Facially Coordinated, Tris‐bidentate Purin‐8‐ylidene Ir(III) Complexes for Blue Electrophosphorescence and Hyperluminescence

Abstract Homoleptic fac‐substituted Ir(III) carbene complexes exhibit higher emission energy (in purple region) in comparison to their mer‐counterparts, prohibiting them to be employed in fabrication of blue emissive organic light‐emitting diode (OLED) devices. Now, the design of two distinctive CF₃‐functionalized purin‐8‐ylidene Ir(III) complexes, namely, m‐ and f‐CF₃ and m‐ and f‐PhCF₃, from new carbene motifs, 9‐(3‐(tert‐butyl)phenyl)‐7‐isopropyl‐2‐(trifluoromethyl)‐7,9‐dihydro‐8H‐purin‐8‐ylidene (A4) and 9‐(3‐(tert‐butyl)phenyl)‐7‐methyl‐6‐phenyl‐2‐(trifluoromethyl)‐7,9‐dihydro‐8H‐purin‐8‐ylidene (B7), having notably stabilized lowest unoccupied molecular orbital energy levels is reported. Hence, the corresponding f‐isomers f‐CF₃ and f‐PhCF₃ exhibit electroluminescence with peak max. at 478 and 495 nm, max. external quantum efficiencies (EQEs) of 10.4% and 12.8%, respectively. By using f‐CF₃ as assistant dopant to convey its energy to terminal emitter t‐DABNA and from f‐PhCF₃ donor to 2TCzBN acceptor, two hyper‐OLED devices are successfully fabricated, giving high max. EQE of 23.8%, full‐width at half‐maximum (FWHM) of 30 nm, and CIE_x,y coordinate of (0.13, 0.14) for the acceptor t‐DABNA, and max. EQE of 24.0%, FWHM of 28 nm, and CIE_x,y of (0.11, 0.36) for the acceptor 2TCzBN, confirming the advantages of these purin‐8‐ylidene Ir(III) complexes.