Research On Solution-processing WOLED And Its Performance Optimization

White Organic light-emitting diode?WOLED?has wide application prospect in the field of full color display and lighting for its advantages of self-luminescence,low-energy consumption,long life,high bending,high resolution,full color and low driving voltage.However,WOLED still has the problems of high cost,low performance,and short lifetime,which seriously hinder the commercialization of the technology.Therefore,it has become a research hotspot in the global academia and business community.The solution-processing method is considered to be an important method to reduce the cost of device fabrication due to its low cost and simple preparation process.At the same time,with the joint efforts of researchers from all walks of life,the preparation of WOLED by solution-processing method has made great progress in the overall performance.In recent years,the successful application of nanomaterials in Organic light-emitting diode?OLED?has attracted much attention,the localized surface plasmon resonance?LSPR?effects of metallic nanoparticles?such as gold nanoparticles and silver nanoparticles?can effectively improve the compound velocity of exciton,and has a significant effect on improving the performance of OLED.Therefore,it is a very promising research area to use metal nanoparticles to enhance the performance of solution processing OLED devices with a simple structure.This paper mainly studies the preparation of high-performance WOLED by solution-processing method,and to introduce silicon dioxide coated silver nano cubic?Ag@SiO2 NCs?into WOLED to further improve the performance of the device.First,we prepared WOLED by solution-processing method,and studied the influence of the host materials and the mixing ratio of them,the interface modification layer,the hole and the electron transport layer thickness on the device performance,and optimized the performance of WOLED by solution-processing method of WOELD.Through a large number of experimental studies and comparisons,the optimized device structure is defined as ITO/PEDOT:PSS?45 nm?/26DCzPPy:TCTA?20 wt.%?:Firpic?10 wt.%?:PO-01?0.5 wt.%??x nm?/TmPyPb?45 nm?/LiF?1 nm?/Al?100nm?,the optimized WOELD efficiency is 28cd/A,but its efficiency is still less than the WOLED prepared by evaporation.The better level of the solution processing WOLED is achieved.Then,we spin-coated the prepared Ag@SiO2 NCs onto the PEDOT:PSS layer and the light-emitting layer based on the previous optimization.Comparing the efficiency of WOLED at four different concentrations of 0,1%,3%,and 5%,it was found that the performance of the device after adding Ag@SiO2 NCs was significantly improved.Through the characterization and analysis of the working principle of the device,we have two main findings.On one hand,the LSPR effect of silver nanoscale effectively enhanced the radiation rate of excitons.On the other hand,SiO₂ material reduces the hole transport in the emitting layer and promotes the hole/electron balance.When the concentration of Ag@SiO2 NCs is 3%,WOLED achieves the best performance and the efficiency reaches 54cd/A.The efficiency of WOELD without Ag@SiO2 NCs increased by 77.3%.