Alignment Relation between a Nematic Liquid Crystal and ReS₂ Nanosheets: Implications for Anisotropic Optoelectronic Applications

Rhenium disulfide (ReS2), a two-dimensional (2D) semiconductor, exhibits unique anisotropic properties rarely found in other 2D materials. This study investigates the alignment characteristics of nematic liquid crystals on ReS2 nanosheet using optical texture analysis, transmission measurements, and Raman scattering techniques. For the b→andc→, crystal basis vectors of ReS2, the director (n^0) aligned along the easy axis satisfies equations, n^0·(c→×b→)>0 and n^0·b→=|b→|cos(θ) > 0 with θ = 15°. Both polar and azimuthal anchoring strengths were found to be very weak, with extrapolation lengths on the order of several micrometers. Additionally, the orientation of the ReS2 nanosheets suspended in the nematic liquid crystal is effectively controlled through electric field application and director manipulation. The ability to control the orientation of ReS2 nanosheets through several methods suggests that the anisotropic properties of ReS2 can be effectively tuned to different values for switching applications. This capability opens up possibilities for leveraging the unique directional characteristics of ReS2 in devices that require precise orientation-dependent control.