Structural modifications are a successful and commonly used approach to tune the emission properties of diverse fluorophores,but extending this approach to heavy-atom-free persistent luminophores has so far been unsuc...Structural modifications are a successful and commonly used approach to tune the emission properties of diverse fluorophores,but extending this approach to heavy-atom-free persistent luminophores has so far been unsuccessful.Here we employed a novel strategy to demonstrate triplet–triplet energy transfer from an organic room-temperature phosphor(RTP)with persistent luminescence to an organic molecule with thermally activated delayed fluorescence(TADF).We illustrated this approach by preparing heavy-atom-free composite crystals of an RTP with a long-lifetime emission and a red emissive organic fluorophore with TADF to yield materials with emission above 650 nm.The emission arose from the triplet excited state of an acceptor undergoing thermally activated reverse intersystem crossing(RISC)to the emissive S1 state.Such composite crystal is the first organic material with persistent TADF,achieved by triplet–triplet energy transfer.展开更多
基金This study was financially supported by the National Natural Science Foundation of China(nos.21525206 and 21971023)Q.-Z.Y.and by the EPSRC Early Career Fellowship(no.EP/L000075/1)to R.B.
文摘Structural modifications are a successful and commonly used approach to tune the emission properties of diverse fluorophores,but extending this approach to heavy-atom-free persistent luminophores has so far been unsuccessful.Here we employed a novel strategy to demonstrate triplet–triplet energy transfer from an organic room-temperature phosphor(RTP)with persistent luminescence to an organic molecule with thermally activated delayed fluorescence(TADF).We illustrated this approach by preparing heavy-atom-free composite crystals of an RTP with a long-lifetime emission and a red emissive organic fluorophore with TADF to yield materials with emission above 650 nm.The emission arose from the triplet excited state of an acceptor undergoing thermally activated reverse intersystem crossing(RISC)to the emissive S1 state.Such composite crystal is the first organic material with persistent TADF,achieved by triplet–triplet energy transfer.
