Covalent crystals such as diamonds are a class of fascinating materials that are challenging to fabricate in the form of thin films. This is because spatial kinetic control of bond formation is required to create covalently bonded crystal films. Directional crystal growth is commonly achieved by chemical vapor deposition, an approach that is hampered by technical complexity and associated high cost. Here we report on a liquid-liquid interfacial approach based on physical-organic considerations to synthesize an ultrathin covalent crystal film. By distributing reactants into separate phases using hydrophobicity, the chemical reaction is confined to an interface that orients the crystal growth. A molecular-smooth interface combined with in-plane isotropic conditions enables the synthesis of films on a centimeter size scale with a uniform thickness of 13 nm. The film exhibits considerable mechanical robustness enabling a free-standing length of 37 µm, as well as a clearly anisotropic chemical structure and crystal lattice alignment.

诸如钻石之类的共价晶体是一类迷人的材料，很难以薄膜形式制造。这是因为需要对键形成进行空间动力学控制以创建共价键合的晶体薄膜。定向晶体生长通常通过化学气相沉积实现，这种方法受到技术复杂性和相关高成本的阻碍。在这里，我们报告了一种基于物理-有机因素的液-液界面方法来合成超薄共价晶体薄膜。通过使用疏水性将反应物分配到不同的相中，化学反应被限制在定向晶体生长的界面上。分子光滑的界面与面内各向同性条件相结合，可以合成厚度为 13 nm 的厘米级薄膜。该薄膜表现出相当大的机械强度，可实现 37 µm 的独立长度，以及明显的各向异性化学结构和晶格排列。