当前位置: X-MOL 学术Org. Electron. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Charge transfer properties of diphenyl substituted cyclopentadithiophene organic semiconductors: The role of fluorine and malononitrile substitutions and crystal ordering
Organic Electronics ( IF 3.2 ) Pub Date : 2017-08-01 , DOI: 10.1016/j.orgel.2017.07.045
Yuexing Zhang , Paul M. Lahti , Dimitrios Maroudas

The geometry and electronic structures of four cyclopentadithiophene (CPD) derivatives in their crystals are systematically studied through density functional theory (DFT) calculations. The factors influencing the CPDs' semiconductor nature and charge carrier mobility are analyzed in detail, revealing the different roles of fluorine and dicyanomethylene in the CPDs examined in this study. Malononitrile substitutions show a large effect in lowering the molecular LUMO energy level but induce a smaller charge transfer integral due to the resulting reduced crystal order caused by the resulting steric hindrance. In comparison, although F substitution lowers the LUMO level more weakly than C(CN)2 substitution, it allows the molecule to retain a more planar configuration with more orbital delocalization, and the crystals of the F substituted compounds are more ordered than those of the C(CN)2 substituted compounds. Overall, this comparison can explain why F substitution is a more effective method to cause a transition of a p-type semiconductor to n-type. Crystal ordering plays a significant role in determining the charge transfer mobility in devices. In spite of the advantage offered by dicyanomethylene substitution in terms of charge injection barrier compared to fluorine substitution, the reduced crystal order caused by C(CN)2 limits the charge transfer in CPDs with C(CN)2 substitution. The validity of these findings can be generalized, which is expected to contribute to the rational design of n-type semiconductors based on CPDs.



中文翻译:

二苯基取代的环戊二噻吩有机半导体的电荷转移性质:氟和丙二腈取代的作用和晶体有序化

通过密度泛函理论(DFT)计算,系统研究了四种环戊二噻吩(CPD)晶体中的几何结构和电子结构。详细分析了影响CPD半导体性质和电荷载流子迁移率的因素,揭示了氟和二氰基亚甲基在本研究中研究的CPD中的不同作用。丙二腈取代在降低分子LUMO能级上显示出很大的作用,但由于由空间位阻导致的晶体序降低,引起较小的电荷转移积分。相比之下,尽管F取代比C(CN)2更弱地降低了LUMO含量取代时,它使分子保留了更多的轨道离域的更平面构型,并且F取代的化合物的晶体比C(CN)2取代的化合物的晶体更有序。总体而言,该比较可以解释为什么F替代是导致p型半导体过渡到n型的更有效方法。晶体排序在确定器件中的电荷转移迁移率方面起着重要作用。尽管由二氰基亚甲基取代在相对于氟取代的电荷注入阻挡方面所提供的优点,由C(CN)的降低的晶体顺序2只限制在的CPDs电荷转移具有C(CN)2代换。可以概括这些发现的有效性,这有望有助于基于CPD的n型半导体的合理设计。

更新日期:2017-08-01
down
wechat
bug