中性环金属铱（III）配合物，具有取代的N-杂环碳（NHC）配体，可用于高性能黄色OLED应用,Inorganic Chemistry

当前位置： X-MOL 学术 › Inorg. Chem. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

中性环金属铱（III）配合物，具有取代的N-杂环碳（NHC）配体，可用于高性能黄色OLED应用
Inorganic Chemistry ( IF 4.3 ) Pub Date : 2019-10-18 , DOI: 10.1021/acs.inorgchem.9b01678
Bingqing Liu ₁ , Mohammed A. Jabed ₁ , Jiali Guo ₂ , Wan Xu _{1,

3} , Samuel L. Brown ₄ , Angel Ugrinov ₁ , Erik K. Hobbie ₄ , Svetlana Kilina ₁ , Anjun Qin ₂ , Wenfang Sun ₁

Affiliation

一系列带有取代的N-杂环卡宾（NHC）辅助配体（（^C∧N）₂ Ir（R-NHC）的中性环金属化铱（III）配合物的合成，晶体结构和光物理，其中^C∧N和NHC分别指环金属化配体苯并[ h ]喹啉和1-苯基苯并咪唑。NHC配体被苯环C4'上的吸电子或供电子基团取代（R = NO ₂（Ir1），CN（Ir2），H（Ir3），OCH ₃（Ir4），N（CH ₃）₂（Ir5）或苯并咪唑环的C5（R = NO ₂（Ir6），N（CH ₃）₂（Ir7））。通过单晶X射线衍射分析确认了Ir1的构型。的地面和激发态性质IR1 - IR7由两个光谱方法和时间依赖密度泛函理论（TDDFT）的计算进行了调查。所有的配合物在大约200nm处具有中等强度的无结构吸收带。发起从C 440nm的^∧ Ñ基于配体^1个π，π * / ¹ CT（电荷转移）/ ¹d，d跃迁和非常自旋的³ MLCT（金属到配体的电荷转移）/ ³ LLCT（配体到的电荷转移）跃迁超过500 nm。吸电子取代基造成的轻微蓝移^1个π，π * / ¹ CT / ¹ d，d带，而给电子取代基诱导的该频带的相比于未取代的复合物的红移Ir3的。除了弱发射硝基取代的络合物IR1和IR6化合物的寿命短得多（≤160ns），其他配合物在有机溶液中的发射率很高，其微秒寿命约为。在室温下540-550纳米，与发射状态被主要分配给³ π，π* / ³ MLCT状态。尽管取代基对发射能量的影响微不足道，但对发射量子产率和寿命的影响却很大。所有配合物在460-700 nm处也显示出宽的三重态激发态吸收，并具有相似的光谱特征，表明最低的三重态激发态具有相似的血统。高发射率的Ir2用作有机发光二极管（OLED）制造中的掺杂剂。器件显示黄色发射，具有最大电流效率（η_c）为71.29 cd A ^–1，最大亮度（L _max）为32747 cd m ^–2，最大外部量子效率（EQE）为20.6％。这些结果表明利用这种类型的中性Ir（III）配合物作为有效的黄色磷光发射体的潜力。

"点击查看英文标题和摘要"

Neutral Cyclometalated Iridium(III) Complexes Bearing Substituted N-Heterocyclic Carbene (NHC) Ligands for High-Performance Yellow OLED Application

The synthesis, crystal structure, and photophysics of a series of neutral cyclometalated iridium(III) complexes bearing substituted N-heterocyclic carbene (NHC) ancillary ligands ((C^∧N)₂Ir(R-NHC), where C^∧N and NHC refer to the cyclometalating ligand benzo[h]quinoline and 1-phenylbenzimidazole, respectively) are reported. The NHC ligands were substituted with electron-withdrawing or -donating groups on C4′ of the phenyl ring (R = NO₂ (Ir1), CN (Ir2), H (Ir3), OCH₃ (Ir4), N(CH₃)₂ (Ir5)) or C5 of the benzimidazole ring (R = NO₂ (Ir6), N(CH₃)₂ (Ir7)). The configuration of Ir1 was confirmed by a single-crystal X-ray diffraction analysis. The ground- and excited-state properties of Ir1–Ir7 were investigated by both spectroscopic methods and time-dependent density functional theory (TDDFT) calculations. All complexes possessed moderately strong structureless absorption bands at ca. 440 nm that originated from the C^∧N ligand based ¹π,π*/¹CT (charge transfer)/¹d,d transitions and very weak spin–forbidden ³MLCT (metal-to-ligand charge transfer)/³LLCT (ligand-to-ligand charge transfer) transitions beyond 500 nm. Electron-withdrawing substituents caused a slight blue shift of the ¹π,π*/¹CT/¹d,d band, while electron-donating substituents induced a red shift of this band in comparison to the unsubstituted complex Ir3. Except for the weakly emissive nitro-substituted complexes Ir1 and Ir6 that had much shorter lifetimes (≤160 ns), the other complexes are highly emissive in organic solutions with microsecond lifetimes at ca. 540–550 nm at room temperature, with the emitting states being predominantly assigned to ³π,π*/³MLCT states. Although the effect of the substituents on the emission energy was insignificant, the effects on the emission quantum yields and lifetimes were drastic. All complexes also exhibited broad triplet excited-state absorption at 460–700 nm with similar spectral features, indicating the similar parentage of the lowest triplet excited states. The highly emissive Ir2 was used as a dopant for organic light-emitting diode (OLED) fabrication. The device displayed a yellow emission with a maximum current efficiency (η_c) of 71.29 cd A^–1, a maximum luminance (L_max) of 32747 cd m^–2, and a maximum external quantum efficiency (EQE) of 20.6%. These results suggest the potential of utilizing this type of neutral Ir(III) complex as an efficient yellow phosphorescent emitter.

更新日期：2019-10-19

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南

全部期刊列表>>