Improved Hole Injection into Perovskite Light‐Emitting Diodes Using A Black Phosphorus Interlayer.

The light‐output and efficiency of perovskite based light‐emitting diodes (PeLEDs) is limited by hole injection and high leakage current, generated by a high hole injection barrier and poor perovskite morphology, respectively. Here, a feasible strategy is reported to overcome both constraints by introducing 2D black phosphorus (BP) as hole injection layer in the PeLED stack. A continuous film composed of high‐quality, ultrathin, and large BP sheets on top of poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate simultaneously improves the hole injection and morphology of the green‐emitting inorganic CsPbBr3 perovskite. Inclusion of the BP enhances the external quantum efficiency of CsPbBr3 based PeLEDs from 0.7% to 2.8%. A strategy for enhancing hole injection current in perovskite light‐emitting diodes (PeLEDs) is demonstrated. By introducing a smooth and continuous 2D black phosphorus film as hole injection layer in a CsPbBr3‐based PeLED, the hole injection barrier and the CsPbBr3 film morphology are reduced and improved, respectively. As result, external quantum efficiency and light output are considerably enhanced. [ABSTRACT FROM AUTHOR]