Large bandgap insulating superior clay nanosheets

Abstract

One can find conductive, semiconducting, and insulating single nanosheets with unique electronic properties that are tied to their two-dimensional (2D) structure. Here, we report on wide-bandgap 2D insulator nanosheets obtained by delamination of a synthetic 2D fluorohectorite clay mineral showing one of the largest bandgap insulators in the world. The bandgap was determined experimentally to be up to 7.1–8.2 eV measured by electron energy-loss spectroscopy in a high-resolution transmission electron microscope. The experimental data were supported by DFT calculations giving a bandgap of 5.5 eV. The single fluorohectorite clay crystalline nanosheets are 0.95-nm, and they can be synthetized with high-aspect ratios and lateral dimensions up to dozens of microns. These properties render these nanosheets promising candidates for practical applications in manually assembled or self-assembled electronic heterostructures, potentially serving as insulating nanosheets in graphene or various (semi)conductive 2D material-based devices.