Exotic Electronic Properties of 2d Nanosheets Isolated from Liquid Phase Exfoliated Phyllosilicate Minerals.

Spectrally inactive, electrically insulating, chemically inert are adjectives broadly used to describe phyllosilicate minerals like mica and chlorite. Here, w e disprove the above by demonstrating aqueous suspensions of liquid exfoliated nanosheets from five bulk mica types and chlorite schist. Nanosheet quality wa s confirmed via transmission electron and X-ray photoelectron spectroscopies, as well as electron diffraction. Through Raman spectroscopy, a previously unreported size and layer dependent spectral fingerprint w as observed. When analysing the high yield suspensions (∼1 mg/mL) through UV-Visible spectroscopy, all phyllosilicates presented bandgap narrowing from ∼7 eV in the bulk to ∼4 eV for monolayers. Unusually, bandgap w as inversely proportional to the areal size of the nanosheets, measured via Atomic Force Microscopy. Due to an unrecorded quantum confinement effect, nanosheet electronic properties scaled towards semiconducting behaviour (bandgap ∼3 eV) as nanosheet area increased. Furthermore, modelling X-ray diffraction spectra, the root cause of the initial bandgap narrowing wa s lattice relaxation. Finally, with their broad range of isomorphically substituted ions, phyllosilicate nanosheets showed remarkable catalytic properties for hydrogen production. This article is protected by copyright. All rights reserved.