Synthesis And Photoelectric Properties Of Iridium(â…¢) Complexes With Carbene And Triazole As Auxiliary Ligands

Over the last three decades, OLED has been considered widely because of its amazing benifits compared to the traditional displays and more applications. OLED luminescence uses three primary colors including red、green and blue. The red and green luminescent material has been developed and can meet the OLED requirements. However, the progress of blue materials was slow and has become the bottleneck of realizing the full color OLED displays now. Thus, many researchers focus to synthesize the pure blue light materials with high efficiency. In this paper, the process of blue light materials with high efficiency is discussed as following:Eight kinds of phosphorescent materials were synthesized with carbene and triazole as auxiliary ligands. Four complexes (ppz)2Ir(ttz)CL,(ppz)2Ir(fptz)Cl,(ppz)2Ir(ttzH) and (ppz)2Ir(fptzH) are based on1-phenylpyrazole as the main ligands. The other four complexes (ppy)2Ir(ttz)Cl,(ppy)2Ir(fptz)Cl,(ppy)2Ir(ttzH) and (ppy)2Ir(fptzH) are based on2-phenyl pyridine as the main ligands. The structure of materials was characterized with’HNMR, MS and single crystal.(ppz)2Ir(ttz)Cl,(ppz)2Ir(fptz)Cl,(ppy)2Ir(ttz)Cl and (ppy)2Ir(fptz)C1are monodenate complexes and (ppz)2Ir(ttzH),(ppz)2Ir(fptzH),(ppy)2Ir(ttzH) and (ppy)2Ir(fptzH) are carbene complexes.Thermal decomposition temperatures of (ppz)2Ir(ttz)Cl,(ppz)2Ir(fptz)Cl,(ppz)2Ir(ttzH) and (ppz)2Ir(fptzH) complexes is312℃、289℃、336℃and336℃respectively. The first order of reduction potential of these complexes is about-1.32eV,-1.25eV,-1.32eV and-1.30eV. Phosphorescence spectrum of (ppz)2Ir(ttz)Cl,(ppz)2Ir(fptz)Cl,(ppz)2Ir(ttzH) and (ppz)2Ir(fptzH) is similar with the largest emission peak around410nm. EL spectra shows two photoluminescence peaks for the iridium complexes with monodentate ligand including (ppz)2Ir(ttz)Cl at440nm and544nm and (ppz)2Ir(fptz)Cl at432nm and500nm. However, the iridium complexes with carben ligand have one photoluminescence peak, photoluminescence peak for (ppz)2Ir(ttzH) and (ppz)2Ir(fptzH) at436nm and440nm. It should be noticed that all complexes are blue light-emitting materials.Thermal stability, electrochemistry and electronic spectroscopy of (ppy)2Ir(ttz)Cl,(ppy)2Ir(fptz)Cl,(ppy)2Ir(ttzH) and (ppy)2Ir(fptzH) complexes were obtained. UV-vis absorption peak for all complexes is about265nm, the phosphorescent spectrum of iridium complexes with monodentate ligand is similar and the largest emission peak wavelength are all at498nm. The wavelength for emission peak of (ppy)2Ir(ttzH) and (ppy)2Ir(fptzH) are about506nm and510nm, respectively. The EL spectrum was measured in same condition. The emission peaks wavelength of the electroluminescent spectrum for (ppy)2Ir(ttz)Cl,(ppy)2Ir(fptz)Cl,(ppy)2Ir(ttzH) and (ppy)2Ir(fptzH) are about536,528,516and496nm, respectively. The maximum blue shift is40nm.