Surface modified solution-derived nickel oxide film via ion-beam irradiation as a liquid crystal alignment layer

Ju Hwan Lee, Jonghoon Won, Hae Chang Jeong, Dong Hyun Kim, Dong Wook Lee, In Ho Song, Byeong Yun Oh, Jeong Min Han, Dai Hyun Kim, Dae Shik Seo

Research output: Contribution to journalArticle

Abstract

In this article, we demonstrate the liquid crystal (LC) alignment characteristics of solution-derived nickel oxide (NiO) film modified with ion-beam (IB) irradiation. Cross-polarized optical microscopy and pretilt angle measurements verified that uniform LC alignment was achieved using the NiO film as an alignment layer regardless of IB incidence angle. Contact angle measurements revealed that all of the NiO films had a deionized water contact angle below 90°, which indicates that they had hydrophilic surfaces that had an effect on the homogeneous LC alignment. Atomic force microscopy was conducted to determine the physical surface modification due to the IB irradiation, which showed that it reduced the size of the surface grains with agglomerations depending on the surface tilt from the IB incidence angle. Furthermore, microgroove structures strongly related to uniform LC alignment were observed after IB irradiation. Chemical surface modification was investigated via an X-ray photoelectron spectroscopy analysis which revealed that IB irradiation modified the chemical bonds in the NiO film, and this affected the LC alignment state. Thus, these results indicate that using NiO film exposed to IB irradiation as an alignment layer is a suitable method for LC applications.

Original languageEnglish
Pages (from-to)806-815
Number of pages10
JournalJournal of the Society for Information Display
Volume27
Issue number12
DOIs
Publication statusPublished - 2019 Dec 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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