Preparation And Properties Of Organic-inorganic Hybrid Perovskite Light-emitting Diodes

Organic-inorganic hybrid perovskite materials are considered as excellent choices for next-generation display and lighting sources due to their excellent optical properties,good carrier transport properties,flexible bandgap tunability,and high color purity.Due to the unique quantum confinement effect,low-dimensional organic-inorganic hybrid perovskites have better photoluminescence properties than three-dimensional materials.Low-dimensional perovskite light-emitting diode?PeLED?devices are expected to achieve higher external quantum efficiency?EQE?.Based on a simple solution method,by adding different amounts of PEABr to the perovskite precursor solution,a series of low-dimensional perovskite films were prepared.And a PeLED device with an EQE of14.2%was prepared in addition amount of 0.4 PEABr.Meanwhile,in order to further improve the EQE of low-dimensional FAPbBr₃ LED devices,Cs doping and ionic liquid grain surface passivation strategies are also used.Devices based on this active layer has a maximum brightness of 26220 cd·m^–2 and a maximum EQE of 20.2%,which is the highest EQE of currently low-dimensional FAPbBr₃ LED device.Compared with common organic-inorganic hybrid perovskites,the thermal decomposition temperature of CsPbBr₃ perovskite is higher,which shows a unique potential in the preparation of long-life PeLED.However,CsPbBr₃-based perovskite has high defect density and poor film quality.In order to prepare CsPbBr₃ PeLED with high efficiency and high operation stability,passivation of CsPbBr₃ is necessary.In this paper,we prepared a Cs PbBr₃-based PeLED with a maximum EQE of 16.86%and a half-life of more than 128 hours at an initial brightness of 100 cd·m^-2.Which was obtained via a strong binding force between the soft Lewis base 4-trifluoromethylbenzoate and soft lead,and the limitation of sodium ions on the growth of perovskite grains.