Modulated emission from dark triplet excitons in aza-acene compounds: fluorescence versus phosphorescence

	Modulated emission from dark triplet excitons in aza-acene compounds: fluorescence versus phosphorescence
	Chen, Jianwei 1,2; Chen, Yi 3,4; Wu, Yishi 1; Wang, Xuedong 1,2; Yu, Zhenyi 1,2; Xiao, Lu 1,2; Liu, Yanping 1,2; Tian, He 3,4; Yao, Jiannian 1; Fu, Hongbing 1,5
刊名	NEW JOURNAL OF CHEMISTRY
	2017
卷号	41 期号:4 页码:1864-1871
英文摘要	In the field of organic light-emitting diodes (OLEDs), research interests focus on making the optically dark triplet excitons shine in order to increase the electro-optic conversion efficiency of devices. In this work, two kinds of phenazine compounds, i.e. dibenzo[ a,c] phenazine (DBP) and tribenzo[ a,c,i] phenazine (TBP), were synthesized and used as model compounds to regulate the emission efficiency of the dark triplet excitons by chemical modification. Charge-transfer induced ultrafast intersystem crossing (CT-ISC) with a time constant of similar to 1 ps was observed for these two phenazine derivatives upon photoexcitation with a high triplet yield of 77.1% for DBP and 58.7% for TBP. The triplet excited states of DBP can produce ultra-long phosphorescence with lifetime as long as 318 ms at 77 K. The quantum yield for phosphorescence (FP) is determined to be 8.45%. In sharp contrast, the triplet-excited (TBP)-T-3* undergoes an efficient reverse intersystem crossing (RISC) process, resulting in bright delayed fluorescence emission with negligible phosphorescence. A controllable luminescence behavior from the triplet states between fluorescence and phosphorescence in phenazine derivatives is demonstrated. Theoretical calculations reveal that the structure-dependent triplet evolution is due to the charge-transfer induced energy level alignment within these compounds. Our results may have potential applications in the design of OLEDs and high triplet yield pure organic materials.
语种	英语
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/38121]
专题	化学研究所_光化学实验室
作者单位	1.Chinese Acad Sci, Inst Chem, BNLMS, Beijing 100190, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100039, Peoples R China 3.East China Univ Sci & Technol, Key Lab Adv Mat, Shanghai 200237, Peoples R China 4.East China Univ Sci & Technol, Inst Fine Chem, Shanghai 200237, Peoples R China 5.Capital Normal Univ, Dept Chem, Beijing 100048, Peoples R China
推荐引用方式 GB/T 7714	Chen, Jianwei,Chen, Yi,Wu, Yishi,et al. Modulated emission from dark triplet excitons in aza-acene compounds: fluorescence versus phosphorescence[J]. NEW JOURNAL OF CHEMISTRY,2017,41(4):1864-1871.
APA	Chen, Jianwei.,Chen, Yi.,Wu, Yishi.,Wang, Xuedong.,Yu, Zhenyi.,...&Fu, Hongbing.(2017).Modulated emission from dark triplet excitons in aza-acene compounds: fluorescence versus phosphorescence.NEW JOURNAL OF CHEMISTRY,41(4),1864-1871.
MLA	Chen, Jianwei,et al."Modulated emission from dark triplet excitons in aza-acene compounds: fluorescence versus phosphorescence".NEW JOURNAL OF CHEMISTRY 41.4(2017):1864-1871.