Phase Modulation Of Quasi-2D PEA₂MA₃Pb₄Br₁₃ Perovskite By Vacuum Poling Treatment And Impacts On Light Emitting Performance

In this paper,we explore a new preparation method to optimize the quasi-two-dimensional bromide perovskite thin films for light-emitting devices.Based on the optimized device model,we study the dynamic carrier transport and radiation recombination process in such devices.The specific work is as follows:1.Study on Phase Regulation and Optoelectrical Performance of Quasi-2D Perovskite Light Emitting Diodes.In this work,we realize the random distribution of perovskite components with different n values in the whole film by using vacuum poling treatment to accelerate the crystallization process.This make us effectively manipulate the perovskite phase distribution in the vertical scale.We call this random phase distribution as uniform phase distribution to distinguish it from the ordered non-uniform vertical phase distribution.We have studied the optoelectrical properties of both kinds of phase distribution and found that the uniform phase distribution plays a very important role in the optoelectrical properties of two-dimensional perovskite.After vacuum poling treatment,the light emitting devices based on ITO/PEDOT:PSS/Quasi-2D Perovskite/Bphen/Ag show enhanced luminescence performance.Furthermore,it was found that the uniform distribution improved the electron transport performance,decreased the defect densities,and increased the luminescence lifetime,so that higher recombination efficiency could be obtained.At the same time,the cyclic J-V test results show that the vacuum poling treatment is helpful to reduce the ion migration and improve the device performance.This work provides a constructive scheme for enhancing charge transport and radiation recombination by phase distribution regulation and further improving the LEDs performance.2.The study of transport and recombination process in phase regulated devices.By testing the impedance spectrum of different voltages,as well as C-f,C-V,we found that the electrons and holes achieve more balanced injections in uniform phase distribution,so as to improve the efficiency of the radiative recombination.and because of the effective charge and energy transfer,the luminescence centers is located inside the film,thus reducing the recombination loss caused by the interface defects.We use linear,circularly polarized light to explores carrier transport and recombination process.The influence of phase distribution and carrier transport properties were studied to realize the relationship between the orbital-orbital interaction and radiative recombination efficiency.