of 30 s in all of these observables from single aggregates and chains as individual chromophores activate and deactivate, leading to dynamical changes in the emission spectrum and dipole orientation. This information can be used to help reconstruct the spatial and spectral organization of disordered aggregates of PTB7, thereby adding valuable new information on how the chains are arranged in space.
如果想要了解有机光伏（OPV）共混物中使用的共轭聚合物链的纳米级组织，对其进行测量至关重要。对于像PTB7这样形成聚集体的高效OPV聚合物来说，这变得非常困难，因为缺乏周期性和高度无序使得对纳米级组织的理解具有挑战性。在这里，单分子光谱用于观察PTB7的单链和聚集体。使用四个探测器同时监测光致发光强度、波长、偏振和寿命。在30秒的时间窗口内，从单个聚集体和链中观察到所有这些可观测值都存在快速（毫秒级）和缓慢（秒级）的波动，这是由于单个发色团的激活和失活导致发射光谱和偶极取向的动态变化。这些信息可用于帮助重建PTB7无序聚集体的空间和光谱组织，从而为链在空间中的排列方式增添有价值的新信息。
