Facially Coordinated, Tris‐bidentate Purin‐8‐ylidene Ir(III) Complexes for Blue Electrophosphorescence and Hyperluminescence. Issue 23 (28th September 2022)

• Record Type: Journal Article
• Authors: Qin, Yanyan; Yang, Xilin; Jin, Jibiao; Li, Deli; Zhou, Xiuwen; Zheng, Zhong; Sun, Yingjie; Wong, Wai‐Yeung; Chi, Yun; Su, Shi‐Jian
• Is Part Of: Advanced optical materials. Volume 10:Issue 23(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-28
• Subjects: carbene -- cyclometalate -- hyperphosphorescence -- iridium -- organic light‐emitting diodes; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202201633
• Languages: English
• ISSNs: 2195-1071

Abstract

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‐8 H ‐purin‐8‐ylidene (A4 ) and 9‐(3‐( tert ‐butyl)phenyl)‐7‐methyl‐6‐phenyl‐2‐(trifluoromethyl)‐7, 9‐dihydro‐8 H ‐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. Abstract : By using assistant dopant f ‐CF3 and f ‐PhCF3 to convey its energy to terminal emitter t ‐DABNA and 2TCzBN, the fabricated hyper‐organic light‐emitting diode devices gave external quantum efficiency (EQE) of 23.8%, full‐width at half‐maximum (FWHM) of 30 nm, and CIE x, y of (0.13, 0.14), and EQE of 24.0%, FWHM of 28 nm, and CIE x, y of (0.11, 0.36), respectively.