Forward to efficient solution-processed NIR-PLEDs: A new neutral [Ir (C∧N)2(N∧N)]-bis-heteroleptic Ir(III)-complex versus the cationic [Ir (C∧N)2(N∧N)]+-bis-heteroleptic Ir(III)-complex

Despite the reported bis-heteroleptic [Ir((CN)-N-boolean AND)(2)((NO)-O-boolean AND)]/[Ir((CN)-N-boolean AND)(2)((OO)-O-boolean AND)] emitters as the mainstream Ir(III)-complexes towards efficient NIR-OLEDs/PLEDs, the issue that the two kinds of neutral Ir(III)-complexes are troubled by the facile (NOH)-O-boolean AND/(OOH)-O-boolean AND-ancillary dissociation upon acid/thermal-hydrolysis, is still challenging. In this paper, two bis-heteroleptic-[Ir(iqbt)(2)((NN)-N-boolean AND)]/[Ir(iqbt)(2)((NN)-N-boolean AND)](+) NIR-emitters with the (NHN)-N-boolean AND/(NN)-N-boolean AND-ancillary (such as the 2-pyridylazole Hfprpz or 2,2'-bipyridine bpy) with significantly improved stability, namely one neutral [Ir(iqbt)(2)(fprpz)] (2) and the cationic {[Ir(iqbt)(2)(bpy)](+)center dot(PF6)(-)} (1), were obtained, respectively. By doping and solution-processing, their NIR-PLEDs-1/2 especially the NIR-PLED-2 with desirable high-performance (both the eta(Max)(EQE) of 5.53 % and weak (ca. 5 %) efficiency-roll-off) of the NIR-PLED-2, engender neutral-[Ir((CN)-N-boolean AND)(2)((NN)-N-boolean AND)]-bis-heteroleptic Ir(III)-complexes a new platform to efficient solution-processed NIR-PLEDs.