High Dielectric Constant Semiconducting Poly(3-alkylthiophene)s from Side Chain Modification with Polar Sulfinyl and Sulfonyl Groups
High Dielectric Constant Semiconducting Poly(3-alkylthiophene)s from Side Chain Modification with Polar Sulfinyl and Sulfonyl Groups
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DOI：
10.1021/acs.macromol.8b01895
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发表时间：
2018-11-27
期刊：
影响因子：
5.5
通讯作者：
Sauve, Genevieve
中科院分区：
文献类型：
--
作者：
Wang, Chunlai;Zhang, Zhongbo;Sauve, Genevieve
人们对设计和开发高介电常数（ε（r））有机半导体越来越感兴趣，因为它们具有通过促进激子解离、减少双分子电荷载流子复合和通过电荷屏蔽潜在地增强电荷载流子迁移率来进一步增强器件性能的潜力。在这项研究中，一类新的具有高介电常数（r）的半导体聚合物，即，合成了亚磺酰化和磺酰化的聚（3-烷基噻吩）（P3 ATs）。由于高极性甲基亚磺酰基和甲基磺酰基侧基的有效旋转（即，取向极化），基于使用金/半导体聚合物/SiO2/n掺杂Si配置的准确电容测量，这些功能化P3 AT实现了高epsilon（r）值。例如，在兆赫和室温下的ε（r）从区域规整的聚（3-己基噻吩）（P3 HT）的3.75增加到亚磺酰化的P3 AT聚合物的7.4和磺酰化的P3 AT聚合物的8.1-9.3。这些值是迄今为止报道的共轭聚合物的最高的ε（r）。掠入射广角X射线衍射结果表明，这些极性基团降低了聚噻吩主链的结晶度，并干扰了晶体结构中的π-π堆积。因此，它们的光学性质，包括紫外-可见吸收和荧光，在薄膜中发生变化。从该研究中，亚磺酰化聚合物可能有希望在高介电常数（r）和保持有利的聚噻吩π-π堆叠结构之间提供平衡以用于器件应用。
There is growing interest in designing and developing high dielectric constant (epsilon(r)) organic semiconductors because they have the potential to further enhance device performance by promoting exciton dissociation, reducing bimolecular charge carrier recombination, and potentially enhancing charge carrier mobility via charge screening. In this study, a new class of semiconducting polymers with high epsilon(r), i.e., sulfinylated and sulfonylated poly(3-alkylthiophene)s (P3ATs), were synthesized. Because of efficient rotation of highly polar methylsulfinyl and methylsulfonyl side groups (i.e., orientational polarization), high epsilon(r) values were achieved for these functionalized P3ATs based on an accurate capacitance measurement using a gold/semiconducting polymer/SiO2/n-doped Si configuration. For example, the epsilon(r) at megahertz and room temperature increased from 3.75 for the regioregular poly(3-hexylthiophene) (P3HT) to 7.4 for the sulfinylated and 8.1-9.3 for sulfonylated P3AT polymers. These values are among the highest epsilon(r) reported for conjugated polymers so far. Grazing-incident wide-angle X-ray diffraction results showed that these polar groups decreased the crystallinity for the polythiophene backbones and interfered with the pi-pi stacking in the crystalline structure. Consequently, their optical properties, including UV-vis absorption and fluorescence, changed in thin films. From this study, the sulfinylated polymer may be promising to provide a balance between high epsilon(r) and preserving favorable polythiophene pi-pi stacking structure for device applications.