Hwang Jinhyun, Park Jisang, Choi Jinhyeok, Lee Taeksang, Lee Hyo Chan, Cho Kilwon
Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
Department of Mechanical Engineering, Myongji University, Yongin, 17058, Republic of Korea.
Adv Sci (Weinh). 2024 May;11(19):e2400598. doi: 10.1002/advs.202400598. Epub 2024 Mar 13.
Graphene is used as a growth template for van der Waals epitaxy of organic semiconductor (OSC) thin films. During the synthesis and transfer of chemical-vapor-deposited graphene on a target substrate, local inhomogeneities in the graphene-in particular, a nonuniform strain field in the graphene template-can easily form, causing poor morphology and crystallinity of the OSC thin films. Moreover, a strain field in graphene introduces a pseudo-electric field in the graphene. Here, the study investigates how the strain and strain-induced pseudo-electric field of a graphene template affect the self-assembly of π-conjugated organic molecules on it. Periodically strained graphene templates are fabricated by transferring graphene onto an array of nanospheres and then analyzed the growth and nucleation behavior of C thin films on the strained graphene templates. Both experiments and a numerical simulation demonstrated that strained graphene reduced the desorption energy between the graphene and the C molecules and thereby suppressed both nucleation and growth of the C. A mechanism is proposed in which the strain-induced pseudo-electric field in graphene modulates the binding energy of organic molecules on the graphene.
石墨烯被用作有机半导体（OSC）薄膜范德华外延生长的模板。在化学气相沉积石墨烯在目标衬底上的合成和转移过程中，石墨烯中的局部不均匀性——特别是石墨烯模板中的非均匀应变场——很容易形成，导致OSC薄膜的形貌和结晶性较差。此外，石墨烯中的应变场会在石墨烯中引入一个伪电场。在此，该研究调查了石墨烯模板的应变和应变诱导的伪电场如何影响其上π共轭有机分子的自组装。通过将石墨烯转移到纳米球阵列上制备周期性应变的石墨烯模板，然后分析C薄膜在应变石墨烯模板上的生长和成核行为。实验和数值模拟均表明，应变石墨烯降低了石墨烯与C分子之间的解吸能，从而抑制了C的成核和生长。提出了一种机制，其中石墨烯中应变诱导的伪电场调节了有机分子在石墨烯上的结合能。
