Modelling the structural disorder in trigonal‐prismatic coordinated transition metal dichalcogenides. Issue 2 (30th March 2023)

• Record Type: Journal Article
• Authors: Ursi, Federica; Virga, Simone; Pipitone, Candida; Sanson, Alessandra; Longo, Alessandro; Giannici, Francesco; Martorana, Antonino
• Is Part Of: Journal of applied crystallography. Volume 56:Issue 2(2023)
• Page Start: 502
• Page End: 509
• Publication Date: 2023-03-30
• Subjects: chalcogenides -- disorder -- stochastic modelling -- X‐ray diffraction; Crystallography -- Periodicals; 548.05
• DOI: 10.1107/S1600576723001589
• Languages: English
• ISSNs: 0021-8898

Abstract

Abstract : The structural disorder in trigonal‐prismatic coordinated transition metal layered dichalcogenides is investigated. The structural model taking into account stacking faults, correlated displacement of atoms and average crystallite size is assessed by fitting to the X‐ray diffraction pattern of an exfoliated–restacked MoS2 sample. Abstract : Trigonal‐prismatic coordinated transition metal dichalcogenides (TMDCs) are formed from stacked (chalcogen)–(transition metal)–(chalcogen) triple layers, where the chemical bond is covalent within the triple layers and van der Waals (vdW) forces are effective between the layers. Bonding is at the origin of the great interest in these compounds, which are used as 2D materials in applications such as catalysis, electronics, photoelectronics, sensors, batteries and thermoelectricity. This paper addresses the issue of modelling the structural disorder in multilayer TMDCs. The structural model takes into account stacking faults, correlated displacement of atoms and average crystallite size/shape, and is assessed by simulation of the X‐ray diffraction pattern and fitting to the experimental data relative to a powdered sample of MoS2 exfoliated and restacked via lithiation. From fitting, an average crystallite size of about 50 Å, nearly spherical crystallites and a definite probability of deviation from the fully eclipsed atomic arrangement present in the ordered structure are determined. The increased interlayer distance and correlated intralayer and interlayer atomic displacement are attributed to the presence of lithium intercalated in the vdW gap between triple layers (Li/Mo molar ratio of about 0.06). The model holds for the whole class of trigonal‐prismatic coordinated TMDCs, and is suitably flexible to take into account different preparation routes.