Department of Materials Engineering and Convergence Technology and ERI , Gyeongsang National University , Jinju 660-701 , Republic of Korea.
Photo-electronic Hybrids Research Center , Korea Institute of Science and Technology , Seoul 02792 , Republic of Korea.
ACS Appl Mater Interfaces. 2019 Sep 25;11(38):35185-35192. doi: 10.1021/acsami.9b09607. Epub 2019 Sep 10.
We report two newly synthesized naphthalene diimide (NDI)-based conjugated polymers, poly[()-2,7-bis(2-decyltetradecyl)benzo[][3,8]phenanthroline-1,3,6,8(2,7)-tetraone-vinylene-thiophene-vinylene] (PNDI-VTV) and poly[()-2,7-bis(2-decyltetradecyl)benzo[][3,8]phenanthroline-1,3,6,8(2,7)-tetraone-vinylene-selenophene-vinylene] (PNDI-VSV) with different donor units as electron-transporting organic semiconductors for organic field-effect transistors (OFETs). Furthermore, we study the effect of vinylene position on electron transport in the NDI polymers by using two similar polymers but with thiophene-vinylene-thiophene (PNDI-TVT) instead of vinylene-thiophene-vinylene or selenophene-vinylene-selenophene (PNDI-SVS) instead of vinylene-selenophene-vinylene. By incorporating vinylene between thiophene (or selenophene) units, the resulting NDI-based polymers PNDI-VTV and PNDI-VSV show larger backbone planarity than PNDI-TVT and PNDI-SVS. The polymers with a shorter acceptor monomer unit (PNDI-VTV and PNDI-VSV) show a strong face-on orientation, whereas those with a longer monomer unit (PNDI-TVT and SVS) exhibit a mixed face-on and edge-on orientation by two-dimensional grazing incidence X-ray diffraction. Optimized PNDI-VTV and PNDI-VSV OFETs exhibit electron mobilities of 0.043 and 0.7 cm/(V·s), which is quite lower than those of PNDI-TVT and PNDI-SVS. In addition, the activation energies for electron transport of PNDI-VTV and PNDI-VSV were larger than those of PNDI-TVT and PNDI-SVS. Overall, this research provides the insight that the molecular alignment on the substrate can be controlled by the sequence of rigid acceptor monomer molecules for improving the electron transport of NDI polymers.
我们报告了两种新合成的萘二酰亚胺（NDI）基共轭聚合物，聚[（）-2,7-双（2-癸基十四烷基）苯并[][3,8]菲咯啉-1,3,6,8(2,7)-四酮-乙烯基噻吩-乙烯基]（PNDI-VTV）和聚[（）-2,7-双（2-癸基十四烷基）苯并[][3,8]菲咯啉-1,3,6,8(2,7)-四酮-乙烯基硒吩-乙烯基]（PNDI-VSV），它们具有不同的供体单元，可用作有机场效应晶体管（OFET）的电子传输有机半导体。此外，我们通过使用两种类似的聚合物，但用噻吩-乙烯基-噻吩（PNDI-TVT）代替乙烯基-噻吩-乙烯基或硒吩-乙烯基-硒吩（PNDI-SVS）代替乙烯基-硒吩-乙烯基，研究了乙烯基位置对 NDI 聚合物中电子传输的影响。通过在噻吩（或硒吩）单元之间引入乙烯基，得到的基于 NDI 的聚合物 PNDI-VTV 和 PNDI-VSV 比 PNDI-TVT 和 PNDI-SVS 具有更大的主链平面性。具有较短受体单体单元的聚合物（PNDI-VTV 和 PNDI-VSV）表现出强烈的面向上取向，而具有较长单体单元的聚合物（PNDI-TVT 和 SVS）通过二维掠入射 X 射线衍射表现出面向上和边缘向上的混合取向。优化后的 PNDI-VTV 和 PNDI-VSV OFET 表现出 0.043 和 0.7 cm/(V·s) 的电子迁移率，这明显低于 PNDI-TVT 和 PNDI-SVS。此外，PNDI-VTV 和 PNDI-VSV 的电子输运活化能大于 PNDI-TVT 和 PNDI-SVS。总的来说，这项研究提供了一个见解，即通过刚性受体单体分子的序列控制分子在衬底上的取向可以改善 NDI 聚合物的电子输运。
