Influence of N-introduction in pentacene on the electronic structure and excited electronic states.
Influence of N-introduction in pentacene on the electronic structure and excited electronic states.
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并五苯中N的引入对电子结构和激发电子态的影响。
DOI：
10.1039/d1cp05273j
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
P. Tegeder
中科院分区：
文献类型：
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作者：
Marvin Hoffmann;M. Ajdari;Felix Landwehr;Olena Tverskoy;U. Bunz;A. Dreuw;P. Tegeder
N-杂多环芳香族化合物是一种很有前景的有机半导体，可用于场效应晶体管和太阳能电池。因此，有机/金属界面和薄膜的电子结构对于有机分子器件的性能至关重要。在这里，我们利用振动和电子高分辨率电子能量损失光谱并结合最先进的量子化学计算，研究了吸附在 Au(111) 上的 6,7,12,13-四氮杂五苯 (TAP) 的结构和电子性质。在单层和多层中，TAP 以平面吸附几何形状吸附，分子主链平行于金基底取向。指定了最低激发电子单重态 (S) 以及三重态 (T) 的能量。发现光学间隙（S0 → S1 跃迁）为 1.6 eV，T1 能量为 1.2 eV。此外，与之前研究的并五苯 (PEN) 和 6,13-二氮杂五苯 (6,13-DAP) 进行了彻底比较，详细解释了氮取代对电子结构的影响，特别是对紫外/可见吸收光谱中 α 带强度的影响。在 PEN、6,13-DAP 和 TAP 系列中，由于引入的氮原子对轨道能量的单独影响，α 能带（S0→S2 跃迁）的强度显着增强。
N-Heteropolycyclic aromatic compounds are promising organic semiconductors for applications in field effect transistors and solar cells. Thereby the electronic structure of organic/metal interfaces and thin films is essential for the performance of organic-molecule-based devices. Here, we studied the structural and the electronic properties of 6,7,12,13-tetraazapentacene (TAP) adsorbed on Au(111) using vibrational and electronic high-resolution electron energy loss spectroscopy in combination with state-of-the-art quantum chemical calculations. In the mono- and multilayer TAP adsorbs in a planar adsorption geometry with the molecular backbone oriented parallel to the gold substrate. The energies of the lowest excited electronic singlet states (S) as well as the triplet state (T) are assigned. The optical gap (S0 → S1 transition) is found to be 1.6 eV and the T1 energy 1.2 eV. In addition, thorough comparison to previously studied pentacene (PEN) and 6,13-diazapentacene (6,13-DAP) is made explaining in detail the influence of nitrogen substitution on the electronic structure and in particular on the intensity of the α-band in the UV/vis absorption spectrum. In the series PEN, 6,13-DAP, and TAP, the α-band (S0 → S2 transition) gains significantly in intensity due to individual effects of the introduced nitrogen atoms on the orbital energies.