Enhanced efficiency and stability of blue perovskite light-emitting diodes through dual defect passivation

Three-dimensional (3D) mixed-halide blue perovskites have shown great potential for achieving efficient perovskite light-emitting diodes (LEDs) at high brightness. However, the device performance has been hindered by defects in perovskite films. Here, we explore the use of poly(ethylene glycol)diacrylate to passivate surface defects in CsPb(Br_0.65Cl_0.35)₃ perovskite films through additive doping and post-treatment strategies. Our results demonstrate that this dual strategy effectively reduces defects in the mixed-halide perovskite film, leading to enhanced efficiency and stability of blue 3D perovskite LEDs. The device exhibits a peak external quantum efficiency of 7.2% and a luminance of 8933 cd m⁻², which are over two-fold higher than those of the device without defect passivation. Furthermore, a four-fold increase of operational lifetime is achieved.