2025年1月21日，香港城市大学Yun Chi研究小组在《德国应用化学》杂志发表论文，报道合成了异电性卡宾环金属螯合物Ir(III)，其具有蓝色发色团，并研究了其异构化、发射调节和有机发光二极管（OLED）器件制造。

Ir(III)配合物尤其以其在生成蓝色OLED荧光方面的优异光物理性质而闻名。在本研究中，研究者利用两种不同的羰基前螯合物LAH2+和LBH2+（或LCH2+）制备了异电性Ir(III)配合物，其中LAH2+携带一个氰基取代的苯并咪唑以及N-甲酰基附件，而LBH2+（或LCH2+）携带对称的苯并咪唑实体。

值得注意的是，m, f-ct14和m, f-ct15在高温下与单个LA螯合物发生可逆平衡。相比之下，采用两种LA螯合物只得到mer取代的m-ct16。所有Ir(III)配合物在溶液中均表现出蓝色光致发光（ΦPL≥78%），辐射时间短（τrad≤1.05 μs）。采用m-ct16的Ph OLED器件在5000 cd·m^-2下的外量子效率（EQE）为22.8%。

此外，基于m-ct16和v-DABNA的超级OLED的EQE1000为32.1% (EQE记录在1000 cd·m^-2)， J90为15.0 mA·cm^-2(电流密度在最大EQE的90%)。其抑制效率滚降（EQE在1000 cd·m^-2和10000 cd·m^-2)展示了蓝色OLED器件制造的里程碑式突破。

附：英文原文

Title: Iridium(III) Blue Phosphors with Heteroleptic Carbene Cyclometalates: Isomerization, Emission Tuning, and OLED Fabrications

Author: Yixin Wu, Manli Huang, Lin Cheng, Junyao Zhang, Yi Pan, Shek-Man Yiu, Kai Chung Lau, Jie Yan, Chuluo Yang, Yun Chi

Issue&Volume: 2025-01-21

Abstract: Ir(III) complexes are particularly noted for their excellent photophysical properties in giving blue OLED phosphors. In this study, two distinctive carbene pro-chelates LAH2+ and LBH2+ (or LCH2+) were employed in preparation of heteroleptic Ir(III) complexes, to which LAH2+ bears a cyano substituted benzoimidazolium along with N-mesityl appendage, while LBH2+ (or LCH2+) carries the symmetrical benzoimidazolium entity. Notably, the reversible equilibration at high temperature was observed for m, f-ct14 and m, f-ct15 with a single LA chelate. In contrast, only the mer-substituted m-ct16 was obtained upon employing two LA chelates. All Ir(III) complexes exhibited blue photoluminescence (ΦPL ≥ 78%) with short radiative lifetimes (τrad ≤ 1.05 μs) in solution. The Ph OLED device with m-ct16 afforded an external quantum efficiency (EQE) of 22.8% at 5000 cd m2. Moreover, the hyper-OLED based on m-ct16 and v-DABNA exhibited EQE1000 of 32.1% (EQE recorded at 1000 cd·m2) and J90 of 15.0 mA cm2 (current density at 90% of max. EQE). Its suppressed efficiency roll-off (EQE of 32.1% and 27.7% at 1000 cd·m2 and 10000 cd·m2) demonstrated a milestone in fabrication of blue OLED devices.

DOI: 10.1002/anie.202421664

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202421664