Structural properties of liquid exfoliated PtSe₂ nanoflakes

Session

Poster Session Two

Authors

Ilias M. Oikonomou (1, 5, 3), Danielle Douglas-Henry (1, 5), Noemi Fabiano (1, 5), Thomas Brumme (3), Zdenek Sofer (2), Thomas Heine (3, 4), Valeria Nicolosi (1, 5)

Affiliations

1. CRANN and AMBER, Trinity College Dublin
2. Dept. of Inorganic Chemistry, University of Chemistry and Technology Prague
3. TU Dresden, Chair of Theoretical Chemistry
4. Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology
5. School of Chemistry, Trinity College Dublin

Keywords

Aberration-Corrected STEM, 2D Materials, PtSe₂, Liquid-Phase Exfoliation, Density Functional Theory

Abstract text

Over the last few years, PtSe₂, a group 10 Noble-Metal Dichalcogenide (NMD), has sparked particular interest in the scientific community. It has been proven to be one of the most promising 2D materials for future industrial commercialization, with a great range of applications in sensing, photonics, and (opto)electronics.^[1] In addition to its vast applications, a recent report revealed the thermodynamical stability of different stacking orders of multilayer PtSe₂, at elevated temperatures during synthesis. This allows the modification of its electromechanical properties, due to the different electronic properties of each stacking sequence.^[2] Similarly, edges and point defects in mono- and multilayers of PtSe₂ also affect the electronic band structure, with the most characteristic example being the induced magnetism in a non-intrinsically magnetic material.^[3,4] 

 

In this study, structural modeling and comparative characterization of liquid phase exfoliated PtSe₂ is done by combining Scanning Transmission Electron Microscopy (STEM) and Density Functional Theory (DFT). 

 

2D PtSe₂ nanoflakes were produced using top-down Liquid-Phase Exfoliation (LPE). This offers an efficient, low-cost, and versatile technique to produce high-quality 2D material in large quantities.^[5] Structural and chemical characterization was done by utilizing various electron microscopy techniques. Transmission electron microscopy (TEM), Selected Area Electron Diffraction (SAED) and Energy Dispersive X-ray Spectroscopy (EDX) were performed using a FEI Titan 80-300 Thermo Fisher Scientific, fitted with a Schottky field emission gun. Operating voltage was set to 300 kV and the TEM images were recorded using a Gatan UltraScan CCD camera. Aberration-corrected STEM images were recorded with a high-angle annular dark-field (HAADF) detector using the Nion UltraSTEM operated at 200 kV, which allowed for atomic resolution structural characterization. All the experimental results were compared to first-principles calculations and HRSTEM-HAADF image simulations, in order to identify the effect of structural defects on the electronic properties and the presence of stacking phases different from the stable 1T-PtSe₂. 

 

References

[1] G. Wang, Z. Wang, N. McEvoy, P. Fan and W. J. Blau. Adv. Mater. 33, 2004070 (2021)

[2] R. Kempt, S. Lukas, O. Hartwig, M. Prechtl, A. Kuc, T. Brumme, S. Li, D. Neumaier, M. C. Lemme, G. S. Duesberg and T. Heine, Adv. Science, 9, 2201272 (2022)

[3] A. Avsar, C.-Y. Cheon, M. Pizzochero, M. Tripathi, A. Ciarrocchi, O. V. Yazyev and A. Kis, Nat. Commun. 11, 4806, (2020)

[4] J. Li, T. Joseph, M. Ghorbani-Asl, S. Kolekar, A. V. Krasheninnikov and M. Batzill, Adv. Funct. Mater. 32, 2110428, (2022)

[5] V. Nicolosi, M. Chhowalla, M. G. Kanatzidis, M. E. Strano and J. N. Coleman, Science, 340, 6139 (2013)