Metal‐Based Flexible Transparent Electrodes: Challenges and Recent Advances

Flexible transparent electrodes (FTEs) with high optical transmittance, low sheet resistance, and high flexibility are critical and indispensable components of emerging flexible optoelectronic devices. Indium tin oxide (ITO), the major transparent conductive material used for optoelectronics nowadays, is not suitable for flexible applications because of its brittleness. In the past decade, researchers have developed a wide variety of new transparent conductive materials to replace ITO, among which metal‐based FTEs (m‐FTEs) including ultrathin metal films, metal nanowire networks, and metal meshes appear to be particularly promising. In this review, the authors summarize the major challenges of each type of metal‐based transparent materials and highlight the corresponding research strategies and remarkable achievements in recent years. In the following, the possibility of scalable production of such m‐FTEs from the perspective of the material choice and fabrication technology is discussed. Finally, the remaining challenges and the perspective of m‐FTEs are discussed. Metal‐based flexible transparent electrodes are emerging as the most promising candidates to replace the rigid indium tin oxide for the flexible optoelectronics. In the past decade, lab study has made remarkable achievements in their fundamental performance; that is, electrical conductivity, optical transparency, and mechanical flexibility, promoting a shift toward large‐scale production.