Research On Metal Halide Perovskite Light-emitting Diodes

This paper focuses on the optimization of preparing process for the charge injection layer and light-emitting layer in perovskite light-emitting diode(PeLED).In addition,the hole injection layer-free and electron injection-free PeLED have been fabricated with the optimized preparing process,respectively.Furthermore,the effect of chloride ion concentration on the light-emitting peak of PeLED has been investigated.The details are discussed as follows.1.The preparing process of charge injection layer has been optimized.Firstly,the quality of TPBi electron injection layer of different thickness has been compared.The results show that the flatness of TPBi film of 45 nm is superior to the counterpart and the external quantum efficiency(EQE)of PeLED exhibits the highest.Then,the effect of PVK concentration on the performance of PeLED has been investigated.The results show that the morphology of perovskite film deposited on hole injection layer optimized with PVK of 2 mg/mL is superior to the counterpart,which leads to the highest EQE of 2.09%.2.The preparing process of perovskite light-emitting layer has been optimized.Firstly,the effect of four different solvent dosages of perovskite precursor solution on the performance of PeLED has been investigated.The results show that the morphology and thickness of perovskite film prepared with precursor solution containing 3 mL DMSO favor the injection and extraction of charge carriers,which lead to the superior EQE of 5.17%.Then,the effect of moment of dripping anti-solvent on the PeLED performance based on the optimized perovskite precursor solution has been investigated.The results show that the morphology of perovskite film is superior to the counterpart and the EQE of PeLED exhibits the highest when the anti-solvent is dripped at 30 s.3.The performance of hole injection layer-free and electron injection layer-free PeLED have been investigated,respectively.Perovskite precursor solution of different concentration(1 mL DMSO?3 mL DMSO)has been used to prepare hole injection layer-free PeLED and electron injection layer-free PeLED,respectively.The results show that the hole injection layer-free PeLED prepared with perovskite precursor solution containing 3 mL DMSO exhibits the highest EQE,while the electron injection layer-free PeLED prepared with perovskite precursor solution containing 1 mL DMSO exhibits the highest EQE.4.The effect of chloride ion concentration on the light-emitting peak of PeLED has been investigated.The thickness and roughness of quasi-two-dimensional perovskite light-emitting layer could be decreased by controlling the concentration of CsCl in precursor solution.Both of photoluminescence(PL)spectrum and electroluminescence(EL)spectrum would exhibit blue-shift with the CsCl concentration increasing.The PeLED exhibits the highest light-emitting peak at 494 nm and 504 run for PL and EL,respectively,which paves the way for blue PeLED.