Preparation Of Low-voltage High-performance Monochrome Phosphorescent Iridium Complex Organic Light-emitting Diodes And Research On Related Materials

Currently,the phosphorescent organic light emitting device has been plagued by the high driving voltage,while has been facing the challenge of achieving high efficiency at high brightness conditions.In this thesis,we put forward the corresponding solution ideas to solve the problem of solution-processing monochrome phosphorescent device,in order to promote the application of monochromatic phosphor materials in O LED.Given the problem of high driving voltage in monochrome phosphorescent organic light emitting device,we proposed a blend host "stepped" structure,which was applied in OLED and then built a unique device structure as follows: ITO/PEDO T: PSS(35 nm)/EML(55 nm)/TPBI(35 nm)/Ca: Ag,in which the gust materials are commercialized blue,green,orange,red material.After the optimizing of doping ratio of the guest materials,the driving voltage of green phosphorescent OLED is improved to 2.74 V.As to the challenge of achieving high efficiency at high brightness conditions for the monochrome phosphorescent device,We have adopted a series of iridium(III)complexes based on the 4,2,6-dichloro-pyrimidine synthesized by cooperative research group,and then built a conventional device structure: ITO/PEDOT: PSS(35 nm)/PVK : OXD-7: wt % gust(55 nm)/TPBI(35 nm)/Ca: Ag,in which,gust materials are iridium(III)complexes based on 4,6-dichloropyrimidine.After the optimization of the doping ratio of the object materials,we got a series of monochrome phosphorescent device.The yellow-green phosphorescent OLED device in which the Ir(dpp)2TP is used as guest material exihibits the best performance.The brightness is up to 125072 cd/m2 and the current efficiency up to 40.4 cd/A.As a result,we achieve high efficiency at high brightness conditions for the monochrome phosphorescent device.Finally,we combine the "stepped" structure with the iridium(III)complexes Ir(dpp)2TP,Ir(dpp)2pic base on 4,6-dichloropyrimidine.Consequently,we fabricated an orange phosphorescent device with driving voltage of 3.6 V,brightness of 110091 cd/m2,the maximum efficiency of 38.59 cd /A;a green phosphorescent device with driving voltage of 2.9 V,brightness of 127227 cd/m2,the maximum efficiency of 53.88 cd/A.To a certain extent,we fabricated the iridium(III)complexes monochrome phosphorescent organic light emitting device with low driving voltage,high brightness and high luminous efficiency.