Highly Flexible CsPbI3 Perovskite Nanocrystal Light‐Emitting Diodes

Abstract The superior optical and electrical properties of perovskite nanocrystals (NCs) make them attractive for light‐emitting diodes (LEDs). However, making stable flexible LEDs still remains a big challenge. Here, highly flexible CsPbI 3 perovskite LEDs were fabricated using a photopolymer as the substrate, and an ultra‐smooth Ag films instead of ITO as the bottom electrode. Moreover, the device electron injection was also improved with Ag electrode. The flexible LEDs exhibited excellent electroluminescence characteristics with a low turn‐on voltage of 2.0 V and an external quantum efficiency of 8.2%. In addition, the flexible LEDs maintained their good performance after 1000 times of repeated 180 degree stretch‐release bending.