Blue light-emitting diodes based on halide perovskites: Recent advances and strategies

Metal halide perovskites, as a new generation of semiconductor materials, have been widely applied in various optoelectronic devices, especially in the field of perovskite light-emitting diodes (PeLEDs). The external quantum efficiencies (EQEs) of green, red, and near-infrared PeLEDs have exceeded 20% for the last few years, which are comparable to those of the state-of-the-art organic light-emitting diodes (OLEDs) and quantum-dot light-emitting diodes (QLEDs). However, the performances of blue PeLEDs lag far behind those of their counterparts, presumably due to the low quantum yields of blue perovskite films, the instability of the emission spectra, and the difficulties in charge injection for the devices under operation conditions. In this review, the structures and physical properties of blue emissive perovskite materials and the preparation methods of the corresponding perovskite films are firstly addressed. Then, the recent advances and strategies to improve the efficiency of blue PeLEDs are outlined, and the main challenges faced with the blue PeLEDs are also discussed. Finally, an outlook on blue LEDs based on perovskite materials is proposed.

Automated summary

Metal halide perovskites have been widely used in optoelectronic devices, with green, red, and near-infrared PeLEDs achieving high external quantum efficiencies. However, blue PeLEDs face challenges such as low quantum yields, emission spectrum instability, and difficulties in charge injection. Research is ongoing to improve the efficiency of blue PeLEDs and address these challenges.