Effect of Mechanical Properties of Substrates on Flexibility of Ag Nanowire Electrodes under a Large Number of Bending Cycles

Tae Gwang Yun,Byungil Hwang

doi:10.3390/coatings11091074

Tae Gwang Yun, Byungil Hwang

Open Access

https://doi.org/10.3390/coatings11091074

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Journal: Coatings	Publication Date: Sep 6, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: Myongji University, Chung-Ang University

Abstract

Ag nanowire electrodes have attracted considerable attention because of their potential applications in next-generation flexible electronics. However, there is a paucity of studies on the mechanical properties of Ag nanowire electrodes subjected to a large number of bending cycles. In this study, the effects of the substrate on the mechanical behavior of Ag nanowire electrodes were studied for a high bending frequency. The mechanical reliability of the Ag nanowire electrodes fabricated on a polyethylene terephthalate (PET) substrate was better than that for a polyimide (PI) substrate; the increase in the resistance of the PET-based Ag nanowire electrode was 1.07%, while that of the PI-based one was 1.23%. Nanoindentation tests showed that the elastic modulus of PI was larger than that of PET. This resulted in a lower bending strain on PET-based Ag nanowire electrodes compared to those on PI-based ones, because of the smaller distance from the neutral plane of the PET-based system. Our study showed that the mechanical properties of the substrate influenced the strain imposed on the thin layer on the substrates, which, in turn, determines the mechanical reliability of the thin-layer/substrate multilayer system.

Highlights

Our study showed that the mechanical properties of the substrate influenced the strain imposed on the thin layer on the substrates, which, in turn, determines the mechanical reliability of the thin-layer/substrate multilayer system
Technological advances in flexible electronics require reliable, flexible transparent electrodes that are stable under severe deformation, when subjected to a large number of bending cycles [1,2,3]
The mechanical brittleness of Indium tin oxide (ITO) limits its use in flexible electronics [7,8]

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Technological advances in flexible electronics require reliable, flexible transparent electrodes that are stable under severe deformation, when subjected to a large number of bending cycles [1,2,3]. The mechanical brittleness of ITO limits its use in flexible electronics [7,8]. To confirm the mechanical stability, 100,000 bending cycles, under a 5 mm radius, were imposed on the electrodes, which resulted in a negligible change in resistance during bending. There have been several studies on Ag nanowire transparent electrodes, as indicated in the examples, most of them were performed by imposing only a limited number of bending cycles, which makes it difficult to delineate the mechanical behavior of the Ag nanowire electrodes under bending. Polyimide (PI) and PET, which are the two most widely used substrates, were used to study the effect of the substrates on the deformation behavior of Ag nanowire electrodes

Sample Preparation

Characterization

Results

Results and Discussion mechanical reliability under increase of only Ag

Schematic of thestrain imposed strain the sample on

Conclusions