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Disentangling Multiple Effects on Excited‐State Intramolecular Charge Transfer among Asymmetrical Tripartite PPI‐TPA/PCz Triads
Author(s) -
Yang Sirui,
Cao Chen,
Islam Amjad,
Sun Shanshan,
Deng Ziqi,
Li Jiayu,
Ni Shaofei,
Tong QingXiao,
Li MingDe
Publication year - 2021
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.202002862
Subject(s) - excited state , triad (sociology) , triphenylamine , intramolecular force , chemistry , photochemistry , electron transfer , fluorescence , atomic physics , stereochemistry , physics , psychology , psychoanalysis , quantum mechanics
By utilizing the bipolarity of 1,2‐diphenylphenanthroimidazole (PPI), two types of asymmetrical tripartite triads (PPI‐TPA and PPI‐PCz) were designed with triphenylamine (TPA) and 9‐phenylcarbazole (PCz). These triads are deep‐blue luminescent materials with a high fluorescence quantum yield of nearly 100 %. To trace the photophysical behaviors of these triads, their excited‐state evolution channels and interchromophoric interactions were investigated by ultrafast time‐resolved transient absorption and excited‐state theoretical calculations. The results suggest that the electronic nature, asymmetrical tripartite structure, and electron–hole distance of these triads, as well as solvent polarity, determine the lifetime of intramolecular charge transfer (ICT). Interestingly, PPI‐PCz triads show anti‐Kasha ICT, and the charge‐transfer direction among the triads is adjustable. For the PPI‐TPA triad, the electron is transferred from TPA to PPI, whereas for the PPI‐PCz triad the electron is pushed from PPI to PCz. Exploration of the excited‐state ICT in these triads may pave the way to design better luminescent materials in the future.