Highly Flexible CsPbI3 Perovskite Nanocrystal Light-Emitting Diodes

Graphical Highly flexible red light-emitting diodes were fabricated by using smooth Ag film as a cathode, photopolymer (NOA63) as a flexible substrate and CsPbI 3 perovskite nanocrystals as an emission layer, exhibiting a high color purity and EQE of 8.2%. The device has excellent flexibility and high mechanical robustness. 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.