Graphdiyne (GDY) is an ordered two-dimensional (2D) carbon allotrope comprising sp- and sp²-hybridized carbon atoms with high degrees of π-conjugation, which features a natural band gap and superior electric properties. However, the synthesis of one- or few-layer GDY remains challenging because of the free rotation around alkyne-aryl single bonds and the lack of thickness control. We report the facile synthesis of an ultrathin single-crystalline GDY film on graphene through a solution-phase van der Waals epitaxial strategy. The weak admolecule-substrate interaction at the heterojunction drastically relaxes the large lattice mismatch between GDY and graphene. It allows the fast in-plane coupling of admolecules and slow out-of-plane growth toward the formation of an incommensurately stacked heterostructure, which is composed of single-layer graphene and few-layer ABC-stacked GDY, as directly observed by electron microscopy and identified from Raman fingerprints. This study provides a general route not only to the bottom-up synthesis of intriguing 2D acetylenic carbon allotropes but also to the device fabrication for the direct measurement of their intrinsic electrical, mechanical, and thermal properties.

中文翻译：

---

通过溶液相范德华外延在石墨烯上形成超薄石墨二炔薄膜。

Graphdiyne（GDY）是包含sp-和sp ²的有序二维（2D）碳同素异形体-具有高π共轭度的杂化碳原子，具有自然的带隙和优异的电性能。然而，由于围绕炔基-芳基单键的自由旋转和缺乏厚度控制，一层或几层GDY的合成仍然具有挑战性。我们报告了通过溶液相范德华斯外延策略在石墨烯上的超薄单晶GDY膜的简便合成。异质结处的弱分子与底物之间的相互作用极大地缓解了GDY与石墨烯之间的大晶格失配。它允许分子的快速面内耦合和缓慢的面外生长，从而形成由单层石墨烯和几层ABC堆叠的GDY组成的不相称的堆叠异质结构，如通过电子显微镜直接观察并从拉曼指纹图谱中鉴定。这项研究不仅为引人入胜的2D炔属碳同素异形体的自下而上的合成提供了一条通用途径，而且还为直接测量其固有的电，机械和热性能的器件制造提供了一条通用途径。