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

Cencen Wei, Abhijit Roy, Manoj Tripathi, Adel K.A. Aljarid, Jonathan P. Salvage, S. Mark Roe, Raul Arenal, Conor S. Boland

Research output: Contribution to journalArticlepeer-review


Spectrally inactive, electrically insulating, and chemically inert are adjectives broadly used to describe phyllosilicate minerals like mica and chlorite. Here, the above is disproved by demonstrating aqueous suspensions of liquid exfoliated nanosheets from five bulk mica types and chlorite schist. Nanosheet quality is 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 is observed. When analyzing the high‐yield suspensions (≈1 mg mL−1) through UV–vis spectroscopy, all phyllosilicates present bandgap (Eg) narrowing from ≈7 eV in the bulk to ≈4 eV for monolayers. Unusually, the bandgap is inversely proportional to the areal size (A) of the nanosheets, measured via atomic force microscopy. Due to an unrecorded quantum confinement effect, nanosheet electronic properties scale toward semiconducting behavior (bandgap ≈3 eV) as nanosheet area increases. Furthermore, modeling X‐ray diffraction spectra shows that the root cause of the initial bandgap narrowing is lattice relaxation. Finally, with their broad range of isomorphically substituted ions, phyllosilicate nanosheets show remarkable catalytic properties for hydrogen production.
Original languageEnglish
Number of pages29
JournalAdvanced Materials
Issue number39
Publication statusPublished - 19 Jun 2023

Bibliographical note

Funding Information:
The authors acknowledge funding through the University of Sussex Strategic Develop Fund and the Saudi Arabian Cultural Bureau. R.A. acknowledges funding from the Spanish MCIN (project grant PID2019‐104739GB‐100/AEI/10.13039/501100011033), the Government of Aragon (project DGA E13‐20R), and the European Union H2020 program “ESTEEM3” (823717).

Publisher Copyright:
© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.


  • Mechanical Engineering
  • Mechanics of Materials
  • General Materials Science


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