Blue perovskite light-emitting diodes: opportunities and challenges

The great progress of light-emitting diodes (LEDs) has been made based on perovskites, and the external quantum efficiency of near infrared, red and green devices have reached > 20%, exhibiting their great potential applications in lighting and displays. However, the performance of blue perovskite LEDs is very poor, thus limiting their applications in the field of full-color displays. The blue perovskite LEDs can be achieved through mixed halides or quantum confinement effect. In this paper, we review the research progress of blue perovskite LEDs based on these two strategies, discuss the challenges to achieve high-performance perovskite LEDs and present our perspectives.