The effect of film microstructures on cracking of transparent conductive oxide (TCO) coatings on polymer substrates

Jin Woo Park, Gyeom Kim, Seung Ho Lee, Eun Hye Kim, Geon Hwan Lee

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

We investigate the effects of film microstructures such as crystallinity and surface roughness on cracking of TCO coated on polymer substrates. Indium tin oxide (ITO), which is the most extensively used TCO for electrodes in flexible electronics, is sputter-deposited on polyethylene terephthalate (PET). Varying thickness (tf) and deposition condition, amorphous ITO (a-ITO) with different surface roughness (Rrms) and a partially crystallized ITO with similar Rrms to a-ITO of the same tf are coated on PET. Cracking in ITO under tension is analyzed by uniaxial tension test. The mode of cracking and the fracture strength are related to the crystallinity and Rrms of ITO analyzed by high resolution transmission electron microscopy (HR TEM) and atomic force microscopy (AFM), respectively. Our experimental results reveal that the strength of ITO is significantly improved with crystallinity. The important effect of Rrms on cracking is also clearly revealed. In a-ITO, fracture strength is decreased almost linearly with Rrms that increases with tf. In addition, cracks are always initiated and propagated along the valleys between protrusions on the surface regardless of crystallinity. Based on our experimental results, a low temperature deposition condition to obtain ITO with a high level of functional and mechanical properties is proposed.

Original languageEnglish
Pages (from-to)915-921
Number of pages7
JournalSurface and Coatings Technology
Volume205
Issue number3
DOIs
Publication statusPublished - 2010 Oct

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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