Solution‐Processed h‐BN Film as an Alignment Layer for Liquid Crystal Devices: Realization of a Non‐Polymer Approach for Unidirectional Alignment over Unprecedentedly Large Areas

Abstract Fabrication of liquid crystal devices heavily relies on the alignment layer providing the mandatory unidirectional orientation of the nematic molecules. Drawbacks of the traditional mechanically rubbed polymer layer have prompted to find better alternatives. However, cost‐effective methods for large‐area unidirectional alignment are still elusive. The latest attempt has been to use 2D materials deposited through the well‐known chemical vapor deposition process, invariably inviting all the associated complexities including high‐temperature processing, cumbersome transfer onto the required substrate, etc. Most importantly, the achieved domain size over which the nematic molecules exhibit unidirectional planar orientation, has been too small (sub‐mm 2 ) for employable devices. Here, the authors present a room temperature solution process for obtaining h‐BN dispersion and directly depositing it as a film on the device substrate using the electrophoretic technique. The achieved layer far surpasses the size limitation mentioned above, resulting in unidirectional LC orientation over at least 4 cm 2 and promising for much larger areas with the electrical and electro‐optic switching performance being comparable to an industry‐standard device. The success of this simpler method establishes 2D materials as strong contenders for achieving non‐contact LC alignment and, in a broader sense, brings the much‐needed impetus to explore new horizons for solution‐processed devices.