Highly Flexible and Transparent Ag Nanowire Electrode Encapsulated with Ultra-Thin Al2O3: Thermal, Ambient, and Mechanical Stabilities

Eunha Lee,Hyoungsub Kim,Hyangsook Lee,Youngseo An,Yong-Hoon Kim,Stefan Becker,Byungil Hwang

doi:10.1038/srep41336

Eunha Lee, Hyoungsub Kim + Show 5 more

Open Access

https://doi.org/10.1038/srep41336

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Journal: Scientific Reports	Publication Date: Jan 27, 2017
Citations: 86	License type: open-access

Affiliation: Samsung (South Korea), Sungkyunkwan University

Abstract

There is an increasing demand in the flexible electronics industry for highly robust flexible/transparent conductors that can withstand high temperatures and corrosive environments. In this work, outstanding thermal and ambient stability is demonstrated for a highly transparent Ag nanowire electrode with a low electrical resistivity, by encapsulating it with an ultra-thin Al2O3 film (around 5.3 nm) via low-temperature (100 °C) atomic layer deposition. The Al2O3-encapsulated Ag nanowire (Al2O3/Ag) electrodes are stable even after annealing at 380 °C for 100 min and maintain their electrical and optical properties. The Al2O3 encapsulation layer also effectively blocks the permeation of H2O molecules and thereby enhances the ambient stability to greater than 1,080 h in an atmosphere with a relative humidity of 85% at 85 °C. Results from the cyclic bending test of up to 500,000 cycles (under an effective strain of 2.5%) confirm that the Al2O3/Ag nanowire electrode has a superior mechanical reliability to that of the conventional indium tin oxide film electrode. Moreover, the Al2O3 encapsulation significantly improves the mechanical durability of the Ag nanowire electrode, as confirmed by performing wiping tests using isopropyl alcohol.

Highlights

To resolve the issues concerning thermal and ambient stability, several studies have proposed the encapsulation of the Ag nanowire electrode by a material with a high melting temperature[1,2,3,14,15,16]
We report the detailed characterization results of a highly robust Ag nanowire transparent electrode encapsulated using an ultrathin Al2O3 layer (Al2O3/Ag nanowire electrode) fabricated by a simple low-temperature atomic layer deposition (ALD) process, especially focusing on its thermal, ambient, and mechanical stabilities
Excellent thermal and ambient stabilities were achieved for Ag nanowire electrodes encapsulated with an ultra-thin Al2O3 layer (~5.3 nm) coated by low-temperature (100 °C) ALD

Summary

Introduction

To resolve the issues concerning thermal and ambient stability, several studies have proposed the encapsulation of the Ag nanowire electrode by a material with a high melting temperature[1,2,3,14,15,16]. A couple of research groups adopted a low-temperature atomic layer deposition (ALD) process to coat conformal encapsulation layers, www.nature.com/scientificreports/. Such as ZnO and Al2O3, on Ag nanowires[14,15,16]. We report the detailed characterization results of a highly robust Ag nanowire transparent electrode encapsulated using an ultrathin Al2O3 layer (Al2O3/Ag nanowire electrode) fabricated by a simple low-temperature ALD process, especially focusing on its thermal, ambient, and mechanical stabilities. The Al2O3/Ag nanowire electrode was mechanically robust and stable under conditions of severe bending fatigue tests and wiping tests using isopropyl alcohol (IPA), which demonstrates its applicability in flexible and stretchable electronics experiencing harsh fabrication or operation conditions

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