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White Light Luminescence from a Homo‐conjugated Molecule with Thermally Activated Delayed Fluorescence
Author(s) -
Zhou Ying,
Li Yao,
Zhang Rong,
Zhao Dahui,
Yan Qifan
Publication year - 2021
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202100397
Subject(s) - fluorescence , photochemistry , excited state , luminescence , photoluminescence , molecule , moiety , conjugated system , acceptor , quenching (fluorescence) , materials science , chemistry , optoelectronics , stereochemistry , optics , organic chemistry , atomic physics , physics , condensed matter physics , polymer
Luminophores with tunable emission properties are appealing due to various applications. Among those properties, thermally activated delayed fluorescence (TADF) has been attracting enormous research interests. Herein, we synthesized a 9,9’‐spirobifluorene based homo‐conjugated molecule 1 , which connects a diphenylamino moiety as electron donor and a naphthalimide group as electron acceptor via 2,2’‐positions of spirofluorene. Compound 1 displays dual emission behaviour with both blue and orange fluorescence. The one orange fluorescence around 555 nmshows sensitivity to oxygen and a prolonged lifetime of 284 ns in degassed toluene. Such characteristics imply TADF nature for this emission from a charge‐transfer excited state. The other emission at 440 nm with blue colour displayed resistance to oxygen quenching and a normal fluorescence lifetime of 1.5 ns. Compared with control molecule, this emission band is assigned as conventional fluorescence from a localized excited state. In addition, dual emission property allows molecule 1 to be modulated to emit white photoluminescence in thin film with a CIE color coordinate of (0.25, 0.33).