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Accessing the Triplet State in Heavy‐Atom‐Free Perylene Diimides
Author(s) -
Yu Zhenyi,
Wu Yishi,
Peng Qian,
Sun Chunlin,
Chen Jianwei,
Yao Jiannian,
Fu Hongbing
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201600300
Subject(s) - intersystem crossing , perylene , intramolecular force , photochemistry , triplet state , chemistry , excited state , aryl , singlet state , singlet oxygen , electron transfer , singlet fission , atom (system on chip) , polar effect , oxygen , stereochemistry , atomic physics , molecule , organic chemistry , physics , computer science , alkyl , embedded system
Previous studies of perylenediimides (PDIs) mostly utilized the lowest singlet excited state S 1 . Generation of a triplet excited state (T 1 ) in PDIs is important for applications ranging from photodynamic therapy to photovoltaics; however, it remains a formidable task. Herein, we developed a heavy‐atom‐free strategy to prompt the T 1 ←S 1 intersystem crossing (ISC) by introducing electron‐donating aryl (Ar) groups at the head positions of an electron‐deficient perylenediimide (PDI) core. We found that the ISC efficiency increases from 8 to 54 % and then to 86 % by increasing the electron‐donating ability of head‐substituted aryl groups from phenyl ( p ‐PDI) to methoxyphenyl (MeO‐PDI) and then to methylthioxyphenyl (MeS‐PDI). By enhancing the intramolecular charge‐transfer (ICT) interaction from p ‐PDI to MeO‐PDI, and then to MeS‐PDI, singlet oxygen generation via energy‐transfer reactions from T 1 of PDIs to 3 O 2 was demonstrated with the highest yield of up to 80 %. These results provide guidelines for developing new triplet‐generating PDIs and related rylene diimides for optoelectronic applications.