Materials, Device Structures, and Applications of Flexible Perovskite Light-Emitting Diodes

The flexible type of displays, which can alter their shape freely (e.g., bendable or foldable displays) according to situational demands, is under an intense spotlight due to applications in human-friendly mobile electronics. Among various types of light-emitting diodes (LEDs), meanwhile, perovskite-based LEDs (PeLEDs) have garnered particular attention in recent years as next-generation optoelectronic devices due to their exceptional optical characteristics, such as high efficiency (up to theoretical limits), high color purity, wide color gamut over the entire visible range, and ultrathin form factor. By integrating perovskite materials on an ultrathin flexible substrate with a proper encapsulation layer, the flexible PeLEDs, which can conform to various curved surfaces and be stably operated in an ambient condition, have been developed. Here, recent advances of the flexible PeLEDs are reviewed. First, light-emitting materials and device structures for the PeLEDs are introduced. Then, research progress on the flexible PeLEDs, either with and without the encapsulation layer are summarized. Next, some representative application examples of the flexible PeLEDs are briefly discussed. Finally, this review includes a brief discussion on future prospects.Y