Liquid crystal aligning capabilities on surface-reformed indium-doped zinc oxide films via ion-beam exposure

Ju Hwan Lee, Eun Mi Kim, Gi Seok Heo, Hae Chang Jeong, Dong Hyun Kim, Dong Wook Lee, Jeong Min Han, Tae Wan Kim, Dae Shik Seo

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We investigated the characteristics of a solution-processed indium-doped zinc oxide (In:ZnO) film formed via ion-beam (IB) irradiation as a liquid crystal (LC) alignment layer. The In:ZnO film was deposited using solution processing and cured at various temperatures. Uniform LC alignment was observed at all curing temperatures in cross-polarised optical microscopy images. A regular pre-tilt angle supported these results and showed homogeneous LC alignment. Several surface analyses were conducted to evaluate the effect of IB irradiation on the In:ZnO film surface. X-ray diffraction analysis showed an amorphous structure both before and after IB irradiation, and physical surface reformation was observed using atomic force microscopy. Root mean square surface roughness was reduced and a smooth surface was achieved after IB irradiation. X-ray photoelectron spectroscopy was used to detect chemical surface reformation. It was found that the IB irradiation broke the metal-oxide bonds and increased the occurrence of oxygen vacancies, which affected the van der Waals forces between the LC molecules and the In:ZnO film surface. Electrical performance was observed to identify the possibility of using the In:ZnO film in LC applications. Enhanced electro-optical performance was measured and zero residual DC voltage which was verified using a capacitance-voltage curve was achieved.

Original languageEnglish
Pages (from-to)1137-1146
Number of pages10
JournalLiquid Crystals
Volume45
Issue number8
DOIs
Publication statusPublished - 2018 Jun 21

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Lee, J. H., Kim, E. M., Heo, G. S., Jeong, H. C., Kim, D. H., Lee, D. W., Han, J. M., Kim, T. W., & Seo, D. S. (2018). Liquid crystal aligning capabilities on surface-reformed indium-doped zinc oxide films via ion-beam exposure. Liquid Crystals, 45(8), 1137-1146. https://doi.org/10.1080/02678292.2017.1416503