We demonstrate that the product of photoinduced electron transfer between a conjugated polymer host and a dilute molecular sensitizer is controlled by the structural state of the polymer. Ordered semicrystalline solids exhibit free charge generation, while disordered polymers in the melt phase do not. We use photoluminescence (PL) and time-resolved microwave conductivity (TRMC) measurements to sweep through polymer melt transitions in situ. Free charge generation measured by TRMC turns off upon melting, whereas PL quenching of the molecular sensitizers remains constant, implying unchanged electron transfer efficiency. The key difference is the intermolecular order of the polymer host in the solid state compared to the melt. We propose that this order–disorder transition modulates the localization length of the initial charge-transfer state, which controls the probability of free charge formation.

中文翻译：

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离域化驱动共轭聚合物薄膜中的免费电荷产生

我们证明了共轭聚合物主体和稀分子敏化剂之间的光诱导电子转移的产物是由聚合物的结构状态控制的。有序的半结晶固体表现出自由电荷产生，而熔融相中的无序聚合物则没有。我们使用光致发光（PL）和时间分辨的微波电导率（TRMC）测量来原位扫描聚合物的熔融转变。通过TRMC测量的自由电荷生成在熔化时关闭，而分子敏化剂的PL猝灭保持恒定，这意味着电子转移效率不变。关键区别是与熔融状态相比，固态的聚合物主体的分子间顺序。我们建议这种有序-无序跃迁调节初始电荷转移状态的定位长度，