Pander Piotr, Zaytsev Andrey V, Franca Larissa Gomes, Dias Fernando B, Kozhevnikov Valery N
Faculty of Chemistry, Silesian University of Technology, Strzody 9, 44-100 Gliwice, Poland.
Centre for Organic and Nanohybrid Electronics, Silesian University of Technology, Konarskiego 22B, 44-100 Gliwice, Poland.
Inorg Chem. 2023 Nov 13;62(45):18465-18473. doi: 10.1021/acs.inorgchem.3c02667. Epub 2023 Oct 31.
In this work, we introduce a spiro-fluorene unit into a phenylpyridine (CN)-type ligand as a simple way to deplanarize the structure and increase the solubility of the final platinum(II)···complex. Using a spiro-fluorene unit, orthogonal to the main coordination plane of the complex, reduces intermolecular interactions, leading to increased solubility but without significantly affecting the ability of the complex to form Pt···Pt dimers and excimers. This approach is highly important in the design of platinum(II) complexes, which often suffer from low solubility due to their mainly planar structure, and offers an alternative to the use of bulky alkyl groups. The nonplanar structure is also beneficial for vacuum-deposition techniques as it lowers the sublimation temperature. Importantly, there are no sp hybridized carbon atoms in the cyclometalating ligand that contain hydrogens, the undesired feature that is associated with the low stability of the materials in OLEDs. The complex displays high solubility in toluene, ∼10 mg mL, at room temperature, which allows producing solution-processed OLEDs in a wide range of doping concentrations, 5-100%, and EQE up to 5.9%, with a maximum luminance of 7400 cd m. Concurrently, we have also produced vacuum-deposited OLEDs, which display luminance up to 32 500 cd m and a maximum EQE of 11.8%.
在本工作中，我们将螺芴单元引入到苯基吡啶（CN）型配体中，作为一种使结构非平面化并提高最终铂（II）配合物溶解度的简便方法。使用与配合物主配位平面正交的螺芴单元可减少分子间相互作用，从而提高溶解度，但不会显著影响配合物形成Pt···Pt二聚体和激基缔合物的能力。这种方法在铂（II）配合物的设计中非常重要，因为铂（II）配合物通常因其主要的平面结构而溶解度较低，并且为使用庞大烷基提供了一种替代方案。非平面结构对真空沉积技术也有益，因为它降低了升华温度。重要的是，环金属化配体中不存在含有氢原子的sp杂化碳原子，这是与有机发光二极管中材料稳定性低相关的不良特征。该配合物在室温下在甲苯中的溶解度很高，约为10 mg/mL，这使得能够在5 - 100%的广泛掺杂浓度下制备溶液处理的有机发光二极管，外量子效率高达5.9%，最大亮度为7400 cd/m²。同时，我们还制备了真空沉积的有机发光二极管，其显示出高达32500 cd/m²的亮度和11.8%的最大外量子效率。
