To understand how disorder within conjugated polymer aggregates influences the polaron generation process, we investigated poly(3-hexylthiophene) (P3HT) and a congeneric random copolymer incorporating 33 mol % substituent-free thiophene units (RP33). Steady-state absorption and fluorescence spectra showed that increasing the intrachain torsional disorder in aggregates increases the energy and breadth of the density of states (DOS). By extracting polaron dynamics in the transient absorption spectra, we found that an activation energy barrier of 0.05 eV is imposed on the charge separation process in P3HT, whereas that in RP33 is essentially barrierless. We also found that a significant amount of excitons in P3HT are deactivated by traps, while no trapped excitons are generated in RP33. This efficient polaron generation in RP33 was attributed to the excess energy and enhanced interchain delocalization of precursor states provided by the intrachain torsional disorder and the close-packing structure in the absence of hexyl substituents.

中文翻译：

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混乱在聚噻吩晶体结构域中链间离域和极化子产生的程度中的作用

为了了解共轭聚合物聚集体中的无序性如何影响极化子的产生过程，我们研究了聚（3-己基噻吩）（P3HT）和掺有33 mol％无取代基噻吩单元（RP33）的同类无规共聚物。稳态吸收和荧光光谱表明，聚集体中链内扭转紊乱的增加增加了态密度（DOS）的能量和宽度。通过提取瞬态吸收光谱中的极化子动力学，我们发现P3HT的电荷分离过程施加了0.05 eV的活化能垒，而RP33中的活化能垒本质上是无障碍的。我们还发现，陷阱使P3HT中的大量激子失活，而RP33中没有捕获到的激子。