Han Li, Wang Mei, Zhang Yifan, Cui Bin, Liu Desheng
School of Physics, Shandong University, Jinan 250100, China.
School of Physics and Electronic Engineering, Jining University, Qufu 273155, China.
Molecules. 2024 Oct 17;29(20):4912. doi: 10.3390/molecules29204912.
The reversible photo-induced conformation transition of a single molecule with a [5]helicene backbone has garnered considerable interest in recent studies. Based on such a switching process, one can build molecular photo-driven switches for potential applications of nanoelectronics. But the achievement of high-performance reversible single-molecule photoswitches is still rare. Here, we theoretically propose a 13,14-dimethylcethrene switch whose photoisomerization between the ring- and ring- forms can be triggered by ultraviolet (UV) and visible light irradiation. The electronic structure transitions and charge transport characteristics, concurrent with the photo-driven electrocyclization of the molecule, are calculated by the non-equilibrium Green's function (NEGF) in combination with density functional theory (DFT). The electrical conductivity bears great diversity between the closed and open configurations, certifying the switching behavior and leading to a maximum ratio of up to 10, which is considerable in organic junctions. Further analysis confirms the evident switching behaviors affected by the molecule-electrode interfaces in molecular junctions. Our findings are helpful for the rational design of organic photoswitches at the single-molecule level based on cethrene and analogous organic molecules.
近期研究中，具有[5]螺旋烯骨架的单分子可逆光诱导构象转变引起了广泛关注。基于这样的开关过程，可以构建用于纳米电子学潜在应用的分子光驱动开关。但高性能可逆单分子光开关的实现仍然很少见。在此，我们从理论上提出了一种13,14-二甲基并四苯开关，其环式和环式之间的光异构化可由紫外光（UV）和可见光照射触发。结合密度泛函理论（DFT），通过非平衡格林函数（NEGF）计算了与分子光驱动电环化同时发生的电子结构转变和电荷传输特性。在闭合和开放构型之间，电导率具有很大差异，证明了开关行为，并且导致高达10的最大比率，这在有机结中是相当可观的。进一步分析证实了分子结中分子-电极界面影响的明显开关行为。我们的研究结果有助于基于并四苯和类似有机分子在单分子水平上合理设计有机光开关。
