Domain Engineering in ReS2 by Coupling Strain during Electrochemical Exfoliation

Chemical exfoliation has been used for the fast and large‐scale production of 2D nanosheets from graphene and transition metal dichalcogenides; however, it is rarely used for domain engineering of exfoliated nanosheets. Herein, it is found that the use of large sized molecular intercalants during electrochemical intercalation induce atomic row dislocation and parallel mirror twin boundaries (MTBs) on an otherwise pristine rhenium disulfide (ReS₂) crystal, such that the exfoliated flakes possess a parallel, multi‐domain structure. These domains can be distinguished under a polarized microscope owing to the intrinsic in‐plane optical dichroic properties of ReS₂, thereby affording a way to track the number of domains introduced versus the size of the molecular intercalant during electrochemical exfoliation. Ferromagnetism is detected on the intercalated sample using large sized molecular intercalants. Density function theory suggests that these may be due to the coupled effects of lattice strain and S vacancies in the MTBs.