Nature‐Inspired Metallic Networks for Transparent Electrodes

Nature offers structural solutions to various optimization problems. For example, an optimal, low‐shedding water transport at various scales is achieved with quasi‐fractal structures, shown to be close to optimal. In a series of projects, metallic network analogs of some of these solutions to make high‐efficiency transparent conductors are studied. Specifically, transparent conductors are developed by directly metalizing leaf venations, spider webs, and other organic fibers. Also, the natural process of self‐cracking, similar to that occurring in the mud of dried‐out riverbeds, is employed to develop masks for metallic network fabrications. These comprehensive studies and developments contributed to, and in some cases initiate new directions in the field of network transparent conductors. These structures offer performance exceeding those of conventional oxide‐based films, while providing a possibility of reduced processing expense. This paper provides a concise, comparative review of this study and other groups' efforts in recent years. In the context of applications, the performance criteria are defined, and with those as a guideline, practicality of the most promising networks is discussed.