Transition Metal Chalcogenide Tin Sulfide Nanodimensional Films Align Liquid Crystals

TL;DR

This paper demonstrates that atomically thin tin sulfide (SnS) films can serve as effective noncontact alignment layers for liquid crystals, offering comparable device performance without additional surface treatments.

Contribution

The study introduces SnS as a novel, anisotropic, atomically thin material for liquid crystal alignment, eliminating the need for surface treatments and achieving device characteristics similar to commercial options.

Findings

Threshold voltage of 0.92V

Contrast ratio better than 71:1

Rise/fall times of 80/390ms

Abstract

Transition metal chalcogenide tin sulfide (SnS) films as alternative noncontact alignment layer for liquid crystals, have been demonstrated and investigated. The SnS has an anisotropic atomic chain structure similar to black Phosphorous which causes the liquid crystal molecules to align without the need for any additional surface treatments. The high anisotropic nature of SnS promotes the alignment of the easy axis of liquid crystal molecules along the periodic atomic grooves of the SnS layer. The atomically thin SnS layers were deposited on indium tin oxide films on glass substrates, at room temperature by chemical vapor deposition. The device characteristics are comparable to those commercially available, which use photo-aligning polymer materials. We measured threshold voltage of 0.92V, anchoring energy of 1.573x10^(-6) J/m^2, contrast ratio better than 71:1 and electro-optical rise/fall times of 80/390ms, respectively for ~11 micron thick liquid crystal device as expected.