Osuna Reyes Malavé, Zhang Xinnan, Matzger Adam Jay, Hernandez Víctor, López Navarrete Juan Teodomiro
Department of Physical Chemistry, University of Malaga, 29071-Malaga, Spain.
J Phys Chem A. 2006 Apr 20;110(15):5058-65. doi: 10.1021/jp0607263.
In this article, we report the characterization of novel oligothienoacenes with five and seven fused thiophene rings, materials with potential applications in organic electronics. In contrast to usual alpha-linked oligothiophenes, these fused oligothiophenes have a larger band gap than most semiconductors currently used in the fabrication of organic field-effect transistors (OFETs) and therefore they are expected to be more stable in air. The synthesis of these fused-ring oligomers was motivated by the notion that a more rigid and planar structure should reduce defects (such as torsion about single bonds between alpha-linked units or S-syn defects) and thus improve conjugation for better charge-carrier mobility. The conjugational properties of these two molecular materials have been investigated by means of FT-Raman spectroscopy, revealing that conjugation still increases in passing from the five-ring oligomer to that with seven-rings. DFT and TDDFT quantum chemical calculations have been performed, at the B3LYP/6-31G level, to assess information regarding the minimum-energy molecular structure, topologies, and absolute energies of the frontier molecular orbitals (MOs.) around the gap, vibrational normal modes related to the main Raman features, and vertical one-electron excitations giving rise to the main optical absorptions.
在本文中，我们报道了具有五个和七个稠合噻吩环的新型低聚并噻吩的特性，这类材料在有机电子学领域具有潜在应用。与常见的α-连接的低聚噻吩不同，这些稠合的低聚噻吩具有比目前用于制造有机场效应晶体管（OFET）的大多数半导体更大的带隙，因此预计它们在空气中会更稳定。合成这些稠环低聚物的动机是这样一种观念，即更刚性和平面的结构应减少缺陷（例如α-连接单元之间单键的扭转或S-顺式缺陷），从而改善共轭以实现更好的电荷载流子迁移率。通过傅里叶变换拉曼光谱对这两种分子材料的共轭性质进行了研究，结果表明从五环低聚物到七环低聚物，共轭程度仍在增加。已在B3LYP/6-31G水平上进行了密度泛函理论（DFT）和含时密度泛函理论（TDDFT）量子化学计算，以评估有关最低能量分子结构、拓扑结构以及能隙周围前沿分子轨道（MOs）的绝对能量、与主要拉曼特征相关的振动简正模式以及产生主要光吸收的垂直单电子激发等信息。
