Preparation Of Bis(2-substituted-8-quinolinolato) Zinc And Novel Structure Design On Organic Light-emitting Device

Organic light-emitting device(OLED) is a new kind of plane display technology based on organic electroluminescent material.Because of the excellent display characteristics of OLED,it has been expected to be one of the most ideal and potential display technologies in the near future.OLED can also be widely applied in the field of solid-state illumination as a light-source in car monitor and laptop.This dissertation focused on synthesizing zinc complexes by chemically modifying alkyl or aryl in the 2-positon of ligand and using complexes as organic electroluminescent materials in place of the widest used material——AlQ₃.Through designing hole-blocking,energy-transfer and non-doping OLEDs,we discussed electroluminescent mechanism in depth and in detail.OLEDs with advantages of tunable color,simplified fabrication and better property were successfully obtained in this dissertation.The details are given as follows.Chap 1:IntroductionDue to its outstanding advantages,OLED has become one of the focuses in scientific research and international market competition.OLED's research progress, electroluminescent mechanism and performance assessment are presented in this chapter in detail.Chap 2:Synthesis of Bis(2-substituted-8-quinolinolato)zinc and Their Applications in OLEDIn this chapter,five bis(2-substituted-8-quinolinolato)zinc were synthesized and confirmed by ¹H NMR,MS,UV-Vis,FL spectroscopy and electrochemistry measurement.These zinc complexes were successfully applied in OLED as organic electroluminescent materials.Because of the different substituent in 2-position of quinoline ring,the electroluminescence emission wavelength of OLEDs varied from 540 nm to 561 nm. Chap 3:Fabrication and Electroluminescent Property of a Hole-Blocking OLEDA white organic light-emitting device with structure of ITO/NPB(N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl-4,4'-ylenediamine)/BCP( 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline)/Zn[2-(p-biPh)-8-Q-O]₂/Al was fabricated and its electroluminescent mechanism was studied.The mixture light from double emitting materials of NPB(blue-light emission) and Zn[2-(p-biPh)-8-Q-O]₂ (yellow-light emission) was achieved by effectively adjusting the thickness of BCP that functioned as a hole blocking layer.When a 2.0nm-thick BCP was used, white-light emission was obtained.With a lower turn-on voltage at about 6 V,the white OLED showed a maximum brightness of 130 cd/m² and current efficiency of 0.224 cd/A at 20 V.Chap 4:Organic Light-emitting Device Using Cascade Process in Energy TransferIn order to increase the energy transfer from host to guest in OLED, Zn[2-(p-biPh)-8-Q-O]₂ was used to assist the energy transfer from NPB to the red fluorescent dye DCJTB.OLEDs with structure of ITO/NPB/NPB:DCJTB/Zn[2-(p-biPh)-8-Q-O]₂/BCP/Al were fabricated.As the concentration of DCJTB was only 0.5%,red-light emissive OLED was successfully fabricated using F(o|¨)rster transfer theory at twice.In addition,by varying the distance of Zn[2-(p-biPh)-8-Q-O]₂ and the doping system,the efficiency of energy transfer was changed.When the distance was below 10 nm,Zn[2-(p-biPh)-8-Q-O]₂ had an influence in energy transfer on doping system.And the longer the distance was,the weaker the efficiency was.Chap 5:Fabrication and Electroluminescent Property of a Non-Doping OLEDA highly efficient fluorescent dye DCJTB and Zn(2-Ph-8-Q-O)₂ were used to fabricate a kind of novel non-doping OLED with a structure of ITO/NPB/ DCJTB/Zn(Q-Ph)₂/AlQ₃/Al.By varying the thickness of ultra-thin layer DCJTB, yellow-light,red-light and orange-light emission from OLEDs were studied.Their luminescent color,electroluminescent mechanism and recombination zone were optimized in this study.When a 0.5nm-thick DCJTB was used,a stable red emission was obtained.