Large band gap of insulator clay nanosheets*

Two dimensional materials possess many unique properties. From the electronic structural point of view, one can find conductive, semiconducting and insulating single nanosheets. Here we report a wide band gap insulator (band gap energy up to 7.1-8.2 eV) nanosheets obtained by delamination of synthetic fluorohectorite clay testifying these nanosheets to be one of the largest band gap insulators in the world. The band gap has been determined by electron energy loss spectroscopy in a high resolution transmission electron microscope. Fluorohectorite clay 1 nm thick single nanosheets can be synthetized with high-aspect ratio and lateral dimensions up to dozens of microns. This property renders the synthetic fluorohectorite nanosheets promising candidates for practical applications in electronic devices, serving as insulating nanosheets for deposition of graphene and various (semi)conductive 2D materials by self-assembly.