Theoretical Study of Conversion and Decay Processes of Excited Triplet and Singlet States in a Thermally Activated Delayed Fluorescence Molecule

	Theoretical Study of Conversion and Decay Processes of Excited Triplet and Singlet States in a Thermally Activated Delayed Fluorescence Molecule
	Peng, Qian 1; Fan, Di 1; Duan, Ruihong 1; Yi, Yuanping 1; Niu, Yingli 1; Wang, Dong 2; Shuai, Zhigang 2
刊名	JOURNAL OF PHYSICAL CHEMISTRY C
	2017-06-29
卷号	121 期号:25 页码:13448-13456
英文摘要	Quantitative understanding of the photophysical processes is essential for developing novel thermally activated delayed fluorescence (TADF) materials. Taking as an example 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene, a typical TADF-active molecule, we calculated the interconversion and decay rates of the lowest excited singlet and triplet states at different temperatures as well as the prompt and delayed fluorescence efficiencies at 300 K at the first-principles level. Our results can reproduce well the experimentally available data. It is found that the reverse intersystem crossing rate (k(RISC)) is sharply increased by 3 orders of magnitude, while the other rates increase slightly or remain unchanged when the temperature rises from 77 to 300 K. Importantly, k(RISC) reaches up to 1.23 X 10(6) s(-1) and can compete with the radiative and nonradiative decay rates of S-1 (1.11 x 10(7) and 2.37 X 10(5) s(-1)) at 300 K, leading to an occurrence of delayed fluorescence. In addition, our calculations indicate that it is the freely rotational motions of the carbazolyl between two cyano groups that are responsible for the interconversion between S-1 and T-1. The large torsional barriers of other three adjacent carbazolyl groups block the nonradiative decay channels of S-1 -> S-0, leading to strong fluorescence. This work would provide useful insight into the molecular design of high-efficiency TADF emitters.
语种	英语
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/39010]
专题	化学研究所_有机固体实验室
作者单位	1.Chinese Acad Sci, Beijing Natl Lab Mol Sci, Inst Chem, CAS Key Lab Organ Solids, Beijing 100190, Peoples R China 2.Tsinghua Univ, Dept Chem, Key Lab Organ OptoElect & Mol Engn, Beijing 100084, Peoples R China
推荐引用方式 GB/T 7714	Peng, Qian,Fan, Di,Duan, Ruihong,et al. Theoretical Study of Conversion and Decay Processes of Excited Triplet and Singlet States in a Thermally Activated Delayed Fluorescence Molecule[J]. JOURNAL OF PHYSICAL CHEMISTRY C,2017,121(25):13448-13456.
APA	Peng, Qian.,Fan, Di.,Duan, Ruihong.,Yi, Yuanping.,Niu, Yingli.,...&Shuai, Zhigang.(2017).Theoretical Study of Conversion and Decay Processes of Excited Triplet and Singlet States in a Thermally Activated Delayed Fluorescence Molecule.JOURNAL OF PHYSICAL CHEMISTRY C,121(25),13448-13456.
MLA	Peng, Qian,et al."Theoretical Study of Conversion and Decay Processes of Excited Triplet and Singlet States in a Thermally Activated Delayed Fluorescence Molecule".JOURNAL OF PHYSICAL CHEMISTRY C 121.25(2017):13448-13456.