Molecular Routes to Two-Dimensional Metal Dichalcogenides MX2 (M = Mo, W; X = S, Se)

Veronika Brune; Corinna Hegemann; Sanjay Mathur

doi:10.1021/acs.inorgchem.9b01084

Molecular Routes to Two-Dimensional Metal Dichalcogenides MX₂ (M = Mo, W; X = S, Se)

Inorg Chem. 2019 Aug 5;58(15):9922-9934. doi: 10.1021/acs.inorgchem.9b01084. Epub 2019 Jul 16.

Authors

Veronika Brune¹, Corinna Hegemann¹, Sanjay Mathur¹

Affiliation

¹ Institute of Inorganic Chemistry , University of Cologne , Greinstraße 6 , D-50939 Cologne , Germany.

PMID: 31310512
DOI: 10.1021/acs.inorgchem.9b01084

Abstract

New synthetic access to two-dimensional transition metal dichalcogenides (TMDCs) is highly desired to exploit their extraordinary semiconducting and optoelectronic properties for practical applications. We introduce here an entirely novel class of molecular precursors, [M^IV(XEtN(Me)EtX)₂] (M^IV = Mo^IV, W^IV, X = S, Se), enabling chemical vapor deposition of TMDC thin films. Molybdenum and tungsten complexes of dianionic tridentate pincer-type ligands (HXEt)₂NR (R = methyl, tert-butyl, phenyl) produced air-stable monomeric dichalcogenide complexes, [W(SEtN(Me)EtS)₂] and [Mo(SEtN(Me)EtS)₂], displaying W and Mo centers in an octahedral environment of 4 S and 2 N donor atoms. Owing to their remarkable volatility and clean thermal decomposition, both Mo and W complexes, when used in the chemical vapor deposition (CVD) process, produced crystalline MoS₂ and WS₂ thin films. X-ray diffraction analysis and atomic-scale imaging confirmed the phase purity and 2D structural characteristics of MoS₂ and WS₂ films. The new set of ligands presented in this work open ups convenient access to a scalable and precursor-based synthesis of 2D transition metal dichalcogenides.