Optoelectronic properties of quasi-two-dimensional perovskite light-emitting diodes via poly(9-vinylcarbazole) interlayer modification

Perovskite light-emitting diodes (PeLEDs) have attracted much attention due to their excellent performance. In this work, phenylethylamine bromide (PEABr) was employed to modify perovskite phases, while Poly(9-vinylcarbazole) (PVK) was added as a hole transport layer between perovskite and PEDOT:PSS to engineer the device structure, which is predicted to improve the optoelectronic performance of PeLEDs synergistically. The doping of PEABr in MAPbBr 3 can improve the radiative recombination of the emission layer through the formation of two-dimensional perovskite phases and modified film morphology. When the ratio of MAPbBr 3 :PEABr is 1:0.25, the maximum luminance of the optimal device increased from 80 to 9000 cd/m 2 and the maximum external quantum efficiency increased from 0.02% to 1.63% compared with the control device without PEABr doping. In addition, the hole injection ability of the device is further improved by adding PVK as the hole transport layer. The introduction of PVK can also facilitate the interface modification via surface defect passivation. When the PVK concentration is 10 mg/ml, the maximum current efficiency and external quantum efficiency of the optimal device are increased to 13.70 cd/A and 2.70%, respectively. These findings can provide a basis for the enhanced performance of PeLEDs.