Effect of small molecule additives on efficient operation of all inorganic polycrystalline perovskite light-emitting diodes

Perovskite light-emitting diodes (PeLEDs) have received increasing attention because of their unique saturated emission color and solution fabrication capability. In this work, we report our effort towards obtaining high performance cesium lead tribromide (CsPbBr₃)-based PeLEDs through controlled growth of the inorganic polycrystalline perovskite emissive layer. The effect of a small molecule additive 2-((4-biphenylyl)-5-phenyl-1,3,4-oxadiazole) (PBD) on the formation of the uniform pinhole free one-step-processed CsPbBr₃-based emissive layer was analyzed. The results reveal that the use of the PBD additive in the precursor solution enables the suppression of the leakage current in the PeLEDs, which is realized through improved charge transport and controlled growth of the CsPbBr₃-emissive layer. A maximum luminance of 9396 cd m^-2 was realized for the PeLEDs, prepared using an optimal PBD additive concentration in the perovskite precursor solution, which is >4 times that of the control PeLEDs fabricated using a pure CsPbBr₃-precursor solution (2455 cd m^-2).