Hasegawa Y, Yamada Y, Sasaki M, Hosokai T, Nakanotani H, Adachi C
Institute of Pure and Applied Sciences, University of Tsukuba 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan.
National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan.
J Phys Chem Lett. 2018 Feb 15;9(4):863-867. doi: 10.1021/acs.jpclett.7b03232. Epub 2018 Feb 7.
We fabricated a well-ordered homogeneous monolayer of disk-shaped, carbazolyl dicyanobenzene (CDCB)-based thermally activated delayed fluorescence (TADF) molecule, i.e., 4CzIPN((4s,6s)-2,4,5,6-tetra(9Hcarbazol-9-yl)isophthalonitrile) at room temperature on flat Ag(111), Au(111), and Cu(111) surfaces. The second layer of the 4CzIPN was also found to be well ordered. The electronic states of the well-ordered monolayer and multilayer of 4CzIPN were found to be nearly unchanged from that of the isolated molecule calculated by the density functional theory (DFT), suggesting that the ordered layers retain the TADF properties. Indeed, we demonstrated the delayed fluorescence and the nearly perfect in-plane alignment of the transition dipole moment of a 4CzIPN thin film on glass substrate even in an ambient condition. These results indicate that the well-ordered films of the disc-shaped carbazole-based TADF molecules could potentially be utilized in organic light-emitting diode (OLED) devices with high light outcoupling efficiency.
我们在室温下于平整的Ag(111)、Au(111)和Cu(111)表面制备了基于盘状咔唑基二氰基苯（CDCB）的热激活延迟荧光（TADF）分子，即4CzIPN（(4s,6s)-2,4,5,6-四(9H-咔唑-9-基)间苯二甲腈）的有序均匀单层膜。还发现4CzIPN的第二层也是有序的。通过密度泛函理论（DFT）计算发现，4CzIPN有序单层膜和多层膜的电子态与孤立分子的电子态几乎没有变化，这表明有序层保留了TADF特性。事实上，我们证明了即使在环境条件下，玻璃基板上4CzIPN薄膜的延迟荧光以及跃迁偶极矩几乎完美的面内取向。这些结果表明，基于盘状咔唑的TADF分子的有序薄膜有可能用于具有高光出射效率的有机发光二极管（OLED）器件。
