Hamze Rasha, Idris Muazzam, Muthiah Ravinson Daniel Sylvinson, Jung Moon Chul, Haiges Ralf, Djurovich Peter I, Thompson Mark E
Department of Chemistry, University of Southern California, Los Angeles, CA, United States.
Front Chem. 2020 May 8;8:401. doi: 10.3389/fchem.2020.00401. eCollection 2020.
The structural, photophysical and electrochemical properties of three luminescent 2-coordinate coinage metal (i.e., M = Cu, Ag, Au) complexes bearing a sterically bulky benzimidazolyl carbene, 1,3-bis(2,6-diisopropylphenyl)-1-H-benzo[d]imidazol-2-ylidene (), and carbazolide (Cz) as the anionic ligand were investigated. All the complexes emit in the deep blue region (~430 nm) with relatively narrow spectra (full width at half maximum = 44 nm, 2,300 cm) characterized by vibronic fine structure in nonpolar media (methylcyclohexane at room temperature), and with high photoluminescence quantum yields (Φ > 80%) and radiative rate constants ( ~ 7.8 × 10 s). The luminescence is solvatochromic, undergoing a red-shift in a polar solvent (CHCl) at room temperature that are accompanied by a decrease in quantum yields (Φ < 23%) and radiative rate constants ( < 4.0 × 10 s), whereas the non-radiative rate constants remain nearly constant ( ~ 1.0 × 10 s). The radiative rate is controlled via thermally assisted delayed fluorescence (TADF) and temperature-dependent luminescence studies of the gold complex ( ) in methylcyclohexane solution reveal an energy difference between the lowest singlet and triplet excited states of 920 cm. An organic light-emitting diode (OLED) fabricated using as a luminescent dopant has an external quantum efficiency of 12% and narrow, deep-blue emission (CIE = 0.16, 0.06).
研究了三种带有空间位阻较大的苯并咪唑基卡宾（1,3-双（2,6-二异丙基苯基）-1-H-苯并[d]咪唑-2-亚基）和咔唑化物（Cz）作为阴离子配体的二配位发光硬币金属（即M = Cu、Ag、Au）配合物的结构、光物理和电化学性质。所有配合物在深蓝色区域（430 nm）发射，光谱相对较窄（半高宽 = 44 nm，2300 cm），在非极性介质（室温下的甲基环己烷）中具有振动精细结构，并且具有高光致发光量子产率（Φ > 80%）和辐射速率常数（7.8×10 s）。发光是溶剂化变色的，在室温下在极性溶剂（CHCl）中发生红移，同时量子产率（Φ < 23%）和辐射速率常数（<4.0×10 s）降低，而非辐射速率常数几乎保持不变（~1.0×10 s）。通过热激活延迟荧光（TADF）控制辐射速率，对甲基环己烷溶液中的金配合物（）进行温度相关的发光研究，揭示了最低单重态和三重态激发态之间的能量差为920 cm。使用作为发光掺杂剂制备的有机发光二极管（OLED）具有12%的外量子效率和窄的深蓝色发射（CIE = 0.16, 0.06）。
