Saturated red iridium(iii) complexes containing a unique four-membered Ir-S-C-N backbone: mild synthesis and application in OLEDs

摘要

A series of new iridium(iii) cyclometalated complexes (4tfmpiq)(2)Ir(tiptha), (4tfmpiq)(2)Ir(phdiptha), (4tfmpiq)(2)Ir(fphdiptha) and (4tfmpiq)(2)Ir(ipdptha) (4tfmpiq = 4-(4-(trifluoromethyl)phenyl)isoquinoline, tiptha = 1,1,3-triisopropylthiourea, phdiptha = 1,1-diisopropyl-3-phenylthiourea, fphdiptha = 3-(4-fluorophenyl)-1,1-diisopropylthiourea, ipdptha = 3-isopropyl-1,1-diphenylthiourea) containing a unique four-membered ring Ir-S-C-N backbone were facilely synthesized under mild conditions. By introducing different substituents such as isopropyl, phenyl, 4-fluorophenyl, diisopropylamine and diphenylamine on the thiourea ancillary ligands, not only the S-C-N ligands can be extensively derived, but also the emission colors (lambda(peak) = 627-636 nm) and photoluminescence quantum efficiencies (phi(P) = 38.0-42.0%) can be regulated. Employing these complexes as emitters, the organic light emitting diodes (OLEDs) exhibited good performances with a maximum external quantum efficiency (EQE(max)) of 13.1% for saturated red emission with CIE coordinates of (0.68, 0.32). These results demonstrate the great potential of the S-C-N ancillary ligands for developing new Ir(iii) complexes towards OLED applications.

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