Rational Tuning of Bis-Tridentate Ir(III) Phosphors to Deep-Blue with High Efficiency and Sub-microsecond Lifetime
Rational Tuning of Bis-Tridentate Ir(III) Phosphors to Deep-Blue with High Efficiency and Sub-microsecond Lifetime
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DOI：
10.1021/acsami.1c00238
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发表时间：
2021-03-24
影响因子：
9.5
通讯作者：
Chi, Yun
中科院分区：
文献类型：
--
作者：
Tai, Wun-Shan;Gnanasekaran, Premkumar;Chi, Yun
以带有咪唑叉或咪唑并[4，5-B]吡啶-2-亚基的卡宾钳形前螯合物PC 1中心点H-3（PF 6）（2）或PC 2中心点H-3（PF 6）（2），以及第二环化的2，6-二芳氧基吡啶螯合物L1 H（2）和L2 H（2），合成了一类新的双三齿Ir（III）配合物（Dap-1-4），不同之处在于中心吡啶基片段处的NMe 2供体。使用含时密度泛函理论（TD-DFT）的方法合理化的紫外和蓝色区域之间的各自的发射调谐。接下来，通过分别在卡宾钳形螯合物的中心苯基和外围咪唑并[4，5-B]吡啶-2-亚基实体处同时添加两个甲基和一个CF 3取代基来合成高效蓝色发光体（Dap-5）。在DPEPO中具有15重量% Dap-5的有机发光二极管（OLED）器件在468 nm处显示出电致发光，并且具有CIE（0.14，0.15）和16.8%的最大外量子效率（最大EQE），具有低效率滚降（在1000 cd m（-2）下的EQE为14.4%）;后者归因于相对缩短的三重激发态辐射寿命。这些结果突出了双三齿Ir（III）磷光体在制造实用蓝光OLED中的充分性。
A new class of bis-tridentate Ir(III) complexes (Dap-1-4) was synthesized using carbene pincer pro-chelates PC1 center dot H-3(PF6)(2) or PC2 center dot H-3(PF6)(2) with either imidazolylidene or imidazo[4,5-b]pyridin-2-ylidene appendages, together with a second cyclometalating 2,6-diaryoxypyridine chelate, L1H(2) and L2H(2), differed by a NMe2 donor at the central pyridinyl fragment. The respective emission tuning between the ultraviolet and blue region was rationalized using time-dependent density functional theory (TD-DFT) approaches. Next, a highly efficient blue emitter (Dap-5) was synthesized by concomitant addition of two methyl groups and a single CF3 substituent at the central phenyl and peripheral imidazo[4,5-b]pyridin-2-ylidene entities of the carbene pincer chelate, respectively. The organic light-emitting diode (OLED) device with 15 wt % Dap-5 in DPEPO shows electroluminescence at 468 nm and with CIE (0.14, 0.15) and a max external quantum efficiency (max EQE) of 16.8% with low efficiency roll-off (EQE of 14.4% at 1000 cd m(-2)); the latter is attributed to the relatively shortened triplet excited-state radiative lifetime. These results highlight the adequateness of bis-tridentate Ir(III) phosphors in fabrication of practical blue-emitting OLEDs.