Materials, Structures, and Strategies for Foldable Electroluminescent Devices

Abstract Foldable electroluminescent (EL) devices have attracted much attention in recent years. By folding, 2D EL devices can be transformed to 3D structures, which play an important role in foldable, portable, and 3D displays. Foldability is similar to flexibility, but there are differences. Foldable electronic devices mainly focus on the properties of the folding regions, which are flexible or stretchable, while the non‐folding regions may be rigid. On the other hand, folding deformation is usually accompanied by severe and sharp compression and stretching in the folding regions, which have a significant impact on device performance. The unique deformation characteristics make foldable devices complicated in materials, structures, and strategies. In this review, the progress of foldable electronic devices is summarized. According to the crease characteristics, foldable devices are divided into a free‐folding type and a crease‐preset type. First, the materials, structures, and strategies of various non‐luminescent foldable electronic devices are summarized, which will enlighten the research of foldable EL devices. Then, the progress of foldable EL devices is summarized. Foldable EL devices are still in the early stage of research and still face many problems and challenges. It is hoped that this review can promote their rapid development.