π-Conjugated Polymers Incorporating a Novel Planar Quinoid Building Block with Extended Delocalization and High Charge Carrier Mobility
π-Conjugated Polymers Incorporating a Novel Planar Quinoid Building Block with Extended Delocalization and High Charge Carrier Mobility
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DOI：
10.1002/adma.201706557
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发表时间：
2018-05-29
影响因子：
29.4
通讯作者：
Kim, Dong-Yu
中科院分区：
文献类型：
--
作者：
Kim, Yunseul;Hwang, Hansu;Kim, Dong-Yu
成功地合成了两种新型含喹啉噻吩的共轭聚合物。通过结合一维核磁共振（NMR）和二维核Overhauser效应光谱分析，主要醌单体的异构体形式被清楚地确定为不对称Z，E-构型。通过与噻吩或联噻吩的Stille聚合来合成醌型聚合物。这两种醌型聚合物都表现出1.45 eV的低带隙和两性氧化还原行为，表明由于醌型骨架的扩展共轭。这些醌型聚合物在应用于有机场效应晶体管时显示出具有高电荷载流子迁移率的双极性行为。此外，通过偏心旋涂实现的聚合物链的径向排列导致器件性能的进一步改善，其中聚（醌式噻吩-联噻吩）表现出8.09 cm（2）V-1 s（-1）的高空穴迁移率，这是迄今为止醌式聚合物中的最高值。发现通过热退火或偏心旋涂的微结构改变有益地影响电荷传输。具有强π-π相互作用的结晶度的增强和由平面良好离域的醌型单元产生的纳米原纤结构被认为是高电荷载流子迁移率的原因。
Two novel conjugated polymers incorporating quinoidal thiophene are successfully synthesized. By combining 1D nuclear magnetic resonance (NMR) and 2D nuclear Overhauser effect spectroscopy analyses, the isomeric form of the major quinoid monomer is clearly identified as the asymmetric Z, E-configuration. The quinoidal polymers are synthesized via Stille polymerization with thiophene or bithiophene. Both quinoidal polymers exhibit the low band gap of 1.45 eV and amphoteric redox behavior, indicating extended conjugation owing to the quinoidal backbone. These quinoidal polymers show ambipolar behaviors with high charge carrier mobilities when applied in organic field-effect transistors. In addition, the radial alignment of polymer chains achieved by off-center spin-coating leads to further improvement of device performance, with poly(quinoidal thiophene-bithiophene) exhibiting a high hole mobility of 8.09 cm(2) V-1 s(-1), which is the highest value among the quinoidal polymers up to now. Microstructural alteration via thermal annealing or off-center spin-coating is found to beneficially affect charge transport. The enhancement of crystallinity with strong pi-pi interactions and the nanofibrillar structure arising from planar well-delocalized quinoid units is considered to be responsible for the high charge carrier mobility.