Highly robust Ag nanowire flexible transparent electrode with UV-curable polyurethane-based overcoating layer

• Published in: Materials & design 2017-09, Vol.129, p.180-185
• Main Authors: Hwang, Byungil, An, Chee-Hong, Becker, Stefan
• Format: Article
• Language: English
• Subjects: Chemical stability; Mechanical reliability; Overcoating; Patterning; Silver nanowire
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2017.05.042

In this study, we explored a novel material package, which adopted a UV-curable Raygloss® as an overcoating layer on Ag nanowire network; successfully solved the existing stability issues of Ag nanowire electrodes. The mechanical stabilities were remarkably enhanced by adopting Raygloss® as an overcoating layer that showed no degradation in optical or electrical properties after being scratched 100 times or after being wiped 60 times using isopropyl alcohol. Furthermore, the Raygloss® coated Ag nanowire electrodes was highly reliable without showing increase in resistance even after 300,000cycles of bending, while the bare Ag nanowire electrodes showed 23.6% increase in resistance. Furthermore, the overcoating with Raygloss® protected the Ag nanowires from oxidation; they remained stable even after 120h at 85°C. Moreover, the optical transmittance of the Ag nanowire electrodes was confirmed to be enhanced by the Raygloss® coating since the refractive index of Raygloss® is between that of air and the substrate. Lastly, 10μm scales of Ag nanowire patterns with Raygloss® overcoating layer was demonstrated by selectively curing the Raygloss® with a shadow mask, followed by simple removal of the Ag nanowires in the uncured region using sonication in isopropyl alcohol. [Display omitted] •The UV-curable polyurethane-based overcoating enhanced the resistance of Ag nanowire electrodes to scratching and wiping.•The reliability under bendings was also enhanced, which showed no resistance increase after the 300,000 cycles of bending.•The overcoating could efficiently suppress the surface oxidation of Ag nanowires during the exposure to air for 120h.•The optical transmittance was confirmed to be enhanced by the overcoating due to its intermediate refractive index, ~1.54.•The Ag nanowire electrodes could be patterned without chemical etching by using the photo-patternable overcoating layer.