Promising Hybrid Graphene-Silver Nanowire Composite Electrode for Flexible Organic Light-Emitting Diodes

Huiying Li,Yunfei Liu,Anyang Su,Yu Duan,Jintao Wang

doi:10.1038/s41598-019-54424-3

Abstract

Thanks to its high transparency, high carrier mobility, and thermal conductivity, graphene is often used as transparent conductive electrode (TCE) in optoelectronic devices. However, the low carrier concentration and high resistance caused by vacancy defects, grain boundaries, and superposed folds in typical graphene films limit its application. In this study, we propose a method to increase both the conductivity and carrier concentration in single-layer graphene (SLG) by blending it with silver nanowires (AgNWs). AgNWs provide connections between grain boundaries of graphene to improve charge-carrier transport. The AgNWs in this study can reduce the resistance of SLG from 650 Ω/◻ to 27 Ω/◻ yet still maintain a transmittance of 86.7% (at 550 nm). Flexible organic light-emitting diode, with a maximum 15000 cd m−2 luminance was successfully fabricated using such graphene and AgNWs composite transparent electrodes.

Highlights

In our work, we blend graphene with AgNWs to take advantage of beneficial composite structures of one-dimensional and two-dimensional materials to improve the electrical properties of graphene
Prior to fabricate the composite electrode, we first studied the graphene film via Raman spectroscopy
We used AgNWs in conjunction with a graphene-based electrode to improve the common problem of poor connectivity and low carrier density of single-layer graphene (SLG)

Summary

Introduction

We blend graphene with AgNWs to take advantage of beneficial composite structures of one-dimensional and two-dimensional materials to improve the electrical properties of graphene. AgNWs with very high length-diameter ratios were used to ensure a good combination of optical and electrical properties. The primary purpose of the nanowires is to reduce the effect of grain boundaries and overlap defects between graphene sheets by providing additional conductive pathways. We studied the interaction mechanism between graphene and AgNWs and considered the percolation theory of binary systems. To ensure suitability for optoelectronic devices, several flexible, green, organic light-emitting devices were fabricated with this novel transparent and flexible composite electrode. These devices reached a luminance of over 15000 cd m−2

Methods

Results

Conclusion