Study On Perovskite Light Emitting Diodes Based On （PEA）₂FA₂Pb₃Br₁₀ Films

Compared with the traditional three-dimensional organic-inorganic hybrid perovskite,quasi-two-dimensional(quasi-2D)perovskite has better environmental stability,natural quantum well structure and greater exciton,attracting widespread concern in the field of luminescence.However,there are still some problems to be solved,such as uneven phase distribution and unbalanced carrier transport.At present,the research on the mechanism of carrier transport and recombination is also lagging behind.In this paper,we try to improve the phase distribution of quasi-two-dimensional perovskite films and optimize the transport layer of perovskite LED(Pe LED),and analyze the carrier transport characteristics of the device by transient electroluminescence experiment.The surface of(PEA)2FA2Pb3Br10 films was modified by solution post-treatment with NMABr.The results show that the three-dimensional phase on the surface of quasi-2D perovskite can react with the NMABr to form a quasi-two-dimensional phase,which passivates the surface defects,increases the exciton binding energy,photoluminescence quantum efficiency and excited state lifetime of the films.The current efficiency of the Pe LED based on modified quasi-2D perovskite film is increased from 18.8 cd/A to 21.3 cd/A.PVK film was used to modify PEDOT:PSS transport layer which block diffusion electrons from quasi-2D perovskite active layer very well.The experimental results show that the performance of the device with PEDOT: PSS/PVK transport layer is improved,the maximum current efficiency of the device increases from 19.5 cd/A to26.2 cd/A,and the lifetime of the device has been improved which shows that PVK can balance the injection of two kind of carriers and enhances the electroluminescent efficiency as well as stability of the device.Using the prepared devices,we carried out the transient electroluminescence experiment,and analyzed the characteristics of carrier transport and ion migration.The results show that the rise time of transient electroluminescence is about 5 ms,which is very disadvantageous for high-frame-rate display.