Lin Ling, Li Mingke, Li Yulong, Lin Youran, Huang Yu, Yu Yue, Ying Lei, Ma Yuguang
Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy and Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
Phys Chem Chem Phys. 2025 Jul 2;27(26):13821-13825. doi: 10.1039/d5cp00955c.
The hybridized local and charge-transfer (HLCT) state of emitters concomitantly features high exciton utilization characteristics. However, it remains challenging to simultaneously regulate the excited states and intermolecular packing of blue emitters for non-doped organic light-emitting diodes (OLEDs) applications. Based on the previously developed star blue emitter TPA-1PN by us, herein, we designed and synthesized an isomeric star-shaped blue emitter, namely TPA-4PN, through adjusting the dihedral torsion angles between the triphenylamine and phenanthrene fragments. The torsion angle (37.72°) of TPA-4PN is smaller than that of TPA-1PN (61.69°), which endows TPA-4PN with stronger localized excited state characteristics and closer intermolecular packing, leading to higher luminous efficiency associated with a narrower emission spectrum. The corresponding external quantum efficiency of non-doped blue OLEDs based on TPA-4PN reached 7.76%, with CIE coordinates of (0.157, 0.071).
发光体的杂化局域和电荷转移（HLCT）态同时具有高激子利用特性。然而，对于非掺杂有机发光二极管（OLED）应用而言，同时调控蓝色发光体的激发态和分子间堆积仍然具有挑战性。基于我们之前开发的星形蓝色发光体TPA-1PN，在此，我们通过调整三苯胺和菲片段之间的二面角扭转角，设计并合成了一种异构体星形蓝色发光体，即TPA-4PN。TPA-4PN的扭转角（37.72°）小于TPA-1PN的扭转角（61.69°），这赋予TPA-4PN更强的局域激发态特性和更紧密的分子间堆积，从而导致更高的发光效率以及更窄的发射光谱。基于TPA-4PN的非掺杂蓝色OLED的相应外量子效率达到7.76%，CIE坐标为（0.157, 0.071）。
