High color-purity ( λ em=845 nm) near-infrared (NIR) polymer light-emitting diode (PLED) based on one [ir(C∧N)2(N∧O)]-bis-heteroleptic Ir(III)-complex

The development of efficient color-purity near-infrared iridium(III) complexes with emission beyond 800 nm is extremely challenging. Herein, we report a new [Ir(C"N)2(N"O)]-bis-heteroleptic Ir(III)-complex [Ir(tbpz)2(L)] using Htbpz (tribenzo[a,c,i]phenazine) as the highly conjugated HC"N main ligand and HL ((E)-2-(phenylimino) methyl)phenol) as the N"OH ancillary ligand. The photophysical result of [Ir(tbpz)2(L)] demonstrates that its color-purity narrowband (lambda em = 835 nm; Phi PL = 1.9 %) NIR-emission with a FWHM (full width at half maximum) of 45 nm is arisen from the 3 ILCT-dominant (ILCT = intraligand charge transfer) T1 state. The solution-processed NIR-PLEDs based on [Ir(tbpz)2(L)] could achieve the desirable color-purity NIR-emission peaking at 845 nm with the eta EQE Max values of 0.18-0.33 %.