Kong Gyu Don, Song Hyunsun, Yoon Seungmin, Kang Hungu, Chang Rakwoo, Yoon Hyo Jae
Department of Chemistry, Korea University, Seoul 02841, Korea.
Department of Chemistry, Kwangwoon University, Seoul 01897, Korea.
Nano Lett. 2021 Apr 14;21(7):3162-3169. doi: 10.1021/acs.nanolett.1c00406. Epub 2021 Apr 2.
Electrical breakdown is a critical problem in electronics. In molecular electronics, it becomes more problematic because ultrathin molecular monolayers have delicate and defective structures and exhibit intrinsically low breakdown voltages, which limit device performances. Here, we show that interstitially mixed self-assembled monolayers (imSAMs) remarkably enhance electrical stability of molecular-scale electronic devices without deteriorating function and reliability. The SAM of the sterically bulky matrix (SCBIPY rectifier) molecule is diluted with a skinny reinforcement (SC) molecule via the new approach, so-called repeated surface exchange of molecules (ReSEM). Combined experiments and simulations reveal that the ReSEM yields imSAMs wherein interstices between the matrix molecules are filled with the reinforcement molecules and leads to significantly enhanced breakdown voltage inaccessible by traditional pure or mixed SAMs. Thanks to this, bias-driven disappearance and inversion of rectification is unprecedentedly observed. Our work may help to overcome the shortcoming of SAM's instability and expand the functionalities.
电击穿是电子学中的一个关键问题。在分子电子学中，这一问题变得更加棘手，因为超薄分子单分子层具有精细且有缺陷的结构，并且其固有击穿电压较低，这限制了器件性能。在此，我们表明，间隙混合自组装单分子层（imSAMs）能显著提高分子尺度电子器件的电稳定性，而不会降低其功能和可靠性。通过一种新方法，即所谓的分子重复表面交换（ReSEM），空间位阻较大的基质（SCBIPY整流器）分子的自组装单分子层被一种纤细的增强分子（SC）稀释。实验和模拟相结合表明，ReSEM产生的imSAMs中，基质分子之间的间隙被增强分子填充，从而导致传统的纯自组装单分子层或混合自组装单分子层无法达到的显著提高的击穿电压。由此，前所未有的观察到了偏压驱动下整流的消失和反转。我们的工作可能有助于克服自组装单分子层不稳定的缺点，并扩展其功能。
