Atomic layer deposited films of Al2O3 on fluorine-doped tin oxide electrodes: stability and barrier properties

Hana Krýsová; Michael Neumann-Spallart; Hana Tarábková; Pavel Janda; Ladislav Kavan; Josef Krýsa

doi:10.3762/bjnano.12.2

Atomic layer deposited films of Al₂O₃ on fluorine-doped tin oxide electrodes: stability and barrier properties

Beilstein J Nanotechnol. 2021 Jan 5:12:24-34. doi: 10.3762/bjnano.12.2. eCollection 2021.

Authors

Hana Krýsová¹, Michael Neumann-Spallart², Hana Tarábková¹, Pavel Janda¹, Ladislav Kavan¹, Josef Krýsa²

Affiliations

¹ J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
² Department of Inorganic Technology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic.

Abstract

Al₂O₃ layers were deposited onto electrodes by atomic layer deposition. Solubility and electron-transport blocking were tested. Films deposited onto fluorine-doped tin oxide (FTO, F:SnO₂/glass) substrates blocked electron transfer to redox couples (ferricyanide/ferrocyanide) in aqueous media. However, these films were rapidly dissolved in 1 M NaOH (≈100 nm/h). The dissolution was slower in 1 M H₂SO₄ (1 nm/h) but after 24 h the blocking behaviour was entirely lost. The optimal stability was reached at pH 7.2 where no changes were found up to 24 h and even after 168 h of exposure the changes in the blocking behaviour were still minimal. This behaviour was also observed for protection against direct reduction of FTO.

Keywords: Al2O3; FTO; atomic layer deposition (ALD); barrier properties; corrosion; electrochemistry.

Grants and funding

The authors would like to thank the Czech Science Foundation (project number 20-11635S) for financial support and acknowledge the assistance provided by the Research Infrastructure NanoEnviCz, supported by the Ministry of Education, Youth and Sports of the Czech Republic under Project No. LM2018124.