Molecular engineering of an electron-transport triarylphosphine oxide-triazine conjugate toward high-performance phosphorescent organic light-emitting diodes with remarkable stability

• 作者: Jian-Hua Zou Junbiao Peng Lin-Ye Wang Ling Peng Ling-Ling Chen Xu-Hui Zhu
• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2020,（7）
• 页码范围: 904-910
• 页数: 7页
• 语种: 英文

摘要

Organic electron-transport materials are an essential component to boost performances and stability of organic light-emitting diodes.We present a robust organic electron-transport compound 3-(6-(3-(4,6-bis(4-biphenylyl)-1,3,5-triazin-2-yl)phenyl)pyridin-2-yl)phenyldiphenylphosphine oxide by facilely coupling the triphenylphosphine oxide moiety to the 2-phenyl-4,6-bis(4-biphenylyl)-1,3,5-triazine unit via a 2,6-pyridinylene linker.It is well soluble in weakly polar solvents and possesses a high Tg of123 ℃ with an exceptional Td≈470 ℃ at 1％ weight loss and deep HOMO/LUMO levels of ca.-6.45/-3.06 eV.The phosphorescent spectrum measured in solid state at 77 K reveals a notable triplet energy of 2.88 eV.n-Doping with 8-hydroxyquinolatolithium (Liq) produces the electron mobility value of 4.66×10-5-3.21×10-4cm2V-1 s-1@(2-5)×l05Vcm-1.Moreover,the contrasting solubility of the bromo reaction intermediate and the new compound in alcoholic solvents facilitates separation.The characterizations of bottom-and top-emission green phosphorescent OLEDs involving this single Liq-doped electron-transport layer reveal long stability.In particular,the latter provides outstanding performances with 77.4 cd A 1 (corresponding to an EQE of 18.7％) and 86.8 lm W-1@ca.1000 cd m 2,based on the green emitter bis(2-phenylpyridine)(2-(4-methyl-3-phenylphenyl)pyridine)iridium(Ⅲ).Moreover,driven by a constant current for ca.640 h,the initial luminance of 1000 cd m-2 appears almost no decay.