Exfoliation of Calcium Germanide by Alkyl Halides

Two-dimensional materials are at the forefront of material research in the past decade. Besides graphene, there exist large groups of its heavier analogues, silicon- and germanium-based two-dimensional materials, which are much less explored. Methods of synthesis of germanene derivatives are based on chemical exfoliation of Zintl phase precursors. Here we report a novel effective and flexible method for synthesis of alkylated derivatives of germanene by phase transfer assisted exfoliation of calcium germanide. We demonstrate the universality of the reported method and its broad application in synthesis of various germanene derivatives. The developed method allows precise control over the chemical composition and optical properties of germanene derivatives.