摘要
Understanding and management of triplet excitons transition in the same molecule remain a great challenge.Hence,for the first time,by host engineering,manageable transitions of triplet excitons in a naphthalimide derivative NDOH were achieved,and monitored through the intensity ratio(ITADF/IRTP)between thermally activated delayed fluorescence(TADF)and room-temperature phosphorescence(RTP).Energy differences between lowest triplet excited states of host and guest were changed from 0.03 to 0.17 eV,and ITADF/IRTP of NDOH decreased by 200 times,thus red shifting the afterglow color.It was proposed that shorter conjugation length led to larger band gaps of host materials,thus contributing to efficient Dexter and inefficient Förster energy transfer.Interestingly,no transition to singlet state and only strongest RTP with quantum yield of 13.9%could be observed,when PBNC with loosest stacking and largest band gap acted as host.This work provides novel insight for the management and prediction of triplet exciton transitions and the development of smart afterglow materials.
基金
This work was financially supported by the National Natural Science Foundation of China(No.22235006)
the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology)
the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF013).Thanks to the AIE Institute(www.aietech.org.cn)for providing some technical assistance.We are also grateful to National Supercomputing Center in Shenzhen for theoretical calculation support.
