New <scp>Quinoxaline‐Based</scp> Blue Emitters: Molecular Structures, <scp>Aggregation‐Induced</scp> Enhanced Emission Characteristics and <scp>OLED</scp> Application
Xiaoyu Mao, Fuli Xie, Xiaohui Wang, Qingsong Wang, Zhipeng Qiu, M.R.J. Elsegood, Jie Bai, Xing Feng, Carl Redshaw, Yanping Huo, Jian‐Yong Hu, Qing Chen
Abstract
Main observation and conclusion Three new deep blue light emitters, bearing quinoxaline with different substituents (biphenyl/pyrene) at the 1‐ or 2‐position, were synthesized by a Pd‐catalysed coupling reaction in high yields, and were fully characterized by 1 H/ 13 C NMR spectroscopy, single crystal X‐ray diffraction, and high‐resolution mass spectrometry (HRMS). The designed molecules exhibit good thermal stability ( T g > 452 o C). Single crystal X‐ray diffraction indicated the compounds containing pyrene units exhibiting π‐π stacking, and thus this family of compounds exhibited intramolecular charge transfer (ICT) and non‐typical and aggregation‐induced enhanced emission (AIEE) characteristics, possessing blue emission both in solution and in the aggregation (solid) state. Furthermore, a selected deep blue emitter was utilized as the emitting layer for the fabrication of doped organic light‐emitting diode (OLED) devices, which afforded a deep blue electroluminescence (EL) peak at 428 nm with a narrow full width at half maximum (FWHM) of 57 nm, and the Commission Internationale de L'Eclairage (CIE) chromaticity coordinates of (0.15, 0.06).