Highly flexible transparent electrodes based on mesh-patterned rigid indium tin oxide

Hiroyuki Kuwae,Kosuke Sakamoto,Atsuki Nobori,Shuichi Shoji,Naofumi Kobayashi,Jun Mizuno

doi:10.1038/s41598-018-20978-x

Hiroyuki Kuwae, Kosuke Sakamoto + Show 4 more

Open Access

https://doi.org/10.1038/s41598-018-20978-x

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Journal: Scientific Reports	Publication Date: Feb 12, 2018
Citations: 76	License type: open-access

Affiliation: Waseda University

Abstract

We developed highly bendable transparent indium tin oxide (ITO) electrodes with a mesh pattern for use in flexible electronic devices. The mesh patterns lowered tensile stress and hindered propagation of cracks. Simulations using the finite element method confirmed that the mesh patterns decreased tensile stress by over 10% because of the escaped strain to the flexible film when the electrodes were bent. The proposed patterned ITO electrodes were simply fabricated by photolithography and wet etching. The resistance increase ratio of a mesh-patterned ITO electrode after bending 1000 times was at least two orders of magnitude lower than that of a planar ITO electrode. In addition, crack propagation was stopped by the mesh pattern of the patterned ITO electrode. A mesh-patterned ITO electrode was used in a liquid-based organic light-emitting diode (OLED). The OLED displayed the same current density-voltage-luminance (J-V-L) curves before and after bending 100 times. These results indicate that the developed mesh-patterned ITO electrodes are attractive for use in flexible electronic devices.

Highlights

Flexible electronic devices like organic light-emitting diodes (OLEDs), touch panels, and organic solar cells have attracted attention because of their unique properties like light weight, conformability, high mechanical stability, and high formability[1]
To verify the concept of the flexible mesh-patterned Indium tin oxide (ITO) electrodes, the tensile stress and strain on them in the bent state were simulated based on the finite element method (COMSOL AB, COMSOL Multiphysics software ver. 5.0)
We proposed a highly bendable transparent ITO electrode structure based on simple mesh patterns

Summary

Introduction

Flexible electronic devices like organic light-emitting diodes (OLEDs), touch panels, and organic solar cells have attracted attention because of their unique properties like light weight, conformability, high mechanical stability, and high formability[1]. There has been extensive effort devoted to developing flexible transparent electrodes for use in flexible electronics; for example, silver nanowires[2,3], Al nanowire networks[4], an Au nanosquare mesh[5], poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) films[6], and carbon nanotubes[7,8]. Flexibility of these conventional electrodes was realized through material ductility or malleability. Liquid organic semiconductors (LOSs) are used as emitters because they possess high potential for use in flexible electronic devices[24,25]

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Conclusion