Molecular self-alignment on InO/Ag composite film with unidirectional solution coating process

Abstract

Uniform alignment of liquid crystals (LCs) on indium oxide/silver (InO/Ag) composite films is introduced in this work. The films were prepared by a solution-processing method via brush coating, and the Ag concentrations were adjusted to 0, 10, and 20 wt%. X-ray photoelectron spectroscopy was used to confirm the formation of the InO/Ag composite films. Then, scanning electron microscopy and X-ray diffraction were used to reveal the amorphous and anisotropic surface structure generated by the movement of the brush hairs during solution coating. This anisotropic surface induced uniform orientation of the LCs. The LC alignment states were also confirmed by polarized optical microscopy measurements. The InO/Ag composite films exhibited appropriate optical transmittance for the LC electronic device application. Moreover, LC cells manufactured using the InO/Ag composite films demonstrated improved LC polar anchoring energy, which is a critical parameter related to image stability. The cells also demonstrated reduced residual charge, which is related to the image sticking phenomenon. Consequently, we anticipate that the proposed InO/Ag composite films can serve as useful alternative LC alignment layers in LC electronic devices.

Graphical Abstract