Defect Passivation Efficacy of 2D Perovskite Interlayer for Perovskite Sky-Blue Emission Toward High Device Efficiency

The deviated crystallization kinetics of solution-processed perovskite layers caused by the bottom interface is a barrier to comprehensively suppressing the defect formation and further to efficaciously improve the film quality and device performance. Herein, it is reported that the incorporation of a PEA2PbBr4 interlayer can effectively modify the crystallization process of the quasi-2D mixed-halide perovskite layers, resulting in enhanced Lewis acid-base interaction and improved film homogeneity, which contributes to the strong defect passivation efficacy toward efficient sky-blue emission. As a result, the devices with the bottom-interface modification show a maximum external quantum efficiency of 14.2%, impressively an outstanding power efficiency of 17.0 lm W-1, and an external quantum efficiency of 12.3% at 1000 cd m(-2). This work provides an insight into crystallization kinetics for defect suppression of the perovskite layer and further highlights the defect passivation efficacy of 2D perovskite-based bottom-interface modification toward high-efficiency sky blue-emitting diodes.