The covalent functionalization of few-layered MoTe2 thin films with iodonium salts

• Published in: Materials today chemistry 2022-06, Vol.24, p.100846, Article 100846
• Main Authors: Guselnikova, O., Fraser, J.P., Soldatova, N., Sviridova, E., Ivanov, A., Rodriguez, R., Ganin, A.Y., Postnikov, P.
• Format: Article
• Language: English
• Subjects: 2D materials; Chemical Vapor Deposition; Iodonium salt; Surface chemistry; Transition-metal dichalcogenides; X-Ray Photoelectron Spectroscopy
• ISSN: 2468-5194; 2468-5194
• DOI: 10.1016/j.mtchem.2022.100846

Covalent functionalization of 2D materials provides a tailored approach towards tuning of their chemical, optical, and electronic properties making the search for new ways to graft small molecules important. Herein, the reaction with (3,5-bis(trifluoromethyl)phenyl)iodonium salt is revealed as an effective strategy for functionalization of MoTe2 thin films. Upon decomposition of the salt, the generated radicals graft covalently as aryl-(CF3)2 groups at the surface of both metallic (1T’) and semiconducting (2H) polymorphs of MoTe2. Remarkably, the reactivity of the salt is governed by the electronic structure of the given polymorph. While the functionalization of the metallic MoTe2 occurs spontaneously, the semiconducting MoTe2 requires activation by light. The reaction proceeds with the elimination of oxide from the original films yielding the functionalized products that remain protected in ambient conditions, presenting a viable solution to the ageing of MoTe2 in air. •Covalent functionalization using iodonium slats is confirmed on MoTe2 films.•Homolysis of C–I bons in iodonium salts is governed by the nature of MoTe2 polymorph.•Modification enables the elimination of oxides from the surface of the films.•Intramolecular excitation of iodonium salts is the key step in the aryl radical generation.•Surfaces of MoTe2 films demonstrate remarkable stability against oxidation upon functionalisation.