Hierarchically engineered unibody Au mesh for stretchable and transparent conductors

Abstract

Stretchable and transparent conductors (STC) are a critical component of next-generation flexible optoelectronic devices. In this study, novel, junction-free, unibody Au conductors consisting of two-dimensional (2D) web-in-web structures are fabricated to obtain highly conductive STCs. First, a computer fluid dynamics (CFD) simulation is performed to evaluate the stretchability of the potential 2D mesh structures. Conventional photoresist (PR) lithography and electrospinning are then employed to realize the optimized web-in-web network, featuring a hierarchical mesh comprising symmetric large voids and asymmetric small voids. When the large voids in the mesh are aligned diagonally, the mesh can be stretched by up to 70% in stretchability tests without a significant increase in its sheet resistance. The results of the durability tests conducted herein indicate that the mesh structure remains rather stable after 1000 cycles under a constant tensile strain of 40%. In addition, it retains a high transparency of >90% in the visible light range. The use of scalable PR lithography and electrospinning facilitates easy scaling-up of the conductor to the dimensions of wearable devices. Thus, the proposed 2D web-in-web Au conductors and the associated fabrication routes are expected to replace conventional ITO electrodes in the next-generation stretchable optoelectronic devices.