Syntheses and phosphorescences of iridium (III) pyrazine-pyrimidine complexes

Much attention has been paid to the phosphorescent materials in recent years for their potential application as highly efficient electroluminescent (EL) emitters in organic light emitting devices (OLEDs). Heavy metal complexes, particularly those containing Pt(II) and Ir(III), where strong spin orbit coupling leads to singlet-triplet state mixing, can result in high efficient electrophosphorescence in OLED. Among the many kinds of metal complexes, Iridium complexes are the most effective and show intense phosphorescence at room temperature. The iridium complexes used in electroluminescent (EL) devices are octahedral with a 3+ oxidation state and the observed luminescence is the emission from a triplet MLCT ( metal-to-ligand charge-transfer) state or a ligand-based 3 (??-?? * ) excited state. The organic ligands in the complexes are generally a heterocycle that coordinates to the metal center via formation of an Ir-N and Ir-C bond. Both the EL efficiency and the emission wavelength of the device are affected greatly by this organic ligand.OpticsPhysics, MultidisciplinaryPhysics, Condensed MatterEICPCI-S(ISTP)