Properties Of Several Iridium Complexes With Bis(diphenylphorothioyl)amide Ligand

Over the past few decades,organic light-emitting devices(OLEDs)have gained immense popularity in both academic and industrial research.It is well-known that iridium(?)complexes are the most intensively investigated phosphorescent guest materials.Most of the phosphorescent iridium(?)complexes reported are cyclometaled complexes with two main ligands and one ancillary ligand.The alternation of ancillary ligand in iridium complexes can significantly change the photo-electrical properties.Therefore,development of novel ancillary ligands to achieve stable and efficient phosphorescent iridium(?)complexes for high-efficiency OLEDs remains to be a significant challenge.In this work,we designed a series of novel iridium(?)complexes featuring a new bis(diphenylphorothioyl)amide ancillary ligand.The properties of OLEDs based on these complexes are also studied.1.Four novel iridium(?)complexes were synthesized with pyridine derivatives ligands and bis(diphenylphorothioyl)amide ligand.The complexes exhibited pronounced blue shift in the emission profiles,compared with the complexes using tpip as the ancillary ligand with the same main ligands,due to the introduction of sulfur atom.Theoretical calculation suggested the ancillary ligand contribute to the distribution of the HOMO and LUMO levels,leading to the alternation of corresponding photo-physical properties.All the complexes showed high synthesis yields,syblimation yields as well as thermal stability.The OLEDs utlizing these complexes as dopants showed decent performances.Device using Ir(tfppy)2(Stpip)as emitter achieved the maximum current efficiency of 73.6 cd A-1.Furthermore,the efficiency roll-off was very mild.This work provides a new strategy for the structural design of efficient and stable phosphorescent Ir(?)complexes for OLEDs.2.We synthesized three novel iridium(?)complexes with pyrimidine derivatives as main ligands and bis(diphenylphorothioyl)amide as ancillary ligand.It was evident from theoretical calculation and experiments that the introduction of pyrimidine group changes the distribution of the HOMO/LUMO and their photo-physical properties.All devices incorporating these complexes as dopants show excellent performances,ascribed to the introduction of pyrimidine group,which can significantly enhance the device performances.Double-EML device with the configuration of ITO/MoO3(5 nm)/TAPC(40 nm)/Ir complex(8 wt%):MCP(10 nm)/Ir(8 wt%):PPO21(10 nm)/TmPyPB(40 nm)/LiF(1 nm)/Al(100 nm)exhibited higher maximum luminance and maximum current efficiency of 38287 cd m-2 and 61.0 cd A-1.Single-EML device with the configuration of ITO/MoO3(5 nm)/TAPC(40 nm)/mCP(10 nm)/Ir(8 wt%):PPO21(10 nm)/TmPyPB(40 nm)/LiF(1 nm)/Al(100 nm)had a milder efficiency roll off.2-D3 using Ir(tfpmd)2(Stpip)as the emitter showed the decent EL performances with a maximum luminance and current efficiency of 39784 cd m-2 and 87.5 cd A-1.Furthermore,OLEDs with Ir(ttpmd)2(Stpip)as dopant show a blue emission at the wavelength of 463 nm.3.Three novel red iridium(?)complexes with phenyl isoquinoline,pyridyl isoquinoline and phenyl quinazoline derivatives as main ligands and bis(diphenylphorothioyl)amide as ancillary ligand were synthesized and their photo-electrical properties were studied.OLEDs with Ir(tfqzl)2(Stpip)as dopant showed better performances with maximum luminance and current efficiency of 36080 cd m-2 and 23.2 cd A-1.