Study On Multilayer White Organic Light Emitting Diodes With All-solutions And Its Properties

Compared with thermal deposition processing,the solution processing shows a simple process,low-cost investment,high material utilization,flexible and large-area preparation and many other features,and has a promising future in OLED industrial application.Unlike evaporated OLEDs,solution preparation is susceptible to factors such as processing materials,solvents,and processing environments,resulting in impeded device fabrication or poor performance.At the same time,electroluminescent devices represented by organic materials?FWHM>40 nm?have been vigorously developed,accompanied by the development of processed materials,which have high color purity?FWHM<20 nm?,low-cost perovskite materials have become the subject of research by researchers.this dissertation focuses on the preparation of electroluminescent devices by solution processing.It is based on the common problems in solution processing and the preparation of light emitting layers of perovskite materials.Red,green,and blue electroluminescent devices are prepared and emitted.Three primary colors emit light to achieve white light emission.?1?Through the modification of the ZnO cathode interface layer and the preparation of the PEDOT:PSS anode interface layer,we investigated the solubility of the upper-layer film processing solvent on the underlying film,and improved PEDOT:PSS.The polar solution spin coating of the aqueous solution;in the preparation of the light-emitting layer,the host-guest doping system is used and the energy level matching is ensured,and the small-molecule host material?TCTA,26DCzppy?can be adhered by making full use of the PVK polymer host material.The combined features ensure the filmability of the light-emitting layer film,and red light and blue light electroluminescent devices have been successfully prepared.?2?Preparation and study of perovskite green electroluminescent devices using perovskite materials of formamidinium lead bromide,by comparing the photophysical properties and device performance of the light emitting layer films prepared at different molar ratios under the upside-down and inverted device structures The optimum device structure and molar ratio were determined;on this basis,a higher-quality light-emitting layer film was prepared by controlling the concentration of the precursor solution,and at the same time,it was comparatively verified that the film had high thermal stability;the device was prepared The maximum current efficiency is 6.24 cd/A,the maximum power efficiency is 7.53 lm/W,and the maximum external quantum efficiency is 1.66%.Finally,a dense and uniform high-quality perovskite light-emitting layer film is obtained by solvent engineering and prepared.The corresponding device has a maximum current efficiency of13.39 cd/A,a maximum power efficiency of 19.11 lm/W,and a maximum external quantum efficiency of 3.51%.At this point,a highly efficient green electroluminescent device based on FAPbBr₃ light-emitting layer film was successfully prepared.