| Due to the superior properties of low cost,short fabrication processing and flexibility,optoelectronic devices such as solar cell,photodetector,and luminescent devices,which are based on perovskite materials,have been the hot research spot recently.Among those optoelectronic devices,perovskite light-emitting diodes（PeLEDs）havemanyadvantagessuchasexcellentcolorpurity,high photoluminescence quantum yield and can be solution-processed which is ideal for large-scale roll-to-roll production.These imerits make it great potential candicate for next-generation high quality display and lighting devices.However,defects of perovskite film and interface also with the unstability in air,impede further improvement of PeLEDs energy conversion efficiency and stability.For PeLEDs,the excellent interfacial properties and quality of morphology can lead to the reduce of the non-radiative loss,which are the key parameters to determine the luminescent efficiency and stability of perovskite light-emitting diodes.Thus,an ultrathin layer of polymer material poly-ethylenimine ethoxylated（PEIE）is introduced in the device structure in this work,and the influence of layer thickness upon the device performance is studied.Meanwhile,in pursuit of higher performance PeLEDs,benzophenone as a crystallizing agent is introduced in perovskite solution and the influence of BP concentration the device performance is investigated.The detailed content is as following:（1）The effect of PEIE ultrathin layer with different thickness on the optoelectrical properties of the PeLEDs was studied.The results show that the maximum brightness and current efficiency of the devices first increase and then decrease with the increase of thickness of the PEIE ultrathin layer and the maximum luminancese and current efficiency reach 914.9 cd/m2 and 0.28 cd/A,respectively.Due to the enhancement of film morphology,non-radiative loss is effectively suppressed.Meanwhile,PEIE ultrathin layer can increase the energy level difference between the perovskite luminescent layer and the electron transport layer,reduce the electron injection,balance the carrier injection and thus improve the photoelectric performance of the devices.（2）The effect of PEIE ultrathin layer with different thickness on PeLEDs stability was investigated.The stability of the device is enhanced with the increase of the thickness of the PEIE ultrathin layer.Through discussion and characterization,it is found that due to the excellent air stability of PEIE ultrathin layer,it can prevent the erosion of perovskite film by water and oxygen,thus enhance the device stability.（3）The effect of BP concentration upon the device performance was investigated.The results show that the performance of the devices first increase and then decrease with the increase of concentration of the BP and the maximum luminancese and current efficiency reach 1057.6 cd/m2,which is 6 times to that of the control device.It is found that benzophenone can favor the heterogeneous nucleation of the perovskite,lower the energy barrier of nucleation,thus raising the rate of crystallization,making contribution to the growth of micron-scale MAPbBr3 single crystals.In summary,high performance PeLEDs devices were fabricated by interface modification and introducing crystallizing agent,which provided a new method for the preparation of high performance PeLEDs. |
