Transferred, Ultrathin Oxide Bilayers as Biofluid Barriers for Flexible Electronic Implants

Enming Song, Yoon Kyeung Lee, Rui Li, Jinghua Li, Xin Jin, Ki Jun Yu, Zhaoqian Xie, Hui Fang, Yiding Zhong, Haina Du, Jize Zhang, Guanhua Fang, Yerim Kim, Younghee Yoon, Muhammad A. Alam, Yongfeng Mei, Yonggang Huang, John A. Rogers

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The work presented here introduces a materials strategy that involves physically transferred, ultrathin layers of silicon dioxide (SiO2) thermally grown on silicon wafers and then coated with hafnium oxide (HfO2) by atomic layer deposition, as barriers that satisfy requirements for even the most challenging flexible electronic devices. Materials and physics aspects of hydrolysis and ionic transport associated with such bilayers define their performance and reliability characteristics. Systematic experimental studies and reactive diffusion modeling suggest that the HfO2 film, even with some density of pinholes, slows dissolution of the underlying SiO2 by orders of magnitude, independent of the concentration of ions in the surrounding biofluids. Accelerated tests that involve immersion in phosphate-buffered saline solution at a pH of 7.4 and under a constant electrical bias demonstrate that this bilayer barrier can also obstruct the transport of ions that would otherwise cause drifts in the operation of the electronics. Theoretical drift–diffusion modeling defines the coupling of dissolution and ion diffusion, including their effects on device lifetime. Demonstrations of such barriers with passive and active components in thin, flexible electronic test structures highlight the potential advantages for wide applications in chronic biointegrated devices.

Original languageEnglish
Article number1702284
JournalAdvanced Functional Materials
Volume28
Issue number12
DOIs
Publication statusPublished - 2018 Mar 21

All Science Journal Classification (ASJC) codes

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

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    Song, E., Lee, Y. K., Li, R., Li, J., Jin, X., Yu, K. J., Xie, Z., Fang, H., Zhong, Y., Du, H., Zhang, J., Fang, G., Kim, Y., Yoon, Y., Alam, M. A., Mei, Y., Huang, Y., & Rogers, J. A. (2018). Transferred, Ultrathin Oxide Bilayers as Biofluid Barriers for Flexible Electronic Implants. Advanced Functional Materials, 28(12), [1702284]. https://doi.org/10.1002/adfm.201702284