The influence of nitrogen position on charge carrier mobility in enantiopure aza[6]helicene crystals.
The influence of nitrogen position on charge carrier mobility in enantiopure aza[6]helicene crystals.
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DOI：
10.1039/c8cp07603k
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发表时间：
2018-12
期刊：
影响因子：
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通讯作者：
Francesco Salerno;Beth Rice;Julia A. Schmidt;M. Fuchter;J. Nelson;K. Jelfs
中科院分区：
文献类型：
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作者：
Francesco Salerno;Beth Rice;Julia A. Schmidt;M. Fuchter;J. Nelson;K. Jelfs
有机半导体的性质取决于所涉及分子的化学结构及其在固态中的排列方式。提取每个单独因素的影响是具有挑战性的，因为分子结构的微小变化通常会显著改变晶体堆积，从而改变固态结构。在这里，我们使用计算探索的影响，氮的位置上的电荷迁移率的手性有机分子时，晶体包装保持不变。为了确定最佳的超分子基序，以提高载流子迁移率的对映体纯氮杂[6]螺烯晶体共享相同的包装的一系列的转移积分进行了分析。所考虑的区域异构体仅在芳族骨架中的氮原子的定位上不同。模拟表明，即使是化学结构的这种微小变化也会对晶体中的电荷传输产生强烈影响，导致电荷迁移率的差异高达一个数量级。一些相互堆积互锁的氮杂[6]螺烯异构体显示出高的HOMO-HOMO积分（高达70 meV），而以平移对称排列的分子通常提供最高的LUMO-LUMO积分（40 - 70 meV）。由于许多结果在直观上并不明显，计算方法为新的半导体有机材料的设计提供了额外的见解。
The properties of an organic semiconductor are dependent on both the chemical structure of the molecule involved, and how it is arranged in the solid-state. It is challenging to extract the influence of each individual factor, as small changes in the molecular structure often dramatically change the crystal packing and hence solid-state structure. Here, we use calculations to explore the influence of the nitrogen position on the charge mobility of a chiral organic molecule when the crystal packing is kept constant. The transfer integrals for a series of enantiopure aza[6]helicene crystals sharing the same packing were analysed in order to identify the best supramolecular motifs to promote charge carrier mobility. The regioisomers considered differ only in the positioning of the nitrogen atom in the aromatic scaffold. The simulations showed that even this small change in the chemical structure has a strong effect on the charge transport in the crystal, leading to differences in charge mobility of up to one order of magnitude. Some aza[6]helicene isomers that were packed interlocked with each other showed high HOMO-HOMO integrals (up to 70 meV), whilst molecules arranged with translational symmetry generally afforded the highest LUMO-LUMO integrals (40-70 meV). As many of the results are not intuitively obvious, a computational approach provides additional insight into the design of new semiconducting organic materials.