Synthesis Of Cationic Iridium Complexes Based On Oxadiazole Ligands And Application In The Light-emitting Electrochemical Cells

In order to meet the increasing demand of information,information display technology becomes more and more attractive.As the information display technology research and exploration developing,we have found that the solid-state light-emitting electrochemical cells(LECs)is the advanced display technology,its further study has caught people's attention.Recently,solid-state light-emitting electrochemical cells(LECs)based on ionic transition metal complexes(iTMCs)have attracted much research interest since they have the advantages of a simple device structure,a low operation voltage and compatibility with air-stable electrodes.These properties enable LECs to be cost-effective,versatile and power-efficient organic light-emitting sources.The first solid-state LEC device was based on a polymer blend containing a light-emitting polymer,an ion-conducting polymer and an inorganic salt.Since the report of LECs based on an ionic transition metal complexs(iTMCs)in 1996 by Rubner et al,iTMC-based LECs have received ever increasing attention because they have several advantages over conventional polymer-based LECs.In iTMC-based LECs no ion-conducting material or inorganic salt are needed because the metal complexes are intrinsically ionic.Based on cationic iridium complexes structure,the ancillary ligands play a crucial role in increasing the efficiency and lifetime of device.By tailoring the ancillary ligands,the photophysical and electrochemical properties of the cationic iridium complexes can be finely tuned.In this study oxadiazole-type ligands which have been synthesized will be used to coordination with iridium,finally we get three cationic iridium complexes.We fabricate and study their photoluminescence and electroluminescence properties in detail.The main contents of the article are as follow:1.Based on above consideration,our work designed and synthesized oxadiazole ligand,then react with N^N ligands and achieved three new kinds of ionic iridium2.complexes.They are [Ir(OXD)2(bpy)]+(PF6-)(complex 1),[Ir(OXD)2(phen)]+(PF6-)(complex 2),[Ir(OXD)2(ttpl)]+(PF6-)(complex 3),where OXD is 2,5-diphenyl-1,3,4-oxadiazole is cyclometalated ligand,bpy is 2,2-Bipyridine,phen is 1,10-Phenanthroline and ttpl representing 1,4,8,9-tetraquinoline phenanthroline amine.3.Three new complexes had been synthesized and characterized by photophysical,electrochemical and theoretical methods.4.To investigate the electroluminescent properties of these complexes,LECs based on complexes 1-3 were fabricated with a structure of ITO/PEDOT:PSS(45 nm)/cationic iridium complex:IL(4:1)(40 nm)/Al(100 nm).[PEDOT:PSS is(poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)];IL is the ionic liquid1-butyl-3-methylimidazolium hexafluorophosphate(BMIMPF6).