Color-purity near-infrared (NIR; λem=780 nm) and all-solution-processed polymer light-emitting diodes (PLEDs) based on the C1-symmetric [Ir (C∧N)2(N∧O)]-bis-heteroleptic Ir(III)-complexes

Despite concrete efforts to Ir(III)-complex-based NIR-OLEDs/PLEDs, most of them previously reported are not of color -purity NIR-emission, due to the considerable visible -light remnants in the NIR-emissive protocols. Meanwhile, for the limited Ir(III)-complex-based color -purity NIR-OLEDs/PLEDs, it remains a great challenge to realize their high-performance, besides the tackling of non -all -solution -processed operation cost. In this paper, based on the molecular design of [Ir (dpbq)2 (Ln)] (1-2, n = 1-2), the highly conjugated HC<^>N-main ligand Hdpbq renders its Ir(III)-complexes' desirable color -purity NIR-phosphorescence (lambda PL = 780 nm), while electrochemical properties and excited -state dynamics are deeply dependent on the varied N<^>OH-ancillary ligands with different electronic effects. Especially for the [Ir (dpbq)2 (L2)] (2), its color -purity NIR-phosphorescent highefficiency (phi PL = 3.6 %) is arisen from augmented 3MLCT effect and large transition dipole moment (TDM). Importantly, upon its all -solution -processing device fabrication, the first -example of all -solution -processed and color -purity NIR-PLED (lambda EL = 780 nm; eta EQEMax = 1.4 %), the best of our knowledge, was realized.