Efficient solution-processed NIR-PLEDs doped with one [Ir(C^N)(C’^N’)(N’’^O)-tris-heteroleptic Ir(III)-complex NIR-phosphor

Abstract

Among reliable solution-processed NIR-OLEDs/PLEDs doped with NIR-emissive iridium(III)-complexes, high-performance fully-solution-processed NIR-PLEDs remain a great challenge. Herein, through the C–H activation of IrCl3⋅3H2O (Method A) or [Ir(COD)(Cl)]2 (Method B) with equimolar amount of the Hiqbt (HC^N) and Hdpqx (HC’^N‘) ligands, and the subsequent metalation with the N”^OH-ancillary ligand Hpbi, a new [Ir(C^N)(C’^N’)(N’’^O)]-tris-heteroleptic Ir(III)-complex [Ir(iqbt)(dpqx)(pbi)] (a relatively higher total yield of 41 % from Method B than that (19 %) from Method A) was obtained. Besides the NIR-emission (λPL = 710 nm) responsible from the highly conjugated Hiqbt ligand, its short T1-decayed lifetime of 0.48 μs while the large ΦPL of 0.37, are confirmed to correlate with the robust and low-symmetry geometry structure in the premise of T1-nature of 3LC/3MLCT-admixed transitions with the 3ILCT-dominant (Hiqbt; 74.49 %). Moreover, through the low-cost solution-processing or fully-solution-processing, the [Ir(iqbt)(dpqx)(pbi)] doped NIR-PLED-A or NIR-PLED-B was realized, respectively, whose high-performance (ηEQEMax = 6.61 % versus 5.31 %; λEL = 706/707 nm) should be resulted from the equivalent carries' injection/transport from TmPyPB-assisted LiF/Al cathode while Ba/Al cathode.