Metal nanowire-based transparent electrode for flexible and stretchable optoelectronic devices

High-quality transparent electrodes are indispensable components of flexible optoelectronic devices as they guarantee sufficient light transparency and electrical conductivity. Compared to commercial indium tin oxide, metal nanowires are considered ideal candidates as flexible transparent electrodes (FTEs) owing to their superior optoelectronic properties, excellent mechanical flexibility, solution treatability, and higher compatibility with semiconductors. However, certain key challenges associated with material preparation and device fabrication remain for the practical application of metal nanowire-based electrodes. In this review, we discuss state-of-the-art solution-processed metal nanowire-based FTEs and their applications in flexible and stretchable optoelectronic devices. Specifically, the important properties of FTEs and a cost-benefit analysis of existing technologies are introduced, followed by a summary of the synthesis strategy, key properties, and fabrication technologies of the nanowires. Subsequently, we explore the applications of metal-nanowire-based FTEs in different optoelectronic devices including solar cells, photodetectors, and light-emitting diodes. Finally, the current status, future challenges, and emerging strategies in this field are presented.