In this study, Al2O3/alucone nanolayered composites were studied as the overcoating for Ag nanowire electrodes with the aim of improving their mechanical reliability. Ultrathin and conformal Al2O3/alucone nanolayered composites with different layer spacings were formed on Ag nanowire electrodes via molecular layer deposition. To evaluate the effect of the different nanolayered composite overcoatings with the different layer spacing on the mechanical reliability of Ag nanowire electrodes, bending fatigue tests were performed on the specimens for up to 300,000 cycles while monitoring their resistance in situ. Ag nanowire electrodes with the nanolayered composite overcoating exhibited considerably smaller increases in resistance under bending fatigue, as compared to those with a single Al2O3 layer. In the nanolayered composites, the increase in resistance was further reduced as the layer spacing was decreased. Microstructural analysis confirmed that the density of propagated cracks in the overcoating layers was lower in the nanolayered composites compared to the single Al2O3 layer, resulting in a smaller increase in the resistance of the nanolayered composites. A finite-element method simulation of the bending of a single Al2O3 layer and nanolayered composites, which were designed to match the characteristics of our experimentally tested samples, indicated stress relaxation at the interfaces of the alucone layer, which strengthens the mechanical reliability of the nanolayered composites.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT) (No. NRF-2019K1A3A1A25000230) and by the Korea Basic Science Institute under the R&D program (Project No. C030440) supervised by the Ministry of Science and ICT. P.M. acknowledges support from the Ministry of Foreign Affairs and International Cooperation of Italy (MAECI) through the “Development of a cost-effective wearable metal nanowire-based chip sensor for optical monitoring of metabolites in sweat” DESWEAT Project (n° KR19GR08) funded within the framework of the Executive Programme of Scientific and Technological Cooperation between the Italian Republic and the Korean Republic 2019–2021.