Charge localization across conjugated polymers is one of the most important features to control their overall photophysical processes including the intermolecular charge transfer (CT) with molecular acceptors at interfaces. Herein, we synthesize two azothiazole (ATz) conjugated polymers coupled with a dithiophene (BT) donor using either esters or non-esters as side chains. The non-ester side chain polymer (P₁ATz-BT) shows a strong emission quenching upon successful addition of 1,4-dicyanobenzene (DCB), as a molecular acceptor, via intermolecular CT. On the other hand, the ester side chain polymer (P₂ATzE-BT) does not exhibit such changes, indicating that the side chain has a significant impact on the photophysical processes of these polymers at the interface with molecular acceptors. Density functional theory (DFT) calculations and time-resolved photoluminescence measurements show that unlike P₁ATz-BT, the introduction of ester chains causes significant steric effects on the conformation of polymer backbones and the localization of electron density distributions in P₂ATzE-BT, which leads to the suppression of the charge transfer to the molecular acceptor. Our study provides the experimental and theoretical clues for understanding the tremendous impact of polymer side chains on photophysical processes with molecular acceptors, at interfaces. These findings pave the way toward controlling and optimizing the interfacial charge transfers in conjugated polymers.

中文翻译：

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侧链在偶氮噻唑-二噻吩共轭共聚物中电荷定位和转移中的作用


共轭聚合物的电荷定位是控制其整体光物理过程的最重要特征之一，包括界面分子受体的分子间电荷转移（CT）。在这里，我们使用酯或非酯作为侧链合成了两种与二噻吩（BT）供体偶联的偶氮噻唑（ATz）共轭聚合物。通过分子间 CT 成功添加 1,4-二氰基苯 (DCB) 作为分子受体后，非酯侧链聚合物 (P ₁ ATz-BT) 显示出强烈的发射猝灭。另一方面，酯侧链聚合物（P ₂ ATzE-BT）没有表现出这样的变化，表明侧链对这些聚合物在与分子界面处的光物理过程有显着影响。接受者。密度泛函理论（DFT）计算和时间分辨光致发光测量表明，与P ₁ ATz-BT不同，酯链的引入对聚合物主链的构象和电子密度分布的局域化产生了显着的空间效应在 P ₂ ATzE-BT 中，这导致电荷转移到分子受体的抑制。我们的研究为理解聚合物侧链对界面处分子受体的光物理过程的巨大影响提供了实验和理论线索。这些发现为控制和优化共轭聚合物中的界面电荷转移铺平了道路。