Yang Caiyao, Cao Jiawen, Lin Jin-Liang, Wu Hao, Zhang Hao-Li, Guo Xuefeng
Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing 100871, P. R. China.
School of Materials Science and Engineering, Peking University, Beijing 100871, P. R. China.
J Am Chem Soc. 2024 Oct 30;146(43):29703-29711. doi: 10.1021/jacs.4c10924. Epub 2024 Oct 19.
The advancement of molecular electronics endeavors to build miniaturized electronic devices using molecules as the key building blocks by harnessing their internal structures and electronic orbitals. To date, linear planar conjugated or cross-conjugated molecules have been extensively employed in the fabrication of single-molecule devices, benefiting from their good conductivity and compatibility with electrode architectures. However, the development of multifunctional single-molecule devices, particularly those with unique charge transport properties, necessitates a more rigorous selection of molecular materials. Among different assortments of molecules suited for the construction of molecular circuits, Spiro-conjugated structures, specifically spirobifluorene derivatives, stand out as promising candidates due to their distinctive electronic properties. In this work, we focus on the charge transport characteristics of Spiro-conjugated molecules sandwiched between graphene nanogaps. Experiments reveal significant Coulomb blockade and distinct negative differential conductance effects. Beyond two-terminal device measurements, solid-state gate electrodes are utilized to create single-molecule transistors, successfully modulating the molecular energy levels to achieve an on/off ratio exceeding 1000. This endeavor not only offers valuable insights into the design and fabrication of future practical molecular devices, blessed with enhanced performance and functionality, but also presents a new paradigm for the investigation of fundamental physical phenomena.
分子电子学的发展致力于利用分子的内部结构和电子轨道，将分子作为关键构建单元来制造小型化电子设备。迄今为止，线性平面共轭或交叉共轭分子因其良好的导电性以及与电极结构的兼容性，已被广泛应用于单分子器件的制造。然而，多功能单分子器件的发展，尤其是那些具有独特电荷传输特性的器件，需要对分子材料进行更严格的筛选。在适合构建分子电路的不同种类分子中，螺共轭结构，特别是螺二芴衍生物，因其独特的电子性质而成为有前途的候选者。在这项工作中，我们专注于夹在石墨烯纳米间隙之间的螺共轭分子的电荷传输特性。实验揭示了显著的库仑阻塞和明显的负微分电导效应。除了双端器件测量外，还利用固态栅电极制造单分子晶体管，成功调节分子能级以实现超过1000的开/关比。这一努力不仅为未来具有更高性能和功能的实用分子器件的设计和制造提供了有价值的见解，也为基础物理现象的研究提出了一种新范式。
