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An Electride as a 2D Material

Because of their loosely bound electrons, electrides offer physical properties useful in chemical synthesis and electronics. For these applications and others, nanosized electrides offer advantages, but to-date no electride has been synthesized as a nanomaterial.

Researchers in the Warren Group have demonstrated experimentally that Ca2N, a layered electride in which layers of atoms are separated by layers of a 2D electron gas, 2DEG, can be exfoliated into two-dimensional, 2D, nanosheets using liquid exfoliation. The 2D flakes are stable in a nitrogen atmosphere or in select organic solvents for at least one month.

Electron microscopy and elemental analysis reveal that the 2D flakes retain the crystal structure and stoichiometry of the parent 3D Ca2N. In addition, the 2D flakes exhibit metallic character and an optical response that agrees with DFT calculations. Together these findings suggest that the 2DEG is preserved in the 2D material. With this work, researchers bring electrides into the nanoregime and experimentally demonstrate a 2D electride, Ca2N.

This work provides the first demonstration of a conceptually new class of high surface-area, electride nanomaterials. These materials combine the high surface area of 2D materials with the exotic properties of anionic electrons. The properties of these electride nanomaterials suggest a number of applications, such as reagents or catalysts in chemical synthesis as transparent conductors or as battery electrodes.