Accessing the Triplet State in Heavy‐Atom‐Free Perylene Diimides |
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| Authors: | Dr. Zhenyi Yu Yishi Wu Qian Peng Chunlin Sun Jianwei Chen Prof. Jiannian Yao Prof. Hongbing Fu |
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| Affiliation: | 1. Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of chemistry, Chinese Academy of Sciences, Beijing, P. R. China;2. Graduate University of Chinese Academy of Sciences, Beijing, P. R. China;3. Beijing Key Laboratory for Optical Materials and Photonic Devices Department of Chemistry Capital Normal University, Beijing, P.R. China;4. Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P. R. China |
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| Abstract: | Previous studies of perylenediimides (PDIs) mostly utilized the lowest singlet excited state S1. Generation of a triplet excited state (T1) 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 T1←S1 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 T1 of PDIs to 3O2 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. |
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| Keywords: | charge transfer intersystem crossing perylene diimide singlet oxygen generation triplet excited state |
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