Silver Nanowire Networks: Mechano-Electric Properties and Applications
Journal
Materials
Date
2019.08.08
Abstract
With increasing technological demand on portable electronic and photovoltaic devices, it became critical to ensure electro-mechanical reliability of all components in devices. However, traditional electrodes based on ITO (indium tin oxide) have limited flexibility and suffer from expensive process cost, undermining its application towards flexible devices. It is logical to seek new materials for flexible electrodes to overcome the shortcomings of conventional electrodes. Among the several reported solutions including metallic and carbon nanowires or meshes, silver nanowire (Ag NW) networks are regarded as promising candidates due to their excellent electrical, optical and mechanical properties. More specifically, as electro-mechanical robustness is the key property required for flexible conductive electrodes, we focused on the electro-mechanical property of Ag NW networks for the various optoelectronic devices . This review focuses on the fabrications and electro-mechanical properties of Ag NW networks for the applications towards various flexible devices by summarizing notable findings and cases in the recent researches.
First, we discuss Ag NW networks-based electrodes prepared through various coating processes and their chemical, electrical and optical properties. The deposition process of Ag NW networks on certain substrate have been covered from solution-based coating process (drop-casting, spray coating, spin coating etc.) to commercial processes (slot-die and R2R coating). The electrical characteristics of Ag NW networks are also discussed by focusing on the electrical characteristics governed by percolation and electrical contacts of the networks. Second, the electro-mechanical properties of Ag NW networks were reviewed by describing individual property (electrical and mechanical properties) of NW networks with dynamic motions under cyclic loading as well as their combined properties of Ag NW networks. While mechanical characteristics such as flexibility and stretchability of Ag NW networks are primarily governed by the mechanical robustness of individual NWs, the electro-mechanical property of NW networks is affected both by the electrical percolation and connections of the networks. The improved electro-mechanical properties of Ag NW are also discussed by presenting Ag NW network based flexible electrodes prepared through various approaches including post-treatment and hybridizations. Third, various Ag NW networks based on flexible devices are discussed. Specifically, electronic, opto-electronic and bio devices are discussed by introducing the basic strategies, applications and challenges of each device. In the end, we give final remarks on the challenges in the current studies and discuss the direction of research in the field as well as future issues before being integrated into commercial devices.