Figure 1.

SEM comparison of metal diboride nanoplatelets made under ambient and inert conditions. (A) Hexagonal AlB₂-type crystal structure, typical for layered metal diborides such as MgB₂. Layers of negatively charged boron sheets (represented by a green hexagonal lattice) are sandwiched between Mg²⁺ ions (black spheres and square lattice). (B, C) Representative SEM image (B) and size distribution of MgB₂ crystallites (C) in the powder used as a starting material. (D) Photograph of the setup used for exfoliation under ambient conditions. (E, F) Scanning electron microscopy (SEM) image showing an overview of drop cast nanosheets after exfoliation (E) using the setup shown in panel D and the corresponding size distribution of MgB₂ nanosheets determined from SEM imaging (F). (G) Photograph of the setup used for exfoliation under inert conditions. (H, I) SEM image showing an overview of drop cast nanosheets after exfoliation (H) using the setup shown in panel G and corresponding size distribution of MgB₂ nanosheets determined from SEM imaging (I).